Wagner 2	2232	2666	673	1993	74.76	555	2111	79.18

Wagner 3	1718	2052	1352	700	34.11	1115	937	45.66

Crane 1	6245	7458	832	6626	88.84	686	6772	90.80

Crane 2	4285	5117	894	4223	82.53	737	4380	85.60

TOTALS	26843	32057	9733	22324	69.64	8026	24031	74.96

Table 6.3 Ozone Season Maryland Healthy Air Act NOx Emissions
Reductions:

Unit	2002 Emissions (Ozone Season Day)	2002 Emissions (Ozone Season =
153 Days)	Uncontrolled 2009 Emissions (Ozone Season Day)	Uncontrolled
2009 Emissions (Ozone Season = 153 Days)	2009 HAA Caps (Ozone Season =
153 Days)	2009 HAA Emission Reductions (Ozone Season)	2009 HAA
Reductions (Tons per Ozone Season Day)	2012 HAA Caps (Ozone Season = 153
Days)	2009 Uncontrolled Emissions - 2012 HAA Cap (Ozone Season)	2009
Uncontrolled Emissions - 2012 HAA Cap (Tons Per Ozone Season day)

Brandon Shores 1	9.68	1481.04	11.56	1768.68	1363	405.68	2.65	1124	644.68
4.21

Brandon Shores 2	7.60	1162.80	9.08	1389.24	1449	-59.76	-0.39	1195	194.24
1.27

Wagner 2	6.88	1052.64	8.21	1256.13	278	978.13	6.39	229	1027.13	6.71

Wagner 3	3.28	501.84	3.91	598.23	583	15.23	0.10	481	117.23	0.77

Crane 1	11.86	1814.58	14.16	2166.48	345	1821.48	11.91	284	1882.48	12.30

Crane 2	10.56	1615.68	12.61	1929.33	385	1544.33	10.09	317	1612.33	10.54

TOTALS	49.86	7628.58	59.53	9108.09	4403	4705	30.75	3630	5478	36

Portable Fuel Containers Rule:  Phase I

This measure introduces performance standards for portable fuel
containers and spouts. The standards are intended to reduce emissions
from storage, transport and refueling activities. The rule also included
administrative and labeling requirements. Compliant containers must
have: only one opening for both pouring and filling, an automatic
shut-off to prevent overfill, an automatic sealing mechanism when not
dispensing fuel and specified fuel flow rates, permeation rates and
warranties.

Source Type Affected

Any person or entity selling, supplying or manufacturing portable fuel
containers, except containers with a capacity of less than or equal to
one quart, rapid refueling devices with capacities greater than or equal
to four gallons, safety cans and portable marine fuel tanks operating
with outboard motors, and products resulting in cumulative VOC emissions
below those of a representative container or spout.

Control Strategy

Maryland adopted Phase I of the Ozone Transport Commission (OTC) Model
Rule for Portable Fuel Containers in January 2002.  The rule applies to
all counties in the nonattainment area.  Reductions from this rule
increase annually beginning with implementation in the State of Maryland
on January 1, 2004.

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.26

VOC Emission Reductions for 2009 (TPD):	0.32

Emission Benefit Calculations

Projected reductions are based on an emission reduction factor of 75%
after full implementation after 10 years.  Implementation began in 2004.
 In 2008, the emission reduction factor is 41.3%.  In 2009, the emission
reduction factor is 48.8%.

References

E.H. Pechan, “Control Measure Development Support Analysis for the
Ozone Transport Commission Model Rules”, March 31, 2001.

Architectural and Industrial Maintenance Coatings Rule

This rule requires manufacturers to reformulate various types of
coatings to meet VOC content limits. Affected products include
architectural coatings, traffic markings, high-performance maintenance
coatings and other special-purpose coatings. It uses more stringent VOC
content limits than the existing Federal consumer products rule.

Source Type Affected

The measure affects all manufacturers of affected coatings.

Control Strategy

Maryland adopted this rule on March 29, 2004.  The rule will apply to
all counties in the nonattainment area.   Compliance with this rule was
required as of January 1, 2004.

The VOC content limits in this rule are based on a Suggested Control
Measure (SCM) adopted by the California Air Resources Board (CARB) and a
State and Territorial Air Pollution Program Administrators/Association
of Local Air Pollution Officials (STAPPA/ALAPCO) model rule or OTC
coatings. Manufacturers are expected to comply with this rule using
primarily EPA Test Method 24.

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.39

VOC Emission Reductions for 2009 (TPD):	0.39

Emission Benefit Calculations

Projected reductions are based on an emission reduction factor of 31%,
based on Pechan (2001).

References

E.H. Pechan, “Control Measure Development Support Analysis for the
Ozone Transport Commission Model Rules”, March 31, 2001.

Consumer Products Rule:  Phase I

Phase I of the Consumer Products Rule required reformulation of
approximately 80 types of consumer products to reduce their VOC content.
It uses more stringent VOC content limits than the existing Federal
consumer products rule. The rule also contains requirements for labeling
and reporting.

Source Type Affected

Manufacturers of various specialty chemicals named in the rule, such as
aerosol adhesives, floor wax strippers, dry cleaning fluids and general
purpose cleaners.

Control Strategy

Phase I of the Ozone Transport Commission (OTC) Model Rule for
Reformulated Consumer Products became effective in the State of Maryland
on August 18, 2003.

Manufacturers are expected to demonstrate compliance with the rule
primarily through a California Air Resources Board (CARB) test method.
If complying with the VOC contents becomes difficult, flexibility
options are provided.

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.14

VOC Emission Reductions for 2009 (TPD):	0.14

Emission Benefit Calculations

Projected reductions are based on an emission reduction factor of 14.2
percent, based on Pechan (2001).

References

E.H. Pechan, “Control Measure Development Support Analysis for the
Ozone Transport Commission Model Rules”, March 31, 2001.

Industrial Adhesives and Sealants Rule

This rule establishes VOC content limitations for industrial and
commercial application of solvent-based adhesives and sealants. Controls
will cover adhesives, sealants, adhesive primers, sealer primers,
adhesive application to substrates, and aerosol adhesives.  VOC content
limits are similar to those contained in the CARB Reasonably Available
Control Technology (RACT) or Best Available Control Technology (BACT)
document for adhesives and sealants (Dec. 1998).

Source Type Affected

Manufacturers and distributors of industrial adhesives and sealants.

Control Strategy

The State of Maryland will adopt the Ozone Transport Commission (OTC)
Model Rule for Industrial Adhesives and Sealants by May 1, 2008.

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.00

VOC Emission Reductions for 2009 (TPD):	0.10

Emission Benefit Calculations

Emission reductions are based on a 64 percent reduction in emissions of
VOC from the baseline. Further details are available in OTC Technical
Support Document (2006).

References

OTC 2006.  Identification and Evaluation of Candidate Control Measures:
Draft Technical Support Document.  Prepared by MACTEC Federal Programs,
Inc., Herndon, Virginia for the Ozone Transport Commission. August 4,
2006]

Portable Fuel Containers Rule:  Phase II

This measure expands existing performance standards for portable
gasoline containers and spouts to kerosene containers. The standards are
intended to reduce emissions from storage, transport and refueling
activities. The rule also included administrative and labeling
requirements. Compliant containers must have: only one opening for both
pouring and filling, an automatic shut-off to prevent overfill, an
automatic sealing mechanism when not dispensing fuel and specified fuel
flow rates, permeation rates and warranties.

Source Type Affected

Any person or entity selling, supplying or manufacturing portable fuel
containers, except containers with a capacity of less than or equal to
one quart, rapid refueling devices with capacities greater than or equal
to four gallons, safety cans and portable marine fuel tanks operating
with outboard motors, and products resulting in cumulative VOC emissions
below those of a representative container or spout.

Control Strategy

The State of Maryland will adopt the Ozone Transport Commission (OTC)
Model Rule for the second phase of the portable fuel container rule by
May 1, 2008.

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.00

VOC Emission Reductions for 2009 (TPD):	0.03

Emission Benefit Calculations

Projected reductions are based on an emission reduction factor of 58%
after full implementation after 10 years.  Implementation will begin in
2009.  In 2008, the emission reduction factor is 0.00%.  In 2009, the
emission reduction factor is 5.8%.  Further details are available in OTC
Technical Support Document (2006).

References

OTC 2006.  Identification and Evaluation of Candidate Control Measures:
Draft Technical Support Document.  Prepared by MACTEC Federal Programs,
Inc., Herndon, Virginia for the Ozone Transport Commission. August 4,
2006

Consumer Products Rule:  Phase II

Phase II of the Consumer Products Rule involves adopting the CARB
7/20/05 Amendments which sets new or revises existing limits on 13
consumer product categories.  It uses more stringent VOC content limits
than the existing federal consumer products rule. The rule also contains
requirements for labeling and reporting.

Source Type Affected

Manufacturers of various specialty chemicals named in the rule, such as
aerosol adhesives, floor wax strippers, dry cleaning fluids and general
purpose cleaners.

Control Strategy

The State of Maryland will adopt the Ozone Transport Commission (OTC)
Model Rule for the second phase of the consumer products rule by May 1,
2008.

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.00

VOC Emission Reductions for 2009 (TPD):	0.02

Emission Benefit Calculations

Emission reductions are based on an additional 2 percent reduction in
emissions of VOC from the baseline. Further details are available in OTC
Technical Support Document (2006).

References

OTC 2006.  Identification and Evaluation of Candidate Control Measures:
Draft Technical Support Document.  Prepared by MACTEC Federal Programs,
Inc., Herndon, Virginia for the Ozone Transport Commission. August 4,
2006

Rule Phase In

The following rules have a phase in period for the Baltimore
Nonattainment Area and give the region phased in emissions benefits:

Area Sources:

Additional phase in of reductions from Federal Locomotives Rule

Federal Rule related to On-Board Refueling/vapor recovery for LD Trucks
(2004)

Nonroad Sources:

Federal 2004 Nonroad Heavy Duty Diesel Rule (negligible benefits by
2009)

6.3  Voluntary and Innovative Measures

EPA’s voluntary measures policy, “Guidance on Incorporating
Voluntary Mobile Source Emission Reduction Programs in State
Implementation Plans”, establishes criteria under which emission
reductions from voluntary programs are creditable in a SIP.  This policy
permits states to develop and implement innovative programs that partner
with local jurisdictions, businesses and private citizens to implement
emission-reducing behaviors at the local level.

Inclusion of the following programs in the control measures portion of
this attainment plan is not intended to create an enforceable commitment
by MDE or the State to implement the programs or to achieve any specific
emission reductions projected as a result of implementation of the
programs, and neither MDE, nor the State makes any such commitment.  In
addition, MDE does not rely on any emission reductions projected as a
result of implementation of these programs to demonstrate attainment.
While the emission reductions from these programs could be substantial
and could lead to significant regional air quality benefits, actual air
quality benefits are uncertain.  Consequently, projected emission
reductions from these programs are not included in the emission
inventory, the attainment modeling, the reasonable further progress
calculation or any other area of the SIP where specific projected
emission reductions are identified.

Regional Forest Canopy Program:  Conservation, Restoration, and
Expansion

Expanded tree canopy cover is an innovative voluntary measure proposed
to improve the air quality in Cecil County, Maryland.  Trees reduce
ground-level ozone concentrations by:

reducing air temperatures and reducing energy used for cooling, and

directly removing ozone and NOx from the air.

Modeling has clearly shown that trees reduce ozone levels. In addition,
trees in an urban setting have far-reaching water quality (e.g.
decreasing storm water runoff), habit and societal benefits. To achieve
a reduction in ground-level ozone under a tree canopy program, it will
be necessary to preserve the current canopy and plant and maintain a
significant number of new trees.

The current regional tree canopy is composed of mixed native hardwoods
and urban plantings.  On average these species require 30 years to
mature so the short term benefits of a tree program are not substantial
yet still significant.  To achieve area wide canopy expansion will
require long-term commitment by the state and local agencies, volunteer
organizations, and private landowners.

Achieving maximum benefits from this type of program will require the
following types of commitments:

1) Initiate and/or enhance efforts to support, monitor, evaluate, and
report preservation of existing urban tree canopy and canopy expansion
efforts.

2) Implement urban forestry programs to affect air and surface
temperature, wind speed, and reduce VOC emissions. Programs include
sustained tree planting, reduced mowing and lawn maintenance and tree
planting initiatives for streets, parking lots, and government-owned
facilities.

3) Providing assistance and outreach to the landowners and businesses to
encourage tree conservation, planting and maintenance.

4) Initiate development of a comprehensive plan that will establish a
detailed regional baseline and outline strategies to preserve, enhance,
increase, and protect measure and track overall forest canopy change in
the region over the next 20 years.

5) Monitor these activities and report annually.

Current Programs

While Maryland has over 40 state programs that support, encourage, or
require the planting of trees, five of these tools are of special
importance for implementation at the local level:

Forest Conservation Act

Critical Areas Act

Mitigation Requirements

Comprehensive Plans Requirements

Urban and Community Forestry Programs

Special attention will be paid to how these programs can be coordinated
with new local ordinances and initiatives to enhance their use in tree
protection, canopy preservation, and expansion to achieve regional air
quality (SIP) goals.

Control Strategy

Coordination

This type of measure will require collaboration among the various state
and local agencies that support, encourage, and require tree planting.
Currently, numerous agencies bear responsibility for implementing and
tracking tree planting related activities, but there is no centralized
repository for this information.  The state can be encouraged to commit
to create a new program to coordinate tree-planting programs. This
program would be housed within the Department of Natural Resources
Maryland Forest Service and would be charged with management of a tree
planting database and promoting outreach efforts to landowners and
stakeholder groups. This database would be used to compile baseline data
(including maps and descriptive information about each nonattainment
county in the planning area), information about tree plantings (new and
replacement trees) and canopy change.

