TABLE OF CONTENTS Page No.

15. ACTIVITY FACTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 15.1. ACTIVITY PATTERNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 15.1.1. Key Activity Pattern Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 15.1.2. Relevant Activity Pattern Studies . . . . . . . . . . . . . . . . . . . . . . . . . 7 15.2. OCCUPATIONAL MOBILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 15.2.1. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 15.2.2. Key Occupational Mobility Studies . . . . . . . . . . . . . . . . . . . . . . 11 15.3. POPULATION MOBILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 15.3.1. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 15.3.2. Key Population Mobility Studies . . . . . . . . . . . . . . . . . . . . . . . . 13 15.3.3. Relevant Population Mobility Studies . . . . . . . . . . . . . . . . . . . . 15 15.4. RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 15.4.1. Recommendations for Activity Patterns . . . . . . . . . . . . . . . . . . . 15 15.4.2. Recommendations: Occupational Mobility . . . . . . . . . . . . . . . . 17 15.4.3. Recommendations: Population Mobility . . . . . . . . . . . . . . . . . . . . . 17 15.4.4. Summary of Recommended Activity Factors . . . . . . . . . . . . . 18 15.5. REFERENCES FOR CHAPTER 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 1 15. ACTIVITY FACTORS In calculating exposure, a person's average daily populations in the U. S. The studies involve survey designs dose is determined from a combination of variables where time diaries were used to collect information on the including the pollutant concentration, exposure duration, time spent at various activities and locations for children, and frequency of exposure ( Sexton and Ryan, 1987). These adolescents, and adults, and to collect certain demographic variables can be dependent on human activity patterns and and socioeconomic data. Available studies on time activity time spent at each activity and/ or location. A person's total data are summarized in the following sections. It should be exposure can be predicted using indirect approaches such noted that other site limited studies, based on small sample as computerized mathematical models. This indirect sites, are available, but are not presented in this section. approach of predicting exposure also requires activity The studies presented in this section are ones believed to be patterns ( time use) data. Thus, individual or group the most appropriate for the purpose of the handbook. activities are important determinants of potential exposure Activity pattern studies are presented in Sections 15.1.1 and because toxic chemicals introduced into the environment 15.1.2. may not cause harm to an individual until an activity is performed subjecting the individual to contact with those contaminants. An individual's choice on how to spend time will vary according to their occupation, hobbies, culture, location, gender, age, and personal preferences. Educational level attained and socioeconomic status also influence chosen activities and their duration. The purpose of this section is to describe published time use studies that provide information on activities in which various individuals engage, length of time spent performing various activities, locations in which individuals spend time and length of time spent by individuals within those various microenvironments. According to Robinson and Thomas ( 1991), microenvironments refer to a combination of activities and locations that yield potential exposures. Information on time spent in specific occupations and residing in specific areas also is included in this section. This section summarizes data on how much time individuals spend doing various activities and in various microenvironments. These data cover a wide scope of activities and populations. The following table ( Table 15 1) should be used as a guide to locating the information relevant to activities and microenvironments of concern. Assessors can consider using these data to develop exposure duration estimates for specific exposure scenarios. Available studies are grouped as key or relevant studies. The classifications of these studies are based on the applicability of their data to exposure assessments. All tables that provide data from these studies are presented at the back of this chapter.

15.1. ACTIVITY PATTERNS about the child's previous day's activities. Children in first The purpose of this section is to describe published time use studies that provide information on time activity patterns of the national population and various sub