Canopy Preservation

The state coordinating office will work with local governments to fully
implement key programs. Particular attention will be given to those who
set conservation, tree planting and canopy goals and reforestation
standards for local authorities to track during the development process.
Local authorities will be encouraged to:

track efforts aimed at preserving existing canopy,

provide the Resource agency with data regarding preservation efforts
including new ordinances and development tools,

.

The effectiveness of canopy preservation efforts could then be
periodically evaluated.

Public Outreach

The region would need to commit to undertake a public outreach program
designed to promote tree planting. This need could build upon the
Chesapeake Bay Agreement Forestry Directive and local land use
guidelines. Past initiatives under Maryland programs have included
financial incentives to private landowners for planting trees.   MDE
could potentially approach Baltimore Metropolitan Council, state
government agencies, and local governments to work with volunteer tree
planting organizations, landowners, and stakeholder groups to support
tree planting and conduct educational outreach regarding documenting and
reporting voluntary planting and maintenance programs.

Canopy Goals

.

Strategic Tree Planting

Biogenic volatile organic compounds (BVOCs), an ozone precursor, are
emitted by some tree species as a natural process.  Expanding the canopy
primarily with trees whose BVOC emissions are lower will have a
significant impact on overall emissions, a key issue in reducing BVOCs.
A right tree –right place strategy will need to be encouraged to
garner the maximum benefits from this type of program.

Clean Air Teleworking Initiative

The state of Maryland, on occasion, experiences unhealthful levels of
the air pollutants ground level ozone and fine particles.  When air
quality elevates to unhealthful levels it poses significant health and
economic impacts to the citizens of the state of Maryland.  To address
air pollution concerns and requirements, the State of Maryland has
implemented over 100 pollution control programs affecting industries,
small businesses, mobile sources, and the general public since 1990,
when the modern-day Clean Air Act was passed. These programs have
prevented nearly 800 tons of ozone-forming pollutants from entering the
air each day.  In order to inform the public about daily air pollution
levels the Maryland Department of the Environment has been accurately
forecasting and reporting air quality information since 1993.

Traffic congestion is a major problem in Maryland’s metropolitan areas
where  individuals waste hundreds of hours every year stuck in traffic
due to congested roadways.  Numerous studies have demonstrated that
telework programs are advantageous in addressing major environmental,
transportation, productivity, quality of life, and employment issues.

Reduced commuter road miles decrease air polluting vehicle emissions,
gasoline consumption, traffic congestion, and highway maintenance costs
for the citizens of Maryland.  It has been proven that telework provides
economic and organizational benefits to employers, resulting in
increased employee productivity, enhanced employee morale, improved
recruitment and retention of employees, reduced office space and parking
needs, reduced stress, increased job satisfaction, decreased absenteeism
costs, an expanded labor pool, and increased flexibility to meet the
needs of citizens.  The state of Maryland, as a major employer, has
recognized its leadership role to develop substantive programs, such as
teleworking, to reduce commuter road miles traveled by state employees
and enhance productivity

Objective

The objectives of this campaign are to 1) increase the number of
employees who telework in the Baltimore/Washington metropolitan area and
2) increase the frequency of employees who telework by linking
teleworking and air quality; specifically, encouraging employees to
telework on days when air quality is at its worst.

The decision to encourage teleworking on bad air days will be guided by
the Air Quality Index (AQI), a nationwide, color-coded scale used by the
U.S. Environmental Protection Agency to communicate air quality to the
public.  “Code Orange” is considered unhealthy for sensitive groups
(children, the elderly, and those with heart or lung conditions) and
“Code Red” is considered unhealthy for everyone.  “Code Purple,”

 which occurs very infrequently in the region, is considered very
unhealthy for everyone.  Clean Air Partners, a nonprofit organization
that encourages voluntary action to improve air quality, provides a
three-day air quality forecast to local employers through its Air
Quality Action Day (AQAD) program.  A copy of Clean Air Partners’ Air
Quality Action Guide, which incorporated the AQI, is shown in Figure
6.1. Teleworking is encouraged at Code Orange and above.

        Figure 6.1 Air Quality Action Guide

Approach

Encouraging employees to telework on poor air quality days may result in
numerous employees and managers working at home for several consecutive
days.  This will require advanced preparation by employees, managers,
and coworkers (in the office) to ensure transparency and a consistent
level of productivity.  While this may initially seem challenging from a
management perspective, the added benefit is that employees and managers
will become adept at teleworking concurrently, thereby increasing the
organization’s business continuity capabilities in the event of an
actual emergency.

Implementation

The following steps are recommended to help businesses successfully
launch their “Clean Air Teleworking” initiative in 2007:

Get Input from Managers – businesses should get input from several
managers to identify potential barriers and solutions to the “Clean
Air Teleworking” initiative.  This could be accomplished by conducting
one-on-one interviews with 4-5 managers or a small discussion group. The
input from the managers could then be used to shape how the program is
developed and implemented, starting with a small pilot involving a
couple of managers supportive of teleworking and the “Clean Air
Teleworking” initiative.

Become an AQAD Participant – businesses should become an Air Quality
Action Days participant so it can receive the Clean Air Partners’
three-day air quality forecast, which can then be distributed by email
to employees when a poor air quality day (Code Orange, Code Red, or Code
Purple) is forecasted.

Conduct Pilot – Select managers and employees who will be
participating in the “Clean Air Teleworking” pilot and launch the
program over the summer of 2007.  Conduct an orientation/training
session for participants prior to implementation and follow-up with
brief phone interviews after a multi-day episode to determine if there
were any problems.  Prepare a summary report at the end of the pilot and
share with management and employees.

Implement Tracking System – Ask participants to track their
participation using a web-based system that tracks auto emission
reductions resulting from teleworking (NOx, VOC, CO, and CO2), such as
TeleTrips (  HYPERLINK "https://www.secure-teletrips.com/"
https://www.secure-teletrips.com/ ).  This information can be reported
at the individual, department/team, and organizational level and
provides continuous feedback on how the program and participants are
improving air quality.  Furthermore, businesses should consider
recognizing individuals or teams/departments with the highest level of
participation and emissions reductions.

Communicate – businesses should send out several email communications
to all their employees prior to the launch of the “Clean Air
Teleworking” pilot, during implementation, and at the conclusion of
the pilot to explain objectives and keep employees informed.
Furthermore, employees not participating in the pilot should also
receive the air quality forecast for Code Orange, Code Red, and Code
Purple days and be encouraged to take other voluntary measures at work
and at home (e.g., carpooling, eating in the cafeteria rather than going
out for lunch, refueling after dusk, and postponing mowing.)

Expand Program – Share the results of the pilot with all staff and
encourage other managers and employees to participate in the program in
future years.  Repeat orientation/training for new participants prior to
implementation, conduct phone or on-line survey with participants during
implementation, track participation/results for all participants, and
recognize or reward individuals teams/departments with the highest level
of participation and emissions reductions.

An initial pilot program will be initiated throughout the Maryland
Department of the Environment (MDE) that will encourage telecommuting
opportunities for qualified personnel when air quality is forecasted to
be in the Code Orange (Unhealthy for Sensitive Groups) range or above.
The MDE pilot program will launch in May 2007.

Expansion of Program

Additional strategies will be employed to encourage a wider
participation in the Clean Air Teleworking Initiative.  Some of these
strategies will include: Promoting participation amongst all Maryland
State agencies.  Working with the Baltimore Metropolitan Council and the
Metropolitan Washington Council of Governments to promote program
throughout local jurisdictions.  Clean Air Partners will serve as the
work group to implement the program. Develop strategic plan for local
governments and federal agencies.  Encourage participation within
private sector. Develop a merit-based recognition/award system for
participation. Promote program throughout the Ozone Transport
Commission.  A timeline of the implementation steps is shown in Table
6.3.

Table 6.4	Clean Air Teleworking Time Line

Task/Step	Apr-07	May-07	Jun-07	Jul-07	Aug-07	Sep-07	Oct-07	Nov-07	Dec-07

1.0	Telework Toolkit

1.1	Research materials	x

1.2	Compile toolkit	x

1.3	Integrate with Clean Air Partners web site	 	x

2.0	Clean Air Teleworking Pilot

2.1	Recruit organization(s)	 	x	x

2.2	Develop/implement communications plan	 	x	x

2.3	Conduct interviews/focus groups with managers	 	x	x

2.4	Identify participants (e.g., specific units/departments)	 	x	x

2.5	Conduct orientation 	 	 	x

2.6	Launch and conduct pilot	 	 	x	x	x	x

2.6	Conduct "spot" phone interviews/email surveys 	 	 	x	x	x	x

2.7	Implement tracking system	 	x	x	x	x	x

2.8	Track and report results	 	x	x	x	x	x	x	x

2.9	Expand program	 	 	 	 	 	 	 	x	x

The Clean Air Teleworking Initiative will develop the program in close
coordination with other entities who have some role in telework
implementation (Commuter Connections, Maryland Telework Partnership with
Employers, Telework!Va, and the newly created Office of Telework
Promotion and Broadband Assistance in VA.

Supporting Material

Clean Air Partners will compile and customize a telework tool kit that
would be posted on the organization’s web site.  The tool kit would
provide on-line resources to help employers start or expand a telework
program, including the use of “episodic” teleworking on poor air
quality days.

Air Quality Benefits of an Aggressive Telecommute Strategy

To simulate the effects of a very aggressive telecommute program, the
University of Maryland modeled the air quality change that would result
from a 40% reduction of vehicle miles traveled from the road in the
nonattainment areas of Baltimore, Philadelphia, and Washington, D.C. on
38 high ozone days in the summer of 2002.  Changes in emissions were
implemented as a flat 40% reduction in vehicle miles traveled in each
county of the three nonattainment areas.  The effects of implementing
such a program were modeled using version 4.4 of the CMAQ model.  The
model results showed that across the three nonattainment areas tested,
an aggressive telecommute program has the potential for considerable
benefit to air quality, with fairly uniform benefits across all three
areas.  The highest monitors in the Philadelphia and Washington, D.C.
nonattainment areas would see the largest benefits from this program,
suggesting that it is targeting the most troublesome monitors on the
worst ozone days.  Benefits in all three nonattainment areas averaged
over 2 ppbv ozone.  The full report is included in appendix G

High Electricity Demand Day (HEDD) Initiative

Emissions from Electric Generating Units (EGUs) are higher on high
electric demand days, resulting in poorer air quality. High electrical
demand day (HEDD) operation of EGUs generally have not been addressed
under existing air quality control requirements, and these units are
called into service on the very hot days of summer when air pollution
levels typically reach their peaks.

The Ozone Transport Commission (OTC) has been meeting with state
environmental and utility regulators, EPA staff, EGU owners and
operators and the independent regional systems operators to assess
emissions associated with HEDD during the ozone season and to address
excess NOx emissions on HEDDs. The OTC has found that NOx emissions are
much higher on a high electrical demand day than on a typical summer day
and there is the potential to reduce HEDD emissions by approximately 25
percent in the short term through the application of known control
technologies. HEDD units consists of gasoline and diesel combustion
turbines, coal and residual oil burning units.

On March 2, 2007, the OTC states and the District of Columbia agreed to
a Memorandum of Understanding (MOU) committing to reductions from the
HEDD source sector. The MOU includes specific targets for a group of six
states to achieve reductions in NOx emissions associated with HEDD units
on high electrical demand days during the ozone season. These states
agreed to achieve these reductions beginning with the 2009 ozone season
or as soon as feasible thereafter, but no later than 2012. The remaining
OTC states including Virginia and the District of Columbia agreed to
continue to review the HEDD program and seek reductions where possible
but they do not have a formal emissions reduction target in the MOU.
The OTC MOU is included in Appendix D.

Emission Reductions from Transportation Measures

Substantial funding commitments have come from State and local agencies
and private employers for promotion of strategies to reduce mobile
emissions. Examples of these measures include idling reduction,
ridesharing, telecommuting, and transit use as well as vehicle
replacement and retrofit measures, and bicycle and pedestrian programs.
These funding commitments produce reductions in emissions, some of which
are being reflected in transportation plans.

Although these programs are working to reduce emissions from mobile
sources and play an important role in the transportation sector’s
contribution to cleaner air, neither MDE, nor the State intends their
inclusion in this SIP to constitute enforceable commitments to implement
these programs or to achieve any emission reductions projected as a
result of implementing these programs, and neither MDE, nor the State
makes any such commitment.  These directionally correct programs will
continue to be used outside of the SIP for transportation planning
purposes as needed.

The following are descriptions of selected emission reduction strategies
in Cecil County.

Traffic Flow Improvements (CHART)

The Coordinated Highways Action Response Team program, operated by MDOT
and Maryland State Police, focuses its operations on non-recurring
congestion such as backups caused by accidents. The Statewide Operations
Center, and the three satellite Operations Centers in the region, survey
the state’s roadways to quickly identify incidents through the use of
ITS (Intelligent Transportation System) technology. CHART also includes
traffic patrols, which have been operating during peak periods on many
of the state’s highways since the early 1990s. CHART and MdTA have a
number of ITS devices in Cecil County.  These include CCTV cameras,
variable message signs and 24 response vehicle and emergency traffic
controls along I-95 in Cecil County. Currently MdTA and CHART are
working together to install a CHART workstation that will allow the
opportunity to view all CHART and MdTA cameras in the county. These
continued incident management and emergency information improvements to
motorists will help reduce vehicular delay. In addition to existing MdTA
and CHART devices there are other additional installations proposed that
will help improve or maintain traffic flow along the following Cecil
County roadways: US 40, US 301, MD 213, and I-95.

Truck Stop Electrification (TSE)

Truck Stop Electrification allows truckers to shut down their engine and
obtain electric power and “creature comforts” while resting. TSEs
reduce diesel emissions and reduce noise and wear and tear on the truck
engine. IdleAire truck stops provide electricity (110V AC), cab
heating/cooling, television and movies, telephone and Internet access.
IdleAire has over 100 locations nationally, three in Maryland. The
Maryland sites are located in Baltimore and Jessup, both in the
Baltimore region. An additional TSE has been put in place in Cecil
County at I-95 and MD 279.

Electronic Toll Collection

The Maryland Transportation Authority (MdTA) commenced operation of its
electronic toll collection system, MTAG, at the authority’s three
Baltimore harbor crossing facilities in 1999. The I-95 Tydings Memorial
Bridge and US 40 Thomas J. Hatem Memorial Bridge crossings of the
Susquehanna River are also now equipped with electronic toll facilities.
An Automatic Vehicle Identification (AVI) toll decal, a form of
electronic toll collection, also is offered at the Hatem Bridge. This $5
AVI decal allows unlimited trips across the bridge during a one-year
period. Decals can be used only on two-axle vehicles and cannot be used
by vehicles being towed or towing other vehicles. As of January 2004, 45
percent of vehicles using MdTA facilities used electronic toll tags.
MdTA is a member of the E-Z Pass InterAgency Group, a coalition of
Northeast Toll Authorities. MdTA established reciprocity with the E-Z
Pass system in 2001, enabling travelers in Maryland, as well as at most
toll facilities in New York, New Jersey, Delaware, Pennsylvania,
Massachusetts, Virginia, and West Virginia to pay tolls using one
electronic device.

Maryland Commuter Tax Credit

As of January 2000, a tax credit went into effect statewide that allows
employers to claim a 50% state tax credit for providing transit benefits
(subsidy) to an employee of up to $52.50 per month, which an employer
may provide to an employee without tax consequences under the Federal
tax law. It is expected that the state tax credit will be even more
attractive to employers as a benefit to offer employees than the Federal
law (a direct tax credit as opposed to an allowable business expense).
This feature of the Maryland law also has the potential to encourage
increased transit use by low and moderate-income employees. Under
provisions of both the 1999 and 2000 Maryland laws, private non-profit
organizations will also be able to participate in the program. Employers
will be able to claim tax credits for providing transit passes and
vouchers, guaranteed ride home, and parking cash-out programs. Similar
to the IRS benefits, the Maryland Commuter Tax Benefit program does not
provide financial assistance to carpoolers. Information is also provided
online and employers are able to register to participate in the program
over the internet.

Bicycle/pedestrian Enhancements

Through MDOT, the Maryland State Highway Administration (SHA) has worked
to engineer and implement new and improved bicycle and pedestrian
facilities, and has implemented programs to encourage pedestrians. SHA
has a stated goal of providing 200 miles of marked bicycle lanes
throughout Maryland by December 31, 2006. In addition, SHA has developed
the Maryland SHA Bicycle and Pedestrian Guidelines to provide general
guidance on design. The state has a policy of considering sidewalks to
reinforce pedestrian safety and promote pedestrian access adjacent
to roadway projects being constructed or reconstructed. Special
efforts are made to facilitate pedestrian travel near schools. In
addition, bicycle safety and travel are being accommodated by
construction of wider shoulders and/or curb lanes to separate motor
vehicles from the cyclists. In regard to bicycle or pedestrian
travel in controlled access roadway corridors there is almost
always a separation between the bike or pedestrian travel and the
motor vehicles. Only along roadways where speeds or mix of the travel
modes could result in serious accidents are sidewalks and
bicycle travel not promoted.

Refurbishing MARC and other rail vehicles

In order to insure the reliability, safety and comfort of MARC equipment
the rolling stock is periodically overhauled. These include 26 MARC cars
that have been or are scheduled to be refurbished between FY2005 and FY
2008.  In addition, 23 locomotives are in the process of being
overhauled and retrofitted to cleaner Federally required TIER standards
in force at the time of the improvement. This is an ongoing effort that
started in FY 2005. All the locomotives will not be improved until 2012.
100 Metro rail cars have recently been overhauled to extend their life
and make them more comfortable and reliable for passengers and
commuters. The MARC Penn Line includes service to the Perryville station
in western Cecil County.

Park and Ride Lots

The SHA and MdTA have three park and ride lots in Cecil County adjacent
to I-95.  These lots serve to accommodate carpool based work
trips into the Baltimore and Wilmington regions.  The benefits of the
reduction in VMT and VT provides for a reduction in regional congestion
and vehicular emissions.

7.0  Reasonably Available Control Measure (RACM) Analysis

Section 172(c)(1) of the Clean Air Act requires State Implementation
Plans (SIPs) to include an analysis of Reasonably Available Control
Measures (RACM). This analysis is designed to ensure that the Cecil
County is implementing all reasonably available control measures in
order to demonstrate attainment with the 8-hour ozone standard on the
earliest date possible. This chapter presents a summary of analysis
conducted to determine whether the SIP includes all reasonably available
control measures. Full details of the analysis are included in Appendix
E.

The Maryland Department of the Environment (MDE) has prepared this RACM
analysis using two independently developed lists of potential control
measures.  The first list consists of the RACM analysis performed for
the Washington DC Region’s 8-hour Ozone SIP.  The MDE worked very
closely with all the DC region’s jurisdictions in the development of
the DC Region’s RACM analysis.  Understanding that the adjacent
Washington, DC non-attainment region is both extremely similar to the
metropolitan Philadelphia region and was also undertaking their RACM
analysis, MDE incorporated the Washington RACM criteria and analysis
into the 8-hour ozone SIP for Cecil County.

The Washington RACM analysis included a series of regional calls over
several months to review over 200 suggested measures from numerous
sources to create a master listing of measures.  Each of over 200
measures was individually evaluated against established RACM criteria
(the criteria is explained below).

In addition to a careful review of the Washington DC Region’s RACM
analysis the MDE also worked closely with the Baltimore Metropolitan
Council (BMC) in developing a small list of potential transportation
emission reduction measures during the fall of 2006.  This analysis
yielded a list of 24 specific measures that could be implemented in the
Baltimore Nonattainment area for emission reduction purposes.  Based on
the criteria used for RACM none of these 24 measures are to be
considered RACM but these measures shall be kept on a short list of
measures if the region needs additional reductions.

At the completion of the RACM analysis it was determined that no
measures met the criteria.

7.1 Analysis Overview and Criteria

The RACM requirement is rooted in Section 172(c)(1) of the Clean Air
Act, which directs states to “provide for implementation of all
reasonably available control measures as expeditiously as
practicable”. In its 1992 General Preamble for implementation of the
1990 Clean Air Act Amendments (57 FR 13498), EPA explains that it
interprets Section 172(c)(1) as a requirement that states incorporate in
a SIP all reasonably available control measures that would advance a
region’s attainment date. However, regions are obligated to adopt only
those measures that are reasonably available for implementation in light
of local circumstances. In the Preamble, EPA laid out guidelines to help
states determine which measures should be considered reasonably
available:

If it can be shown that one or more measures are unreasonable because
emissions from the sources affected are insignificant (i.e. de minimis),
those measures may be excluded from further consideration…the
resulting available control measures should then be evaluated for
reasonableness, considering their technological feasibility and the cost
of control in the area to which the SIP applies…In the case of public
sector sources and control measures, this evaluation should consider the
impact of the reasonableness of the measures on the municipal or other
government entity that must bear the responsibility for their
implementation.

In its opinion on Sierra Club v. EPA, decided July 2, 2002, the U.S.
Court of Appeals for the DC Circuit upheld EPA’s definition of RACM,
including the consideration of economic and technological feasibility,
ability to cause substantial widespread and long-term adverse impacts,
collective ability of the measures to advance a region’s attainment
date, and whether an intensive or costly effort will be required to
implement the measures. Consistent with EPA guidance and the U.S.
District Court’s opinion, the Cecil County/Wilmapco region has
developed specific criteria for evaluation of potential RACM measures.
Individual measures must meet the following criteria:

Will reduce emissions by the beginning of the 2008 ozone season (May 1,
2008)

Enforceable

Technically feasible

Economically feasible (proposed as a cost of $3,500-$5,000 per ton or
less)

Would not create substantial or widespread adverse impacts within the
region

Emissions from the source being controlled exceed a de minimis
threshold, proposed as 0.1 tons per day

An explanation of these criteria is given in succeeding sections.

Implementation Date

EPA has traditionally instructed regions to evaluate RACM measures on
their ability to advance the region’s attainment date. This means that
implementation of a measure or a group of measures must enable the
region to reduce ozone levels to the 84 ppb required to attain the
eight-hour ozone standard at least one year earlier than expected. As
the Cecil County, Maryland/Wilmapco region currently expects to reduce
ozone levels to 84 ppb during the 2009 ozone season, any RACM measures
must enable the region to meet the 84 ppb standard by May 1, 2008, the
beginning of the 2008 ozone season.

Enforceability

When a control measure is added to a SIP, the measure becomes legally
binding, as are any specific performance targets associated with the
measure. If the state or local government does not have the authority
necessary to implement or enforce a measure, the measure is not
creditable in the SIP and therefore cannot be declared a RACM. A measure
is considered enforceable when all state or local government agencies
responsible for funding, implementation and enforcement of the measure
have committed in writing to its implementation and enforcement.

In addition to theoretical enforceability, a measure must also be
practically enforceable. If a measure cannot practically be enforced
because the sources are unidentifiable or cannot be located, or because
it is otherwise impossible to ensure that the sources will implement the
control measure, the measure cannot be declared a RACM. One exception is
voluntary measures, such as those implemented under EPA’s Voluntary
Measures Guidance.

Technological Feasibility

All technology-based control measures must include technologies that
have been verified by EPA. The region cannot take SIP credit for
technologies that do not produce EPA-verified reductions.

Economic Feasibility and Cost Effectiveness

EPA guidance states that regions should consider both economic
feasibility and cost of control when evaluating potential RACM measures.
Therefore, the Cecil County/Wilmapco region has specified a
cost-effectiveness threshold for all possible RACM measures. Measures
for which the cost of compliance exceeds this threshold will not be
considered RACM.

In setting this threshold, the region took into consideration two major
factors. First, EPA has issued guidance regarding the relationship
between RACT and RACM. In its RACM analysis for the Dallas/Forth Worth
nonattainment area, EPA states:

“RACT is defined by EPA as the lowest emission rate achievable
considering economic and technical feasibility. RACT level control is
generally considered RACM for major sources.”

In Cecil County, installation of Reasonably Available Control Technology
(RACT) costs is as low as approximately $3,500 per ton.  The region
proposes a threshold of $3,500-$5,000 for cost effectiveness.

Substantial and Widespread Adverse Impacts

Some candidate RACM measures have the potential to cause substantial and
widespread adverse impacts to a particular social group or sector of the
economy. Due to environmental justice concerns, measures that cause
substantial or widespread adverse impacts will not be considered RACM.

De Minimis Threshold

In the General Preamble, EPA allows regions to exclude from the RACM
analysis measures that control emissions from insignificant sources and
measures that would impose an undue administrative burden. Under
moderate area RACT requirements, the smallest major source subject to
RACT emits 50 tpy (however, MDE considered 25 tpy sources), or
approximately 0.1 tpd.  Following these requirements and the precedent
set by the San Francisco RACM analysis, the region will not consider
control measures affecting source categories that produce less that 0.1
tpd NOx or VOC emissions.

Advancing Achievement of 84 ppb Standard

In order for measures to be collectively declared RACM, implementation
of the measures must enable the region to demonstrate attainment of the
85 ppb ozone standard one full ozone season earlier than currently
expected. As discussed in this SIP document and the relevant appendices
Cecil County currently expects to demonstrate attainment in 2009.
Therefore, any RACM measures would need to enable the region to meet the
84 ppb standard during the 2008 ozone season.

Intensive and Costly Effort

When considered together, the implementation requirements of any RACM
measures cannot be so great as to preclude effective implementation and
administration given the budget and staff resources available to Cecil
County.

7.2 RACM Measure Analysis

Analysis Methodology

The sources of strategies analyzed for the Cecil County include the
following:

Clean Air Act Section 108(f) measures (Transportation Control Measures)

Transportation Emissions Reduction Measures (TERMs) listed in recent
Transportation Improvement Programs (TIPs) for the Metropolitan
Baltimore and Washington DC regions

Measures identified through a review of emission reduction strategies
report prepared for the Baltimore Metropolitan Council

Measures considered in Washington, Atlanta and Houston RACM analyses

Analysis Results

Appendix E provides lists (in tabular form) organized by source sector,
of potential measures evaluated against the RACM criteria.  Each
specific RACM criteria was reviewed for each individual measure
identified on the lists.

Based on this analysis none of the measures reviewed were identified as
RACM for Cecil County.

7.3 RACM Determination

Though the measures listed in Appendix E did not meet the criteria for
RACM, many of the measures are worthwhile measures that reduce
emissions. These measures will be considered potential control measures
for future SIPs prepared for Cecil County.

References

US EPA, “State Implementation Plans; General Preamble for the
Implementation of Title I of the Clean Air Act Amendments of 1990”,
(57 FR 13498), April 16, 1992.

US EPA Region VI, “Reasonably Available Control Measures (RACM)
Analysis for the Dallas/Fort Worth Ozone Nonattainment Area”, December
2000.

Bay Area Air Quality Management District, Metropolitan Transportation
Commission and Association of Bay Area Governments, “Bay Area 2001
Ozone Attainment Plan,” October 24, 2001, Appendix C.

 E.H. Pechan & Associates, Inc., “ Review of Emission Reductions
Strategies”,

          December 8, 2006.

8.0 Mobile Source Conformity

Transportation conformity ("conformity") is a provision of the Clean Air
Act that ensures that Federal funding and approval goes to those
transportation activities that are consistent with air quality goals.
Conformity applies to transportation plans and projects funded or
approved by the Federal Highway Administration (FHWA) or the Federal
Transit Administration (FTA) in areas that do not meet or previously
have not met air quality standards for ozone, carbon monoxide,
particulate matter, or nitrogen dioxide.

In order to balance growing metropolitan regions and expanding
transportation systems with improving air quality, EPA established
regulations ensuring that enhancements to existing transportation
networks will not impair progress towards air quality goals.  Under the
Clean Air Act Conformity Regulations, transportation modifications in a
nonattainment area must not impair progress made in air quality
improvements.  These regulations, published in EPA's Transportation
Conformity rule on November 24, 1993 in the Federal Register and amended
in a final rule signed on July 31, 1997, require that transportation
modifications "conform" to air quality planning goals established in air
quality SIP documents.  The 1997 amendments were followed by further
amendments in 2002 and 2004.

In essence, this SIP submission includes mobile emissions budgets for
NOx and VOC.  These budgets, once found adequate by EPA, shall be used
in all conformity documents for Cecil County.  In order for a
transportation plan to “conform” the estimated emissions from the
transportation plan can’t exceed the emissions budgets set via this
SIP submission.  If the estimated emissions are shown to exceed the
budget then mitigation measures must be taken to ensure emissions will
not exceed the emission budgets.

Responsibility for Making a Conformity Determination

The policy board of a Metropolitan Planning Organization (MPO), in
consultation with the Maryland Department of Transportation (MDOT) and
MDE, is responsible to formally make a conformity determination on its
transportation plans and transportation improvement programs (TIPs)
prior to submittal to the FHWA and FTA for review. The USEPA also may
review and comment on proposed conformity determinations.

If a particular transportation plan’s projected emissions exceed the
mobile emissions budget, the MPO has a variety of mitigation options to
reduce emissions. These may include, but are not limited to, specific
transportation emission reduction measures such as HOV lanes, transit
enhancements, bicycle lanes, diesel retrofits, and idling reductions.

The Safe, Accountable, Flexible, Efficient Transportation Equity Act: A
Legacy for Users (SAFETEA-LU) was enacted on August 10, 2005.  Under
this act, amendments were made to the transportation conformity rules
(Section 6011 of the Act), which required states that have nonattainment
areas like Maryland to revise their existing transportation conformity
SIPs.  Maryland submitted a revised transportation conformity SIP to
USEPA in February of 2007.   Because of changes mandated by SAFETEA-LU,
conformity determinations have to be done at least every four years
instead of the previous three years.

When a positive conformity determination is not made according to the
required frequency, or in the event that emission mitigation can’t be
agreed upon, a nonattainment area is in conformity “lapse”. This
means that Federal transportation funds allocated to the state, which
contains the lapsed nonattainment area, can only be used for the
following kinds of projects:

TCMs in Approved SIPs;

Non-Regionally Significant Non-federal Projects;

Regionally Significant Non-federal Projects - only if the project was
approved by all necessary non-federal entities before the lapse. (See
Approval of a Regionally Significant Non-Federal Project by a
Non-Federal Entity later in this Chapter.)

Project phases (i.e., design, right-of-way acquisition, or construction)
that received funding commitments or an equivalent approval or
authorization prior to the conformity lapse.

Exempt Projects - identified under 40 CFR §93.126and 40 CFR §93.127;
and,

Traffic Synchronization Projects - however, these projects must be
included in subsequent regional conformity analysis of MPO's
transportation plan/TIP under 40 CFR §93.128.

The amount of federal funding a state receives is not reduced but such
funds are restricted until the area can again demonstrate conformity.

8.1 Mobile Emissions Budget and the Wilmington Region Transportation
Conformity Process (includes Cecil County)

Mobile source emissions for Cecil County’s portion of the long-range
transportation plan known as the Regional Transportation Plan (RTP 2025-
DRAFT RTP 2030), and the three-year Transportation Improvement Program
(TIP) cannot exceed the mobile emissions budget set in this SIP.  The
RTP and the TIP are developed by the Wilmington Area Planning Council
for Cecil County, Maryland and New Castle County, Delaware. The
transportation plans are required to conform to the mobile budget
established in the SIP for the short-term TIP years, as well as for the
forecast period of the long-range plan, which must be at least twenty
years.  Separate and individual mobile emissions budgets are created for
Maryland and Delaware.

In Cecil County, modifications to the existing transportation network
are advanced through the Wilmington Area Planning Council (WILMAPCO) by
state and local transportation agencies through periodic updates to the
Regional Transportation Plan (RTP) and TIP.  The TIP is updated annually
for the region and includes transportation modifications and
improvements on a three-year program cycle. The latest draft TIP is for
fiscal years 2008-2011. Pursuant to the conformity regulations, the RTP
and TIP must contain analyses of the motor vehicle emissions estimates
for the region resulting from the transportation improvements.  These
analyses must show that the transportation improvements in the TIP and
the plan do not result in a deterioration of (conform to) the air
quality goals established in the SIP.

8.2 Budget Level for On-Road Mobile Source Emissions

As part of the development of this SIP, the MDE formally establishes an
8-hour ozone mobile source emissions budget.  This budget will be the
benchmark used to determine if the region's long-range transportation
plan (RTP) and three-year transportation improvements program (TIP)
conform to the SIP.  Under EPA regulations the projected mobile source
emissions for 2008 (for purposes of meeting the CAA requirements related
to reasonable further progress) and 2009 (the region’s attainment
ozone season) become the mobile emissions budgets for the region unless
MDE takes actions to set other budget levels.

Modeling and Data

The 2008 and 2009 mobile emissions inventories are calculated using the
following models and tools: EPA’s MOBILE6.2, the Highway Performance
Monitoring System  (HPMS) model, and the Upper Eastern Short
Transportation Model. A detailed explanation of the models and the
emission estimating methodology can be found in Appendix F.

The mobile emissions budget for 2008 Reasonable Further Progress and
2009 attainment are based on the projected 2008 and 2009 mobile source
emissions accounting for all the mobile control measures and projected
regional growth.

Reasonable Further Progress Mobile Budgets

The mobile emissions budgets for the 2008 Reasonable Further Progress
are based on the projected 2008 mobile source emissions accounting for
all mobile control measures. The mobile emissions budgets for the 2008
Reasonable Further Progress, based upon the projected 2008 mobile source
emissions accounting for all the mobile control measures, are:

2008 RFP Mobile Budgets for the Cecil County Nonattainment Area

VOC (TPD)	2.3

NOx (TPD)	7.9

Attainment Year Mobile Budgets

The mobile emissions budgets for the 2009 attainment year are based on
the projected 2009 mobile source emissions accounting for all mobile
control measures. The mobile emissions budgets for the 2009 Attainment
Year, based upon the projected 2009 mobile source emissions accounting
for all the mobile control measures, are:

2009 Attainment Mobile Budgets for the Cecil County Nonattainment Area

VOC (TPD)	2.2

NOx (TPD)	7.3

The 2009 NOx budget is 7.3 tpd.  An adjustment has been made to the
model output to set the 2009 NOx budget.  Based on table 10-4 in Chapter
10 of this document there are 0.03 tpd of available NOx credits not
needed to satisfy the contingency measures part of this plan.  The MDE
is assigning 0.02 tpd of these additional NOx credits to the 2009 NOx
budget to create the 7.3 tpd NOx budget.

8.3 Trends in Mobile Emissions

The mobile emissions budgets for 2008 and 2009 for Volatile Organic
Compounds (VOCs) and Nitrogen Oxides (NOx) reflect a continuation of a
downward trend in mobile emissions over time. The VOC and NOx emission
levels for mobile sources provided in Section 8.2 are lower than the
most recently approved mobile budgets for Cecil County of 3.0 tons/day
VOC and 11.3 tons/day NOx from the 2003 modified Phase II Attainment
Plan for the Cecil County nonattainment area. The trend in smaller Cecil
County mobile emissions budgets from 2003 to the 2009 attainment year is
shown in the following chart.

The steady reductions in mobile emissions are attributable largely to a
series of increasingly stringent federal regulations requiring cleaner
vehicles and fuels, including the federal Tier II regulations for motor
vehicles. Trends toward reduced mobile emissions are occurring despite
the negative effects of a shift toward the use of higher-emitting, less
fuel-efficient light-duty trucks, such as SUVs instead of passenger cars
and a steady increase in population, employment and vehicle miles
traveled (VMT) within the WILMAPCO region.

The trends of increasing population, employment, and VMT are expected to
remain strong well beyond 2009. The regional cooperative forecasting
process (from the latest Regional Transportation Plan- RTP 2025)
predicts that from 2000 to 2025, regional population will grow by 19%,
households will increase by 24%, and employment will grow by 28%.
Regional VMT is predicted to still outpace these increases over the same
time period with a projected growth of 46%. These trends, however, will
not reverse the expected decline in regional mobile emissions resulting
from cleaner fuels and improved vehicle technology. The recent Tier II
passenger vehicle standards and regulations on emissions from heavy-duty
diesel vehicles and fuels are expected to produce further dramatic
reductions in VOC and NOx emissions as vehicles are replaced and
retrofitted over the next 20 years. It is important to keep in mind,
however, that despite cleaner fuels and improved vehicle technology, the
relationship between land use planning, transportation, and air quality
is important for long-term air quality goals.

9.0  Moderate Area Plan Commitments

Achieving the results shown in this Plan requires a commitment to
implement the regulatory measures upon which the plan is based.
Maryland (Cecil County) is taking action to implement regional and local
measures to effectively reduce ozone transport throughout the
Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ
Nonattainment Area.  Tables 9-1 through 9-5 provide information on the
implementation of each measure.

9.1 Schedules of Adopted Control Measures

Table 9-1

Maryland (Cecil County) Schedule of Adopted Control Measures

Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ
Nonattainment Area

Control Measure

Regulation Number

Effective Date

Federally Mandated Measures

High Tech Inspections & Maintenance 	11.14.08 	1/2/95

State II Vapor Recovery Nozzle 	26.11.24 	2/15/93

Federal Tier I Vehicle Standards and new Car Evaporative Standards 	40
CFR part 86 	Model Year 1994-1996; Evap Stds. 1996

Tier 2 Motor Vehicle Emission Standards 	65 FR 6698

 	2/10/2000

Non-CTG RACT 	See Table 9-3 	-

Phase II Gasoline Volatility Controls 	<IP_ADDRESS> 	10/26/92

EPA Non-Road Gasoline Engines Rule 	40 CFR parts 90 and 91 	12/3/96

EPA Non-Road Diesel Engines Rule 	40 CFR Part 9 et al. 	Model Year
2000-2008 depending on engine size

State NOx RACT Requirements 	<IP_ADDRESS> 	5/10/93

EPA Nonroad Spark Ignition Marine Engine Rule 	40 CFR Parts 89, 90, 91
1998 Model Year

EPA Large Spark Ignition Engines Rule 	40 CFR Parts 89, 90, 91, 94,
1048, 1051, 1065, and 1068 	11/8/2002

Federal Programs

Reformulated Surface Coatings

63 FR 48849 64 FR 34997 65 FR 7736

9/11/98 6/30/99 2/16/00

National Volatile Organic Compound Emission Standards for Consumer
Products 	63 FR 48819 	9/11/98

National Low Emissions Vehicle Program 	<IP_ADDRESS> 	3/22/99

Emissions Controls for Locomotives 	63 FR 18998  	6/15/98

Heavy-Duty Diesel Engine Rule 	63 FR 54694 	12/22/97

State and Local Measures

Reformulated Gasoline (on-road) 	Federal - local opt-in 	1/1/95

Reformulated Gasoline (off-road) 	Federal - local opt-in 	1/1/95

Surface Cleaning/Degreasing for Machinery/Automobile Repair 	<IP_ADDRESS>
	6/5/95

Landfill Regulations 	<IP_ADDRESS> 	3/9/98

Seasonal Open Burning Restrictions 	26.11.07 	5/22/95

Stage I Expansion 	<IP_ADDRESS>C 	4/26/93

Expanded Point Source Regulations to 25 tpy 	<IP_ADDRESS>B(4) 	5/8/95

Graphic Arts Controls 	<IP_ADDRESS> & .18 	6/5/95 & 11/7/94

Auto and Light Duty Truck Coating Operations 	<IP_ADDRESS> 	5/22/95

Control of VOC Emissions from Vehicle Refinishing 	<IP_ADDRESS> 	5/22/95

Portable Fuel Containers Rule:  Phase I 	<IP_ADDRESS> 	1/21/02

Architectural and Industrial Maintenance Coatings Rule 	26.11.33
3/29/04

Reformulated Consumer Products Rule:  Phase I 	26.11.32 	8/18/03

Control of VOC Emissions from Cold and Vapor Degreasing  	<IP_ADDRESS>
6/5/1995

Maryland Healthy Air Act	26.11.27	Emergency Regulations Adopted 1/18/07
- Permanent Regulations to be adopted by December 2007

Industrial Adhesives and Sealants Rule	 	Prior to May 2008

Portable Fuel Containers Rule:  Phase II	 	Prior to May 2008

Reformulated Consumer Products Rule:  Phase II

Prior to May 2008

Regional Control Measures

NOx Phase II Controls 	26.11.27 & .28

26.11.29 & 30 	10/18/99

Table 9-2

Maryland (Cecil County) Non-CTG RACT

Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ
Nonattainment Area

Overall requirement in COMAR <IP_ADDRESS>G effective 4-26-93 (20: Md. R
726)

The following case-by-case RACT regulations have been adopted to ensure
consistency.

RACT Regulation

Regulation Number

Effective Date

MD Register

Plastic Parts Coating

<IP_ADDRESS>E

6-5-95

22:11 Md R 823

Definition of Gasoline to include JP-4

<IP_ADDRESS>

8-11-97

24:16 Md R. 1161

Printing on Plastic

<IP_ADDRESS>F

9-8-97

24:18 Md R 1298

Aerospace Coating Operations

<IP_ADDRESS>-1

9-22-97

24:19 Md R 1344

Yeast Manufacturing

<IP_ADDRESS>

11-7-94

21:22 Md R 1879

Expandable Polystyrene Operations

<IP_ADDRESS>

7-3-95

22:13 Md R 970

Commercial Bakery Ovens

<IP_ADDRESS>

7-3-95

22:13 Md R 970

Vinegar Generators

<IP_ADDRESS>

8-11-97

24:16 Md R 1161

Leather Coating

<IP_ADDRESS>

8-11-97

24:16 Md R 1161

Explosives and Propellant Manufacturing

<IP_ADDRESS>

8-11-97

24:16 Md R 1161

Reinforced Plastic Manufacturing

<IP_ADDRESS>

8-11-97

24:16 Md R 1162

Marine Vessel Coating Operations

<IP_ADDRESS>

10-20-97

24:21 Md R 1453

9.2 Stationary Source Thresholds

Under the moderate designation for the 8-hour ozone standard, the new
source review threshold is 50 tons per year VOC and 100 tons per year
NOx.  Maryland is committed to maintaining the Cecil County new source
review threshold at 25 tons per year for both VOC and NOx.

10.0  Contingency Measures

10.1  Contingency Overview

The Clean Air Act requires States containing nonattainment areas to
adopt contingency measures that will take effect without further action
by the State or EPA upon a determination by EPA that an area failed to
demonstrate Reasonable Further Progress (RFP) or to timely attain the
applicable National Ambient Air Quality Standards (NAAQS), as described
in section 172(c)(9).

10.2  Contingency Emission Reductions for RFP Demonstration

The Act requires the State to adopt specific contingency measures that
will take effect without further action by the State or the EPA if the
State fails to demonstrate VOC/NOx emission reductions by an additional
3% per year from 2002 through 2009 in accordance with Rate of Further
Progress Demonstrations.

The contingency measures identified by the State must be sufficient to
secure an additional 3% reduction in ozone precursor emissions in the
year following the year in which the failure has been identified. If the
shortfall is less than 3%, a contingency measure need only cover that
smaller percentage. If the shortfall is greater than 3%, the State, in
an annual tracking report to EPA, must either identify the additional
actions it will take to cure the shortfall before the next milestone or
maintain a reserve of contingency measures capable of covering a
shortfall greater than 3%. Early implementation of an emission reduction
measure to be implemented in the future is acceptable as a contingency
measure.

The RFP contingency requirement may be met by including in the SIP a
demonstration of 18% RFP and by attributing the additional 3% reduction
above the 15% requirement to specific measures. As shown in the Tables
10.1 below, the Maryland portion of the Philadelphia - Wilmington -
Atlantic City, PA - DE - MD - NJ can demonstrate 18% RFP.

Table 10.1:	RFP Contingency Measure Calculation

RFP Contingency Measure Calculation

Cecil County, MD Nonattainment Area

VOC Emissions

 	 	Formula	Tons/Day

A	2002 Base Year Inventory	 	60.52

B	Biogenic Emissions	 	42.94

C	2002 Rate-of Progress Base Year Inventory	A - B	17.58

D	FMVCP/RVP Reductions Between 2002 and 2008	 	0.69

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
16.89

F	Percent Emission Reductions for RFP

0.0700

G	Emission Reductions Required Between 2002 & 2008	E * F	1.18

H	Target Level for 2008  [TL(2008)]	C - D - G	15.71

I		Contingency Percentage

3.00%

J	Contingency Emission Reduction Requirements	D * I	0.51

K	Contingency Target Level (15% + 3% Contingency)	H - J	15.20

L	2008 Controlled Emission Level Obtained

14.65

RFP Contingency Measure Calculation

Cecil County, MD Nonattainment Area

NOx Emissions

 	 	Formula	Tons/Day

A	2002 Base Year Inventory	 	17.40

B	Biogenic Emissions	 	0.00

C	2002 Rate-of Progress Base Year Inventory	A - B	17.40

D	FMVCP/RVP Reductions Between 2002 and 2008	 	2.19

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
15.21

F	Percent Emission Reductions for RFP

0.0800

G	Emission Reductions Required Between 2002 & 2008	E * F	1.22

H	Target Level for 2008  [TL(2008)]	C - D - G	13.99

I		Contingency Percentage

0.00

J	Contingency Emission Reduction Requirements	D * I	0.00

K	Contingency Target Level (15% + 3% Contingency)	H - J	13.99

L	2008 Controlled Emission Level Obtained

11.05

Surplus Reductions from Existing Measures

Some emission control strategies listed to meet the 2008 target level
are expected to result in more emission reductions than are needed to
meet the requirements. If other measures fail to meet expected
reductions, the excess from the following measures will be used to make
up the difference:

NONROAD MODEL

OTC - Portable Fuel Container Phase 1 and Phase 2

OTC - Architectural Surface Coatings

OTC – Commercial and Consumer Products

Railroad Locomotives Tier 2

On-Road MOBILE

10.3  Contingency Emission Reductions for Failure to Attain

The Clean Air Act requires nonattainment areas to implement control
measures necessary to meet the federal air quality standards.  Through
analysis and modeling a state demonstrates attainment based the
implementation of a State Implementation Plan.  If a nonattainment area
does not attain the federal standard by the prescribed attainment date
then the nonattainment area is required to implement contingency
measures within one year of a federal register notice that the area did
not meet its attainment date.

The attainment date for the Philadelphia Nonattainment Area including
Cecil County is June 15, 2010.  However, attainment of the standard is
based on the three-year design value that averages the ozone seasons of
2007, 2008, and 2009.  Therefore, the 2009 design value is the marker by
which attainment will be judged.  States will be notified if they did
not meet the 8-hr Ozone standard in 2010 based on a review of the 2009
design value.  One year from the date of notification the identified
contingency measures must be in fully implemented.  This means that
contingency measure must provide emission reductions in the 2011
timeframe to meet the contingency requirements.

The attainment contingency requirement can be met by demonstrating that
emission reduction benefits from specific measures occurring after 2009
meet or exceed 3% of the Adjusted 2002 Base Year inventory. As shown in
the Tables 10.2, 10.3, and 10.4 below, Cecil County can demonstrate
compliance with the Failure to Attain Contingency Measure Requirements.
The future benefits from existing control measures, calculated between
2011 and 2009, are shown in Table 10.2.  The VOC reduction requirement
is shown in Table 10.3.   The NOx reduction requirement is shown in
Table 10.4.

Table 10.2:	Failure to Attain Contingency Measure Benefit Calculation

Failure to Attain Contingency Measure Benefit Calculation

Cecil County, MD Nonattainment Area

Future Benefits from Existing Measures

	2009 Controlled

Emissions

2011 Controlled

Emissions

Benefits

(tpd)

Control Measure	VOC	NOx

VOC	NOx

VOC	NOx

OTC – PFC	0.42	0.00

0.26	0.00

0.15	0.00

Nonroad Model	7.20	2.14

6.69	2.05

0.50	0.09

Railroads (Tier 2)	0.03	0.43	 	0.03	0.41

0.00	0.02

TOTAL BENEFITS

	0.65	0.11

Table 10.3:	Failure to Attain VOC Emission Reduction Requirement
Calculation

Contingency Measure Calculation

Cecil County, MD Nonattainment Area

VOC Emission Reduction Requirements

 	 	Formula	Tons/Day

A	2002 Base Year Inventory

60.52

B	Biogenic Emissions

42.94

C	2002 Rate-of Progress Base Year Inventory	A - B	17.58

D	FMVCP/RVP Reductions Between 2002 and 2008

0.69

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
16.89

F		Contingency Percentage

2.50%

G	Contingency Emission Reduction Requirements	E * F	0.42

	REDUCTIONS ACHIEVED

0.65

Table 10.4:	Failure to Attain NOx Emission Reduction Requirement
Calculation

Contingency Measure Calculation

Cecil County, MD Nonattainment Area

NOx Emission Reduction Requirements

 	 	Formula	Tons/Day

A	2002 Base Year Inventory

17.40

B	Biogenic Emissions

0.00

C	2002 Rate-of Progress Base Year Inventory	A - B	17.40

D	FMVCP/RVP Reductions Between 2002 and 2008

2.19

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
15.21

F		Contingency Percentage

0.50%

G	Contingency Emission Reduction Requirements	E * F	0.08

	REDUCTIONS ACHIEVED

0.11

As identified above there are 0.03 tpd of additional credit under the
NOx contingency plan.  As stated in Section 8.2, the MDE has allocated
0.02 tpd of this additional NOx to the 2009 NOx mobile budget.

11.0 Weight of Evidence Attainment Demonstration

The approach to attainment demonstration taken by MDE considers the
cumulative body of science with respect to ambient ozone concentrations
in the Baltimore 8-hour ozone non-attainment area.  MDE has employed an
ensemble approach to the attainment demonstration comprised of numerous
technical tools including rigorous data analysis, observations, and
modeling.  The weight of evidence produced by MDE features contributions
from institutions with a plethora of expertise in air quality,
atmospheric chemistry, and meteorology.  The institutions include The
University of Maryland Department of Atmospheric and Oceanic Science,
The Pennsylvania State University Department of Meteorology, The Howard
University Department of Physics, The University of Maryland at
Baltimore County Department of Physics, and The University of Maryland
Center for Environmental Science at Frostburg University.  As academic
centers, these institutions have published peer-reviewed journal
articles in periodicals of the atmospheric sciences.  MDE has relied
heavily on such publications for the analysis presented in the weight of
evidence.  Highly qualified, private consultants, including SAIC and
Environ provided additional contributions to the weight of evidence.

An important distinguishing characteristic of the attainment
demonstration approach taken by MDE is not only the overall assembly of
analysis, observations, and modeling, but also the ensemble focused
solely on three-dimensional photochemical grid modeling.  Whereas the
EPA guidance emphasizes a single design value from a single modeling
simulation as the core of an attainment demonstration, the preponderance
of atmospheric science knowledge shows intelligent use of models should
consider all of the model uncertainties and biases, include multiple
simulations, and ultimately produce, not a single design value, but a
range of predicted future design values.  The ensemble approach is
analogous to how a meteorologist determines a precipitation forecast.
The meteorologist looks at multiple meteorological models, considers
uncertainties and biases of each model, reviews circumstances the model
may not account for, determines if there are any other outside
extenuating factors, and finally ascertains a range of possible
outcomes.  This range is then delivered to the forecast audience.
Similarly, the MDE ensemble approach to weight of evidence modeling
provides a comprehensive evaluation of model performance for various
scales of time, area, height, and chemistry.  Based on the sensitivity
of the model under the evaluation schemes, a range of predicted 2009
8-hour ozone design values is forecasted for every monitoring site in
the Philadelphia non-attainment area.

The net result of applying techniques of data analysis, observations,
and modeling in the weight of evidence is a favorable indication for
successfully attaining the 8-hour ozone NAAQS in 2009 for Cecil County,
Maryland and for the area presently classified as the Philadelphia
non-attainment area.  Figure 11.0.1 shows the weight of evidence range
of probable design values for 2009 for all sites in the state of
Maryland.  No single value is provided for each site; instead, a range
is provided in order to more accurately represent the expected accuracy
of the modeling exercises.  The fundamental knowledge gained through
comparisons to observations, analysis of trends, and sensitivity model
runs resulted in the ranges put forth in Figure 11.0.1.  All sites in
Maryland show attainment of the 8-hour ozone NAAQS of 85 ppb for 2009.

Figure 11.0.1	Range of probable 2009 8-hour ozone design values for all
sites in Maryland

11.1  Ambient Air Monitoring Measurements and Trends

Measurements from surface monitoring stations provide the most
fundamental indication of air quality improvement in the Baltimore
non-attainment area.  Basic trends of ozone from the network of monitors
show continuously improving air quality Maryland and the Baltimore NAA
with respect to multi-year design values, annual exceedance day counts,
24-hour daily peak concentrations, single-hour concentrations, spatial
area, warm weather days when ozone is usually highest, and finally with
respect to ozone precursor trends.

The Ambient Monitoring Network

MDE operates a relatively dense network of ozone monitoring stations,
which has enabled the collection of high resolution ozone data on
various scales of time and space.  Figure 11.1.1 shows maps of the
ambient ozone monitoring network for Maryland, the Mid-Atlantic, and the
Eastern U.S.  Despite the small size of Maryland, MDE operates a
relatively dense network of ozone monitors.  Comparing the spatial
density of monitoring sites on a wider domain of the Mid-Atlantic region
shows that Maryland has no large expanses without monitors, like
Virginia, West Virginia, and Pennsylvania.  An even larger perspective
over the entire Eastern U.S. reveals that Maryland is actually covered
by one of the more dense monitoring networks due to the required
monitoring associated with the cluster of large metropolitan areas
extending from Richmond, VA through New York, NY.

The code of federal regulations requires four ozone sites for a
metropolitan statistical area of  > 10 million people for an 8-hour
ozone non-attainment area (40CFR58 Appendix D §4.1).  MDE currently has
seven ozone sites deployed in the Baltimore NAA and one site in the
Cecil County, Maryland portion of the Philadelphia NAA.  Due to
logistical reasons, slight changes are made in the deployment of sites
over the years, such as the unavoidable relocation of the Fort Meade
monitoring site due to the U.S. military’s need for additional space
on the grounds of the Fort Meade military post.  MDE was fortunate to
find a new location for the site at Beltsville, where inter-agency
collaborations and opportunities for long-term studies are more viable.
On the whole, the number of sites remains relatively constant.

Ozone Trends

Ozone concentrations exhibit an improving air quality trend on multiple
temporal scales.  Perhaps the simplest regulatory measure of improving
air quality is the downward trend in 8-hour ozone design values for the
sites in Maryland.  Design values offer the benefit of a multi-year
metric, which removes the statistical bias of single high values by
taking the fourth highest value of three consecutive years and averaging
those values together.  Figure 11.1.2 displays the decreasing trend of
8-hour ozone design values in Maryland.  The trend is a good fit to the
data with an R2 of ~0.4 and a slope of –0.7 ppb / year.  The last
three years highlight the disproportionate benefit of the NOx SIP Call
when regional controls were put in place between 2003 and 2004.

The downward trend in 8-hour ozone concentrations on an annual basis is
highlighted in Figure 11.1.3 by showing the number of 8-hour ozone
exceedance days per year.  This trend is also a good fit with an R2 of
~0.5 and a steeper declining slope of –1.4 days / year.  Since 2002,
an average of 17.5 days per year have experienced 8-hour ozone
concentrations ( 85ppb or in other words 2.5 weeks, which is a sharp
contrast to the 2 months worth of exceedance days, which existed in the
1980s.

Taking yet another step down in temporal scales brings the study of
trends to the daily scale.  Average daily peak 8-hour ozone is shown in
Figure 11.1.4.  In order to see a clearer picture of the trends without
the noise of short-term fluctuations, the data are grouped in four-year
bins.  The methodology of choosing bins is carried out in reverse
chronological order, beginning with the first four-year bin of
2003-2006, the NOx SIP Call years.  Scientific consensus is that ozone
concentrations in the eastern U.S., outside of large urban areas, are
NOx-limited.  As a result, reductions in region-wide NOx emissions
should reduce the overall background ozone concentrations.  Local
emissions and photochemistry will still lead to short-term spikes in
ozone, often ( 85 ppb, but these spikes will occur on top of a lower
base-level of ozone.  The magnitude of each individual ozone spike
should also have reduced amplitude from the base-level.  Such a change
in the base-level of ozone was created by the NOx SIP Call and is
demonstrated in Figure 11.1.4.

Panel C – Mid-Atlantic Ozone Network

Figure 11.1.1	Maps of ozone monitoring sites (inverted green triangles).
 Panels A, C, and D show sites active during 2006.  Panel B shows sites
active during the period of 2002-2006.  There are 17 ozone monitoring
sites in the state of Maryland, a dense network for a relatively small
state.

Figure 11.1.2	Trend in 8-hour ozone design values per year for all
Maryland sites.

	The declining trend is a sign of improving air quality.

Figure 11.1.3	Trend in 8-hour ozone exceedance days per year for all
Maryland sites.  The declining trend is an indicator of improving air
quality.

Figure 11.1.4	Trends in average daily peak 8-hour ozone for all Maryland
sites binned by four-year periods.  The red brace and arrow indicate
improving air quality shown by the decreasing trend of average daily
peak 8-hour ozone.  Each trend line is fourth order.

Continuing in reverse chronological order, each of the prior bins also
consisted of a four-year period for the sake of consistency.  The most
important feature of Figure 11.1.4 is the steady decline in the trend of
each bin, indicated by the red arrow.  The part of the summer when peak
ozone concentrations occur (June-August) is exactly when the greatest
benefit is seen with reductions in the daily peak 8-hour ozone.  The
improving trend in 1999-2002 (green) is partially due to meteorology
because the summers of 2000 and 2001 were not conducive to photochemical
formation as temperatures were cooler than normal, precipitation was
more prevalent, and the synoptic scale systems rarely created long-lived
high pressure centers over the South Eastern U.S. which typically plays
a large role in high ozone episodes.  The improving trend in 2003-2006
(blue) shows another marked decrease in ozone values, a sign of the
valuable impact of the NOx SIP Call.

Not only have ozone concentrations been steadily declining during the
part of the summer when ozone production is greatest, but ozone
concentrations have also been steadily declining during the part of each
day when ozone production is greatest.  Being a photochemical pollutant,
ambient ozone concentrations reach their peak during the afternoon when
the sun angle is high and temperatures are at their warmest.  Figure
11.1.5 shows the diurnal trend in ozone from 1993 to 2006.  The years
are binned by 3-year rolling averages in order to eliminate the noise of
hourly fluctuations present in the raw data.  The steady progression
from each rolling average to the next shows an undeniable improvement of
air quality.  The red arrow indicates the decline of ozone
concentrations.  The last three rolling averages (yellow, gray, black)
experienced a distinct decline in magnitude of hourly ozone after the
NOx SIP Call.

Figure 11.1.5	Trend in diurnal ozone by 3-year rolling averages for all
Maryland sites from the summers (April 1 – October 31) of 1993 through
2006.  The red brace and arrow indicate improving air quality shown by
the decreasing trend of peak mid-day hourly concentrations.

While various temporal scales have shown declining concentrations of
ozone over the year, one of the most concise methods for displaying
year-to-year improvement in air quality is to map interpolated ozone
concentrations across a wide domain.  Figure 11.1.6 shows the trend in
the spatial extent of 8-hour ozone design values ( 85ppb from 1995 to
2006.  Improving air quality is exhibited by the steady decrease of the
spatial extent as well as the magnitude of design values that are (
85ppb.  The maps indicate the region as a whole has been experiencing
continuous progress towards attaining the NAAQS for ozone.  Substantial
improvements are observed after 2004 as indicated by the shrinking
spatial extent of the area ( 85ppb and the decrease in regional maximum
8-hour ozone design values.  The maps were created using Tension Spline
interpolation in ESRI ArcGIS with the Spatial Analyst extension.
Tension Spline interpolation enforces precise representation of all
observed measurements and employs smooth contours that avoid falsely
characterizing the spatial extent of the design values.  As with all
interpolation techniques there are inevitably some portions of the
domain that will be misrepresented by either over or under estimations.
Portions of the domain over the Chesapeake Bay appear to have estimates
on the high end, weighting the Washington-Baltimore corridor sites more
heavily than the DEL-MAR-VA peninsula where sites are in attainment.

  Figure 11.1.6	1995-2006 improving trend exhibited by decreasing
spatial extent and magnitude of 8-hour ozone design values ( 85ppb.

The approach to trends thus far has focused entirely on the ozone
concentrations themselves.  A more comprehensive look at ozone trends
must also consider meteorology and precursors.  Ozone is a photochemical
pollutant and as such, it is highly dependent upon meteorological
conditions.

Temperature Adjusted Ozone Trend

The data shown in Figure 11.1.7 provide insight to the trend of 8-hour
ozone with respect to temperature.

Figure 11.1.7	Improving air quality in Maryland is shown by the downward
linear trend (black line) of the difference between (blue line) the
number of 8-hour ozone exceedance days per year (green bars) and the
number of days with a daily maximum temperature > 90(F per year at BWI
(red bars).  The time period is 1981-2006.

Temperature is the single strongest environmental predictor of ozone
concentrations, as such there has historically been a strong correlation
between the number of 8-hour ozone exceedance days per year and the
number of days with a daily maximum temperature > 90(F per year at BWI.
In fact, in the early 1980’s the number of exceedance days was
typically double the number of 90(F days.  This statistic has steadily
changed through, so that in 2006 the ratio was the exact opposite with
the number of 90(F days doubling the number of exceedance days.  The
trend in the difference between the two counts (black line) has an R2 of
0.6 and a downward slope of –1.3.  Despite stable numbers of 90(F
days, ambient ozone concentrations continue to experience a continuous
downward trend reflecting improvements in air quality.  Besides ozone
itself and meteorology, the third important subject which should be
explored by trends is precursors to ozone formation.

Ambient Ozone Precursor Trend

As described in Chapter 2, the precursors to ozone formation include
VOCs and NOx.  VOCs are a somewhat difficult to depict in terms of
simple trends because the list of VOCs is so large.  MDE collects 56
species of VOCs as part of the PAMS (Photochemical Assessment Monitoring
Sites) network and a separate list (with some commonality) of 61 Toxic
VOCs.  VOC measurements have uniformly experienced declines in
concentrations since 1994 due to the reforumulated gasoline rule,
hydrocarbon reductions for Ozone, and also some associated benefits
since 1990s restrictions on CFC (chlorofluorocarbon) emissions.  NOx on
the other hand, is more simply analyzed and it is widely available.
Based on observations, ozone concentrations vary linearly with
integrated upwind NOx emissions (Appendix G-1).  A given percent
reduction of NOx should result in an equal percent reduction of ozone.
NOx is measured by the same trace gas instrumentation used to
simultaneously measure ambient NO and NO2.  NO2 is commonly measured to
show compliance with the NO2 NAAQS.  Figure 11.1.8 displays the
decreasing trend of NOx for the BNAA since 1993.

Figure 11.1.8	Trend in diurnal NOx by 3-year rolling averages for all
sites in Maryland from the summers (April 1 – October 31) of 1993
through 2006.  The red brace and arrow indicate improving air quality
shown by the decreasing trend of peak hourly concentrations.  Instrument
calibration occurs during the data gap at 2:00 AM EST.

Supplemental Monitoring Initiatives

Monitoring in order to show compliance with the NAAQS and in order to
quantify exposure while protecting the health of the public and
environment, is the first goal of ambient air quality monitoring.  As
such, the CFR requirements focus on monitoring for exposure and
monitoring for background concentrations.  MDE takes great care to go
beyond the CFR requirements to ensure ambient concentrations are being
measured in rural, suburban, and urban locales.  17 ozone monitoring
sties are operated in Maryland and 7 of them lie within the Baltimore
NAA where only 5 monitors are required by the CFR.  While monitoring for
compliance and exposure does allow the state to ensure healthy air
quality is maintained, monitoring for compliance and exposure does
little to explain why poor air quality episodes develop.  In fact,
compliance and exposure monitoring tells virtually nothing about the
source of an air mass and where the emissions originated.  In order to
discover where poor air quality is coming from, monitoring has to be
conducted with an eye towards culpability.

MDE dedicates large resources to monitoring for culpability in order to
discover the origins of poor air quality episodes, so that the problem
may be addressed at its source.  Tracking the history of air parcels
involves taking measurements from above the ground surface and deploying
instrumentation into the atmosphere at varying heights.  In this vane,
MDE has created several atmospheric profiling initiatives including
various platforms:  aircraft, ozonesonde balloons, RADAR (Radio
Detection And Ranging), LIDAR (LIght Detection And Ranging), and
high-elevation, mountain-top sites.  Figure 11.1.9 shows photographs of
the first four platforms.

Panel A

	Panel B

Panel C

Panel D

Figure 11.1.9	Supplemental atmospheric profiling initiatives supported
by MDE.

	A. Aircraft, B. Ozonesonde Balloon, C. RADAR, D. LIDAR

Data collected from these projects allow MDE to understand interstate
pollutant transport and to state the case for equitable emission control
strategies across state boundaries.  The data products are priceless
tools for examining model performance, analyzing air quality episodes,
and educating the general public.  The remainder of this section is
dedicated to describing each of these supplemental monitoring
initiatives, each of which serves an important role in quantifying the
degree of interstate air pollutant transport coming into Maryland.

Aircraft

MDE has contracted with the University of Maryland since 1995 to make
aircraft profile spirals over locations throughout the Mid-Atlantic and
as far away as North Carolina and Vermont.  Measurements include trace
gases and aerosol characteristics from 100m – 4,000m in altitude in
variable intervals with 10-second resolution.

Ozonesonde Balloons

MDE has contracted with Howard University since 2005 to make ozonesonde
balloon profiles over Beltsville, Maryland.  Measurements include
temperature, relative humidity, wind speed, wind direction, and ozone
from 0m – 32,000m in altitude at variable intervals with 1-second
resolution.  The ozonesonde is made up of two paired modules:  A
wet-chemistry ozone-sensing module and a GPS rawinsonde
meteorology-sensing module.

RADAR

MDE owns and operates two radar wind profilers.  One was originally
deployed in 1998 at Fort Meade, Maryland.  It was subsequently moved to
Beltsville, Maryland in 2005.  During the same year a second radar wind
profiler was purchased by MDE and deployed at the Piney Run monitoring
site near Frostburg, Maryland.  The RADAR measures wind speed, wind
direction, and virtual temperature from 120m – 4,000m in altitude in
intervals of 100m with 15-minute resolution.  RADAR emits
electromagnetic energy and detects shifts in the backscattered energy,
which mathematically translate to information about the winds and
temperature in the atmosphere.

LIDAR

MDE has contracted with the University of Maryland at Baltimore County
since 2005 to measure aerosols over Catonsville, Maryland.  Measurements
include aerosols scattering from 0m – 10,000m in altitude in 1m
intervals with 1-minute resolution.  LIDAR emits laser light and detects
changes in the backscattered light which mathematically translate to
information about the aerosol content and dynamics in the atmosphere.

High-Elevation Mountain-Top Sites

MDE deployed a high-elevation, mountain-top surface monitoring site in
2004 called Piney Run, located near Frostburg, Maryland.  The site sits
along the western boundary of Maryland in a rural setting with minimal
local emissions.  The site serves as a front-line indicator of westerly
transport arriving in Maryland and fills a gap in high elevation
monitors between Methodist Hill, Pennsylvania, and Shenandoah National
Park, Virginia.

11.2  The Challenge of Interstate Transport

In terms of geography, Maryland enjoys the benefit of many natural
resources.  The state’s location on the east coast provides
considerable shoreline along the Atlantic Ocean, a wealth of fresh water
resources in the Chesapeake Bay, and in the west, high elevation access
to the Appalachian Mountains.  While there are tremendous benefits to
the state’s geographical location; there is a major challenge in terms
of air quality:  downwind interstate air pollution transport.  Maps of
the four main patterns associated with air pollution transport into
Maryland are provided in Figure 11.2.1.

Depending largely on the placement and severity of the Bermuda High
Pressure Center, the worst ozone episodes are almost always associated
with one of the four main transport patterns: Along Corridor, Northerly,
Westerly, and Pre-Frontal.  The concentration of ozone in each of the
upwind areas determines just how severe of an impact the interstate air
pollution transport will have on air quality in Maryland.  All four of
the transport patterns have one thing in common:  a westerly transport
component.  Westerly transport is well documented in peer-reviewed
publications.  One such description of the role of transport in regional
ozone episodes was described by Taubman:  “Regional high ozone events
often occur when the Bermuda high strengthens and extends west into the
eastern United States.  Subsidence east of the ridge induces clear
skies, high temperatures, atmospheric stability, and stagnant winds.
These factors enhance photochemistry and inhibit vertical mixing,
thereby contributing to increased local concentrations of ozone.
Circulation around the ridge results in westerly transport of ozone and
ozone precursors from the Midwest to the eastern United States, where
they combine with local emissions."

Figure 11.2.1	The four main synoptic meteorology patterns associated
with transport of air pollution into Maryland.  The colored background
represents temperature.  The pressure is indicated by white isobars with
“H” at the center of high pressure systems.  Winds are shown as
small white arrows and general circulation is shown as large black
arrows.

Westerly Transport

Major upwind ozone precursor sources lie just beyond the borders of
Maryland in states such as West Virginia, Virginia, Pennsylvania, and
Delaware.  Long-range interstate transport also extends beyond the
adjoining states to states such as Ohio, Michigan, Kentucky, North
Carolina, and Georgia.  The direction of transport coming into Maryland
includes just about every compass direction, but the primary concern is
transport from the west where the dense number of point sources along
the Ohio River Valley has a direct impact on Maryland’s air quality on
a regular basis.

As the atmosphere exhibits no boundaries in space or time, interstate
pollutant transport occurs continuously throughout the diurnal cycle.
During the daytime when the atmospheric column is well mixed, it is
difficult to apportion the relative impact of long-range emissions
versus local emissions.  However, during the night when the atmosphere
stratifies, pollutant concentrations can sometimes become isolated above
the ozone-poor, nocturnal boundary layer in a layer referred to as the
“residual layer”.  Figure 11.2.2 shows the development of the
nocturnal residual layer where interstate transport may be frequently
observed.

Figure 11.2.2	Diagram of the atmospheric boundary layer.  The nocturnal
atmosphere stratifies into a residual layer aloft where interstate
pollutant transport may be measured.

At night during the summer when the surface cools faster than the air
above it, a temperature inversion will develop that stratifies the lower
planetary boundary layer.  Below the inversion dry deposition with the
surface, brings ozone concentrations to minimum in the “ozone-poor
layer”.  Above the temperature inversion, pollutants that were emitted
throughout the day and pollutants that continue to be injected high into
the atmosphere by tall point sources with hot buoyant plume rise, are
trapped in the residual layer.  The boundary between the residual layer
and the ozone-poor layer creates a stratified atmosphere and pollutants
travel above with laminar characteristics through the residual layer.

The residual layer creates an opportunity to observe interstate
transport before local emissions contribute to the total pollutant load.
 The obstacle is finding a way to take measurements from within the
residual layer, which is typically 300-600m above the ground surface.
MDE has utilized three separate measurement platforms to make in-situ
vertical profile observations of westerly transport within the residual
layer.  These include high elevation surface monitoring sites, ozonsonde
balloons, and aircraft.  A case is presented here from August 13, 2005
which shows the detection of residual layer ozone transported from
upwind locations into the Maryland air shed.  August 13, 2005 did
experience exceedances of the 8-hour ozone NAAQS in the Baltimore
non-attainment area; however, there are many other cases when higher
ozone concentrations have been measured.  The case is chosen as a case
study primarily because of the balloon and aircraft data availability
for the episode.  The synoptic circumstances observed do represent the
conditions that are frequently present during extended ozone episodes
such as the kind that result in being relevant to design value
calculations.  The fact that conditions for the case were so
theoretically perfect for an ozone episode is precisely why the air
quality forecasters recommended the balloons and aircraft be put into
operation for the period.

On August 13, 2005 a high pressure center was in place over the
southeastern United States (Figure 11.2.3, Panel A).

Figure 11.2.3	A.	Synoptic analysis from 7:00 AM EST of August 13, 2005.
High pressure over the south east United States, an approaching cold
front, and a lee-side trough all serve as strong indicators for an ozone
episode.

	B.	Visible Satellite imagery from 10:45 AM EST of August 13, 2005.
Cloud cover is associated with the cold front and haze is present over
much of the Mid-Atlantic.

This high-pressure system created clockwise circulation with streamlines
crossing the Ohio River Valley and carrying its point sources emissions
into Maryland.  The high-pressure circulation was reinforced by an
approaching cold front (blue line with triangles) which served to
suppress horizontal ventilation to the NorthEast.  In addition a
lee-side trough was analyzed east of the Appalachian Mountains (dashed
orange line) which typically coincides with an enhanced mesoscale
southwesterly flow within the residual layer called the Nocturnal Low
Level Jet.  Visible satellite imagery (Figure 11.2.3, Panel B) shows
haze over much of the Mid-Atlantic and cloud cover associated with the
cold front.  There are three measurement platforms, which successfully
observed residual layer transport of ozone on August 13, 2005.  The
first platform described is the network of surface monitoring sites
including some sites at high elevation.

Demonstration of Residual Layer Westerly Transport using High Elevation
Monitors

MDE forecasts air quality for the state of Maryland using not only the
network of surface ozone monitors owned and operated by MDE, but also
several monitors in surrounding states including Delaware, the District
of Columbia, Pennsylvania, Virginia, and West Virginia.  Sites from the
other states serve a supplementary function in providing data where the
geographical boundary of Maryland has made it impractical to make heavy
deployment of monitoring sites.  Figure 11.2.4, Panel A provides a map
of every sites used by the MDE air quality forecasting program during
the summer of 2005.  The topography of the map reveals that three of the
sites indicated by colored triangles lie at high elevation.  In fact the
elevation of those three sites is approximately double the height of any
other site in the domain.  The three high elevation sites are Piney Run,
Maryland, Methodist Hill, Pennsylvania, and Shenandoah National Park,
Virginia.  Figure 11.2.4, Panel B shows a plot of hourly ozone
concentrations for August 13, 2005 for every site shown in the Panel A
map.  During the night time hours of 2:00 AM – 7:00 AM EST the three
high elevation monitors exhibit a remarkably different sample of ozone
concentrations from the rest of the sites.  In fact during the night
hours, the high elevation monitors registered concentrations of ~55ppb.
On average, that is more than double the ~20ppb concentrations sampled
by the low-lying sites in the ozone-poor layer of the atmosphere.  Piney
Run (red triangle) appears to have initially begun to lie within the
ozone-poor layer of the boundary layer from 12:00 AM – 2:00 AM EST,
but it quickly soon returned to higher concentrations of ozone as the
residual layer settled down to the elevation of the monitoring station.

These important high elevation measurements show that when the morning
mixing begins, residual layer ozone may have an immediate contribution
of 55ppb to the daily ozone concentrations in Maryland.  This creates a
situation in Maryland where an ozone allotment of only 30ppb may be
produced locally before the NAAQS will be exceeded for the day.

Figure 11.2.4	A.	Topographical map of Maryland and the surrounding
states with an overlay of ozone monitoring sites used for Maryland air
quality forecasting.  Topographical shades of green represent low
elevations and topographical shades of brown represent high elevations.

		Black Circles:		Low Elevation Monitoring Sites ( < 365m )

		Colored Triangles:	High Elevation Monitoring Sites

				Red  = 781m, Green = 630m, Blue = 1,072m

 Hourly Ozone on August 13, 2005 for all sites shown in Panel A.

Demonstration of Residual Layer Westerly Transport using Ozonesonde
Balloons

The second platform used to measure residual layer ozone transport for
the case of August 15, 2005 was the ozonesonde balloon launched from
Beltsville, Maryland.  In fact, two balloons were launched during this
period, one at 6:00 AM EST and one at 2:00 PM EST.  At the 6 AM launch
(Figure 11.2.5) the nocturnal inversion is pronounced at ~ 400m in the
temperature profile (red).  The wind speed profile (blue) shows a 10m/s
local maxima between 300-1000m indicating the presence of a nocturnal
low level jet.  The wind direction (purple) confirms another jet
characteristic, veering winds from the surface to the top of the jet at
1000m.  The ozone profile (black) shows minor increases in ozone within
the LLJ.

Figure 11.2.5	Ozonesonde balloon launch at 6:00 AM EST on August 15,
2005 from Beltsville, Maryland.  Ozone is in black, temperature is in
red, wind speed is in blue, and wind direction is in purple.

Demonstration of Residual Layer Westerly Transport using Aircraft

The third platform used to measure residual layer ozone transport for
the case of August 15, 2005 was the aircraft, which made several spirals
along the western boundary of Maryland and over locations south of
western Maryland.  The spirals were flown over Luray, VA at 10:00 AM
EST, Winchester, VA at 11:00 AM EST, and Cumberland, MD at 11:45 AM EST.
 Figure 11.2.6  shows profiles from over the three locations in three
panels.  Panel A shows concentrations of almost 80ppb in the nocturnal
residual layer from 1400-1800m in height.  SO2 concentrations are
correspondingly large over the same height; however, CO shows its
largest concentrations near the surface, where mobile emissions are
trapped beneath the boundary layer.

Panel A

10:00 AM

EST

Luray

VA

Panel B

11:00 AM EST

Winchester

Panel C

11:45 AM EST

Cumberland

Figure 11.2.6	Aircraft spirals on August 15, 2005.  Ozone is in black,
temperature is in red, SO2 is in orange, and CO is in yellow.

Similar structure is observed in Panels B and C as the day progresses,
but with increased mixing of the high concentrations which broadens the
height of the localized maxima to 700-2100m in height.

Animated Google Earth Movie of Westerly Transport

All of the observations recorded by the three platforms presented in
section 11.2 are incorporated in an animated movie MDE has created for
the August 15, 2005 westerly transport case.  Additional profiles are
also included for later in the day showing the impact of transport on
the eventual concentrations of ozone in the major metropolitan corridor
including Washington, DC, Baltimore, MD, and Philadelphia, PA.  HYSPLIT
24-hour back-trajectories are plotted for every vertical profile using
the NOAA EDAS 40km data archive and modeled vertical velocity.
Additionally, the 1999 EPA NOx point source emissions inventory was used
to plot all NOx sources that emit 25 tons per day or more of NOx.
Counts of the number of point sources per state that emit 25 tons per
day or more of NOx are also presented.  The animated movie was created
using Google Earth Professional Version and was recorded and burned to
DVD.  Appendix G-2 contains the DVD.

Nocturnal Low Level Jet Transport

In addition to the large-scale westerly transport resulting from the
four synoptic meteorological patterns described at the beginning of
section 11.2, a smaller-scale transport mechanism created by mesoscale
meteorological conditions also has a significant impact on poor air
quality episodes in Maryland.  This mechanism is the nocturnal low-level
jet (NLLJ) which flow from SW to NE in the Mid-Atlantic region, parallel
to and on the lee-side of the Appalachian Mountains.  Taubman describes
the NLLJ in simple terms:

“The NLLJ occurs between 12:00 AM and 6:00 AM EST and has the
following characteristics:

Generally located between 300 and 1000 m in altitude

South-Southwesterly wind maximum in the residual layer of 10–20 m/s

NLLJ “core” with wind speed maximum greater than those in the
underlying nocturnal boundary layer and those just above, but still in
the jet

Veering winds (turning from S to W) from the surface up through the NLLJ
core

The nocturnal boundary layer provides a low-friction surface over which
the jet can travel.  This phenomenon also seems to be orographically
derived, possibly resulting from the differential heating and pressure
gradients associated with sloping terrain on the lee-side of the
Appalachian Mountains.  Pollutant transport via the NLLJ is
disproportionately important during periods of stagnation when
geostrophic winds are light.”  Figure 11.2.7 shows the synoptic
weather analysis for August 5, 2005 at 7:00 AM EST.  Much like the
westerly transport example detailed in earlier sections, August 5, 2005
also had high pressure over the southeast U.S. with a cold front
approaching from the northwest.  The pink arrow indicates the
theoretical position of the NLLJ, based upon other field studies which
documented the presence of the NLLJ in New Jersey, Pennsylvania,
Maryland, Virginia, and North Carolina.

Figure 11.2.7	Synoptic weather analysis from August 5, 2005 at 7:00 AM
EST.  The pink arrow indicates the theoretical position of the NLLJ.

The NLLJ is an important mechanism for transport for two reasons.  It
acts as a conduit for air pollutant transport and like westerly
transport, the residual pollutants within the NLLJ will mix down to the
surface when the nocturnal inversion breaks down.  Secondly, the NLLJ
creates turbulence between the ozone-poor nocturnal surface layer and
the ozone-rich residual layer during the night, which increases
nocturnal ozone exposure at the surface when benign ozone concentrations
would otherwise be expected.  There are three measurement platforms,
which successfully observed the NLLJ and associated ozone transport on
August 4-5, 2005.  In total, four independent measurements were made of
the NLLJ in this case:  RADAR, LIDAR, and two separate ozonesonde
balloons.  Figure 11.1.1 Panel A shows the location of the Beltsville
monitoring site where the RADAR is located and where the ozonesonde
balloons were launched.  The LIDAR is located in Catonsville, MD on the
campus of the University of Maryland at Baltimore County near the
intersection of three Maryland counties:  Baltimore County, Howard
County, and Anne Arundel County.  Both the RADAR and LIDAR platforms are
described simultaneously in this first portion of the case description.

Demonstration of Residual Layer NLLJ Transport using RADAR and LIDAR

The MDE RADAR in Beltsville, Maryland observed the August 4-5, 2005 NLLJ
for 8.5 hours beginning at 11:00 PM EST on August 4, 2005 and ending at
7:30 AM EST on August 5, 2005.  The top portion of Figure 11.2.8 shows a
time-height plot of wind observed by the RADAR.  Portions of the plot,
which fit the accepted fingerprints of a NLLJ are enclosed by the black,
amoeba-shaped line.  Wind speeds of 15 m/s, veering with height, were
observed throughout the jet, which was observed from 200-800 meters in
altitude.

Figure 11.2.8	The top portion of the time-height plot depicts winds from
the RADAR at Beltsville, Maryland.  The bottom portion of the
time-height plot depicts aerosol scattering from the LIDAR at
Catonsville, Maryland.  The black, amoeba-shaped, line is drawn around
the portion of the RADAR data that fits the stereotypical
characteristics of a NLLJ.  The same black shape was also overlayed on
the LIDAR data.  The timing of two ozonesonde balloon launches from
Beltsville, Maryland are also overlayed in pink, dashed lines at their
respective launch times.

The same black outline was overlayed on the LIDAR data in the lower
portion of Figure 11.2.8.  The outline provided an excellent qualitative
match to the portion of the LIDAR data exhibiting a signature of the
NLLJ, namely enhanced turbulent inhomogeneties and stratification at the
same heights and for the same period of time as the RADAR winds.  The
final piece of information in Figure 11.2.8 is the overlay of ozonesonde
balloons (pink dashed lines) at their respective launch times.

Demonstration of Residual Layer NLLJ Transport using Ozonesonde Balloons

The data collected by the two ozonesonde balloons are displayed in
Figure 11.2.9.  Panel A shows the launch at 3:30 AM EST and Panel B
shows the launch at 7:30 AM EST.  Both launches revealed fast wind
speeds (blue profiles) in the jet and veering wind directions (purple
profiles).  In the earlier launch, the jet speed is 14 m/s with a jet
core from 200-800 m in altitude.  In the later launch, the jet speed is
10 m/s with a jet core from 250-500 m in altitude.  The black profiles
of ozone in each plot show a local maximum in ozone between 500-1000 m
in altitude.  The local ozone maxima appear to be associated with the
presence of the NLLJ.  Recent, unpublished work documents secondary
nocturnal maxima occurring during the night at surface monitors when the
presence of a NLLJ is confirmed.  The magnitude of the secondary
nocturnal ozone maxima has been measured as high as 30ppb when monitored
at the surface using 10-minute average data.

Figure 11.2.9	Ozonesonde balloon data are shown as vertical profiles
through the atmosphere.  Radar winds are overlayed with the blue and
purple data points.  Two balloon launches took place on August 5, 2005.

		A.	3:30 AM EST on August 5, 2005

		B.	7:30 AM EST on August 5, 2005

Animated Google Earth Movie of Nocturnal Low Level Jet Transport

All of the observations recorded for the NLLJ case on August 4-5, 2005
are also incorporated in an animated movie created by MDE.  Additional
details are provided along with animated versions of the RADAR wind
profiles.  The animated movie was created using Google Earth
Professional Version and was recorded and burned to DVD.  Appendix G-3
contains the DVD.

Climatology of the NLLJ in Maryland

A lengthier investigation of the NLLJ over Maryland for multiple years
has been compiled in two separate reports.  Appendix G-4 contains
“Radar Wind Profiler Observations in Maryland:  A Preliminary
Climatology of the Low Level Jet” written by the University of
Maryland and Appendix G-5 contains “The Low Level Jet in Maryland:
Profiler Observations and Preliminary Climatology” written by
Pennsylvania State University.

Apportionment of Ozone Transport

The prior sections on Westerly Transport and the NLLJ provide case
studies of important transport mechanisms.  MDE has funded several
projects to take a closer look into the apportionment of ozone transport
culpability, to investigate how much ozone is transported by the
mechanisms and to discover from what states or regions the transported
ozone and ozone precursors originate.  There is strong evidence from
statistical analysis, modeling, and observations that points towards
heavy contributions of westerly transport and nocturnal low-level jet
transport to the 8-hour ozone non-attainment status in Baltimore
non-attainment area, which is often the upwind source for Cecil County.

Cumulative evidence suggests 60-80% of the 8-hour ozone non-attainment
in the Baltimore corridor is due to westerly transport.  A statistical
analysis of ozone trends by meteorological regime (Appendix G-6),
estimates that 40-64% of the 8-hour ozone concentrations at Baltimore
can be attributed to regional effects rather than localized effects that
influence only the Baltimore area.  EPA modeling found that upwind
contributions are responsible for up to 68% of the non-attainment
problem in the BNAA.  UMD completed a cluster analysis of hundreds of
aircraft profile spirals that found when the greatest cluster trajectory
density lay over the Ohio River Valley (~59% of the profiles), transport
accounted for 69–82% of the afternoon boundary layer ozone.  Under
stagnant conditions (~27% of the profiles), transport still accounted
for 58% of the afternoon boundary layer ozone.

Cumulative evidence also suggests the nocturnal low level jet plays a
role in the 8-hour ozone non-attainment status for the BNAA.
Statistical analysis reports the presence of LLJs in Baltimore results
in a 7ppb increase in ozone concentrations and a 5ppb increase in
Washington DC (Appendix G-6).  A climatological study of RADAR
observations, shows that for the period of August, 1998 to November,
2002, NLLJs occurred on 70% of Code Orange 8-Hour Ozone days and 42% of
Code Red 8-Hour Ozone days (Appendix G-5).

Using 232 aircraft vertical profiles performed in the Mid-Atlantic and
Northeast U.S. between 1997 and 2003, greater NOx emissions along back
trajectories from the aircraft profiles were positively correlated with
greater ozone mixing.  Ozone column contents during the flights were
strongly influenced by point source emissions with a slope of 61.6 ppb
ozone / (g NOx m-2 day-1) and a correlation (R2) of 0.997 (Appendix
G-1).  This shows that if upwind point source emissions are reduced,
ozone in Maryland will also be reduced at the same rate.

A study of the relative contribution of transported and local
photochemistry to the ozone data for six exceedance days in August 2002
shows that if local photochemistry were the only source of ozone, none
of the 6 days examined would have exceeded the 8-hour ozone standard
(Appendix G-7).  The effect of the transported ozone is to add ozone
early in the day and hence to expand the time interval over which the
ozone levels may exceed 85 ppbv.  All indications point to the
importance of transported upwind point source emissions on the air
quality of Maryland.  Clearly transport is a paramount consideration,
which must be account for in an attainment plan especially in modeled
simulations.

11.3  Modeled and Probable Range Attainment Demonstration

Instead of emphasizing a single design value from a single modeling
simulation as the core of an attainment demonstration, the preponderance
of atmospheric science knowledge shows intelligent use of models should
consider all of the model uncertainties and biases, include multiple
simulations, and ultimately produce, not a single design value, but a
range of predicted future design values.  This ensemble approach is
analogous to how a meteorologist determines a precipitation forecast.
The meteorologist looks at multiple meteorological models, considers
uncertainties and biases of each model, reviews circumstances the model
may not account for, determines if there are any other outside
extenuating factors, and finally ascertains a range of possible
outcomes.  This range is then delivered to the forecast audience.
Similarly, the MDE ensemble approach to weight of evidence modeling
provides a comprehensive evaluation of model performance for various
scales of time, area, height, and chemistry.  Based on the sensitivity
of the model under the evaluation schemes, a range of predicted 2009
8-hour ozone design values is forecasted for every monitoring site in
the Philadelphia non-attainment area.  The net result of applying
techniques of data analysis, observations, and modeling in the weight of
evidence is a favorable indication for successfully attaining the 8-hour
ozone NAAQS in 2009 for the area presently classified as the
Philadelphia non-attainment area.  This section provides a rigourous
scientific evaluation of the CMAQ performance, base case and future year
modeling, calculation of probable ranges, and alternative control
strategy modeling.

Evaluation of Model Abilities

An evaluation of model performance is performed using comparisons to
aircraft observations.  This analysis is important in understanding the
limitations of CMAQ and its strengths and weaknesses in simulating air
quality over the Mid-Atlantic in particular and the Ozone Transport
Region in general.  Appendix G-8 contains the full evaluation of CMAQ
against observations.

Evaluation using Observations

In an effort to assess the ability of the Community Multi-scale Air
Quality model (CMAQ) to replicate ozone patterns, particularly high
ozone events over the Ozone Transport Region (OTR), comparisons are
performed between surface and aircraft ozone measurements and CMAQ ozone
simulations using the 2002 base case B1 emissions inventory.  Overall,
CMAQ does an excellent job of capturing the mean distribution of surface
layer ozone during the ozone season. However, the success is somewhat
misleading.  EPA performance criteria may appear to be independent or
offer different information, but in reality, nearly all criteria are
strongly geared toward average performance at the surface.  This
analysis explores several other means of evaluating the CMAQ model by
examining its performance only on high ozone days, by separating
performance at rural, suburban, and urban sites, and by comparing CMAQ
to aloft ozone data from aircraft campaigns.  The mixed results of these
comparisons show that CMAQ has critical shortcomings (e.g., transport
appears to be underrepresented) that appear to be magnified during
periods when high ground level ozone concentrations are a concern.

Comparison with aircraft profiles from 136 Regional Atmospheric
Measurement Modeling and Prediction Program (RAMMPP) flights reveals
that CMAQ has an overall high bias of ~15% from the surface to ~500
meters above sea level (ASL) and a low bias aloft (600-2600 meters ASL)
of ~10%.  Agreement between CMAQ-calculated and aircraft-measured ozone
varies substantially from flight to flight.  CMAQ, in general,
replicates the spatial pattern of high ozone events but often does not
capture the full spatial extent or magnitude of the high ozone patterns.
 Mean CMAQ-calculated and measured 8-hour ozone values from 66 surface
ozone monitors in the Baltimore, Washington, D.C., and Philadelphia
non-attainment areas are highly correlated (correlation coefficient, R,
of 0.92) over the ozone season (May 15 – September 15) and well
correlated (R=0.81) when a subset of 38 high ozone days (i.e. days when
the peak daily 8-hour average ozone in Maryland exceeded 85 ppb) are
compared.  Biases between CMAQ-calculated and observed 8-hour ozone
mixing ratios are minimal (-1.6 ppb) when averaged over the entire ozone
season.  However, larger negative biases are seen during high ozone days
(-2.2 ppb at urban sites and -7.7 ppb at rural/suburban sites).

The high bias near the surface and low bias aloft is indicative of an
underestimation of ozone transport by CMAQ.  Aloft is where most
transport occurs; ground-level air does not move as readily.  On the
highest ozone days, CMAQ’s performance is not as good as on lower
ozone days.  This is a statistical reflection of CMAQ’s inability to
capture large-scale deviations from average or median conditions.  These
deviations occur on days with poor air quality.  CMAQ performs better at
urban sites than at suburban and rural areas.  This bias provides more
evidence that CMAQ is missing incoming ozone, possibly transport.  In
some instances, these rural/suburban areas are dominated by power-plant
emissions more than they are dominated by motor vehicle emissions. The
bias may also indicate that CMAQ’s relatively coarse vertical
resolution is unable to resolve the transport of point source (i.e.
power plant) emissions.  In particular, performance at upwind sites with
fewer nearby sources is poorer on the whole than it is at other sites
(see Appendix G-9).

None of these shortcomings are reflected in EPA’s traditional ozone
model performance measures.  However, these shortcomings make it
necessary to consider CMAQ output and other evidence when evaluating the
probability of success of State Implementation Plans (SIPs).  EPA model
performance criteria reveals that CMAQ does a good job of capturing
temporal fluctuations in 8-hour ozone over the ozone season.  However,
excellent performance in predicting domain-wide ozone averages does not
mean CMAQ will predict extreme ozone, ozone changes, or the dynamic
range of ozone concentrations at particular locations with similar
accuracy.   In this analysis, we show that CMAQ-calculated ozone
concentrations have systematic biases.  These biases must be considered
when using CMAQ for predicting ozone changes at particularly poor air
quality sites for the purpose of demonstrating future attainment status
with respect to the 8-hour ozone NAAQS.

Biases between CMAQ-calculated and measured 8-hour ozone concentrations
are minimal (1-2 ppbv) when averaged over the summer but larger (7-8
ppbv) on days when air quality is poor.   The inability of CMAQ to
capture the dynamic range of ozone concentrations is evidence that CMAQ
under responds to changes in meteorology and/or emissions.  Further
examples of the under responsive nature of CMAQ and the resulting
implications for SIP modeling are discussed in Appendix G-9.  Aircraft
observations show that CMAQ underestimates transport and has
compensating errors that overestimate the significance of local sources.
 This suggests that regional control programs should be more effective
than predicted by CMAQ and local programs somewhat less effective.
Since the bulk of the control programs are regional (e.g. fleet
turnover, heavy duty diesels, and the Clean Air Interstate Rule),
greater changes in surface ozone can be expected than those predicted by
CMAQ, especially given CMAQ’s lack of response to change (see Appendix
G-9).

CMAQ exhibits its best performance in urban areas (small bias), less
success in suburban areas (underestimates ozone, a larger negative
bias), and its worst performance in rural areas (underestimates ozone
more, larger negative bias).  Since ozone must pass through rural areas
to get to urban areas, CMAQ is likely underestimating transport.
CMAQ’s performance in capturing surface ozone is worst in the Ohio
River Valley and in central and southern Virginia, which are known to be
source regions for Maryland during high ozone episodes.  This relatively
poor performance adds uncertainty to estimates of transport into the
Mid-Atlantic region that are already likely biased low.

A detailed examination of Maryland ozone reveals that Maryland ozone
values improved significantly after the implementation of the NOx SIP
Call.  Ozone values were binned according to peak temperature to remove
most of the effects of meteorology from the analysis, revealing a
consistent 12% downward trend in ozone after the NOx SIP Call.

In regards to the demonstration of attainment, Maryland should be in
better, perhaps far better shape, than CMAQ predicts (see Appendix G-9).
 Demonstrated uncertainties and biases in CMAQ’s performance,
particularly with respect to extreme values and transport, imply that
CMAQ predicted future ozone concentrations are overestimated for the
Baltimore, Washington DC, and Philadelphia non-attainment areas.  Given
that CMAQ predicts a maximum 2009 8-hour ozone design value of 81 ppb at
the Fairhill monitor, this strongly suggests that Cecil County should be
firmly in attainment of the 8-hour ozone NAAQS in 2009.

Analysis of ozone trends before and after the NOx SIP Call reveals that
Maryland’s ozone concentrations improved significantly after the NOx
SIP Call.  This suggests that NOx controls, and especially power plant
controls are likely to be similarly effective in lowering ozone in the
future.

The ozone concentrations in Virginia and the Ohio River Valley (known
source regions for Maryland) are under-predicted.  In addition, CMAQ’s
performance is at its worst in upwind, rural areas, and at its best in
downwind urban areas with a small positive bias.  As a result, the
significance of regional controls including fleet turnover, heavy-duty