15.1.1. Key Activity Pattern Studies Timmer et al. ( 1985)  How Children Use Time  Timmer et al. ( 1985) conducted a study using the data obtained on children's time use from a 1981 1982 Panel study. This study was a follow up of households from a previous survey conducted in 1975 76. The 922 respondents in the 1981 82 study were those who had completed at least three out of four waves of interview in the 1975  1976 survey. Timmer et al. ( 1985) conducted the survey during February through December 1981, and households were contacted four times during a 3 month interval of the survey period. The first contact was a personal interview, followed by subsequent telephone interviews for most of the respondents. However, families with children were contacted personally and questionnaires were administered to a maximum of three children per household. The children surveyed were between the ages of 3 and 17 years and were interviewed twice. The questionnaires administered to children had two components: a time diary and a standardized interview. The time diary involved children reporting their activities beginning at 12.00 a. m. the previous night; the duration and location of each activity; the presence of another individual; and whether they were performing other activities at the same time. The standardized interview administered to the children was to gather information about their psychological, intellectual ( using reading comprehension tests), and emotional well being; their hopes and goals; their family environment; and their attitudes and beliefs. For preschool children, parents provided information through third grades completed the time Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 2 August 1997 diary with their parents assistance and, in addition, created by having younger children record their data should completed reading tests. Children in fourth grade and have been minimized. above provided their own diary information and participated in the interview. Parents were asked to assess their children's socioemotional and intellectual development. A survey form was sent to a teacher of each school age child to evaluate each child's socioemotional and intellectual development. The activity descriptor codes used in this study were developed by Juster et al. ( 1983). The activity codes and descriptors used for the adult time diaries in both surveys are presented in Appendix Table 15A 1. The mean time spent performing major activities on weekdays and weekends by age and sex, and type of day is presented in Table 15 2. On weekdays, children spend about 40 percent of their time sleeping, 20 percent in school, and 10 percent eating, washing, dressing, and performing other personal activities ( Timmer et al., 1985). The data in Table 15 2 indicates that girls spend more time than boys performing household work and personal care activities, and less time playing sports. Also, children spend most of their free time watching television. Table 15 3 presents the mean time children spend during weekdays and weekends performing major activities by five different age groups. Also, the significant effects of each variable ( i. e., age, sex) are shown in Table 15 3. Older children spend more time performing household and market work, studying and watching television, and less time eating, sleeping, and playing. Timmer et al. ( 1985) estimated that on the average, boys spend 19.4 hours a week watching television and girls spend 17.8 hours per week performing the same activity. A limitation associated with this study is that the data do not provide overall annual estimates of children's time use since the data were collected only during the time of the year when children attend school and not during school vacation. Another limitation is that a distribution pattern of children's time use was not provided. In addition, the survey was conducted in 1981 so there is a potential that activity patterns in children may have changed significantly from that period to the present. Therefore, application of these data for current exposure situations may bias exposure assessments results. An advantage of this survey is that diary recordings of activity patterns were kept and the data obtained were not based completely on recall. Another advantage is that because parents assisted younger children with keeping their diaries and with interviews, any bias that may have been James and Knuiman ( 1987)  An Application of Bayes Methodology to the Analysis of Diary Records from a Water Use Study  In 1987, James and Knuiman provided a distribution of the amount of time ( 1 20 minutes) spent showering by individuals in households located in Australia. The distribution presented in the study of James and Knuiman was based on diary records of 2,500 households. James and Knuiman ( 1987) reported that 50 additional households provided data for shower durations exceeding 20 minutes, but were excluded from their analysis because specific values over 20 minutes were not reported. Using the data of James and Knuiman, a cumulative frequency distribution was derived for the handbook, based on the 2,550 households and is presented in Table 15 3. Based on the results in Table 15 3, approximate showering times are 7 minutes for the median value, 13 minutes for the 90th percentile, 16 minutes for the 95th percentile, and > 20 minutes for the 99th percentile. The mean shower length is approximately 8 minutes using the shower durations of 1 to 20 minutes. A mean value could not be calculated using the data for the 50 households that reported showering time > 20 minutes. However, if a 30 minute showering time was assumed for the > 20 minutes duration, the mean value would be 8.5 minutes as compared to a mean of 8 minutes if these households are excluded. Therefore, including the 50 additional households would give a similar mean and the results at the upper end of the distribution would not be affected. A limitation of the study is that the data are from households in Australia and may not be representative of U. S. households. An advantage is that it presents cumulative distribution data. Robinson and Thomas ( 1991)  Time Spent in Activities, Locations, and Microenvironments: A California National Comparison  Robinson and Thomas ( 1991) reviewed and compared data from the 1987 88 California Air Resources Board ( CARB) time activity study and from a similar 1985 national study, American's Use of Time. Data from the national study were recorded similarly to the CARB code categories, in order to make data comparisons ( Robinson and Thomas, 1991). The CARB study involved residents who lived in the state of California. One adult 18 years or older was randomly sampled in each household and was asked to complete a diary with entries for the previous day's Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 3 activities and the location of each activity. Time use Californians spent more time on paid work, education and patterns for other individuals 12 years and older in the training, obtaining goods and services, and communication, households contacted were also included in the diaries. and less time on household work, child care, organizational Telephone interviews based on the random digit dialing activities, entertainment/ social activities, and recreation ( RDD) procedure were conducted for approximately 1,762 than the national population. The male and female respondents in the CARB survey. These interviews were population closely followed the same trends as the general distributed across all days of the week and across different population. Table 15 6 shows the mean time spent at 3 months of the year ( between October 1987 August 1988). major locations for the CARB and national study grouped In the 1985 National study, single day diaries were by total sample and gender, ages 18 64 years ( time use data collected from over 5,000 respondents across the U. S., 12 for the 44 detailed microenvironments are presented in years of age and older. The study was conducted during Appendix Table 15A 3). Respondents spent most of their January through December 1985. Three modes of time time at home, 892 minutes/ day for the CARB and 954 diary collection were employed for this survey: mailback, minutes/ day for the national study. Californians spent more telephone interview, and personal interview. Data obtained of their time away from home and traveling compared to the from the personal interviews were not used in this study national population. ( Robinson and Thomas, 1991). The sample population for In addition, Robinson and Thomas ( 1991) defined a the mail back and telephone interview was selected based set of 16 microenvironments based on the activity and on a RDD method. The RDD was designed to represent all location codes employed in both studies. The analysis telephone households in the contiguous United States included data for adolescents ( 12 17 years) and adults ( 65 ( Robinson and Thomas, 1991). In addition to estimates of years and older) in both the CARB study and the mail back time spent at various activities and locations, the survey portion of the 1985 national study ( Robinson and Thomas, design provided information on the employment status, age, 1991). The mean duration of time spent in locations for education, race, and gender for each member of the total sample population, 12 years and older, across three respondent's household. The mail back procedure was types of locations is presented in Table 15 7 for both based on a " tomorrow" approach, and the telephone studies. Respondents spent most of their time indoors, interview was based on recall. In the " tomorrow" approach, 1255 and 1279 minutes/ day for the CARB and national respondents know, and agree ahead of time, that they will be study, respectively. keeping a diary ( Robinson and Thomas, 1991). Table 15 8 presents the mean duration of time and Data comparisons by Robinson and Thomas ( 1991) standard mean error for the 16 microenvironments grouped were based on 10 major activity categories ( 100 sub by total sample population and gender. Also included is the category codes) and 3 major locations ( 44 sub location mean time spent for respondents (" Doers") who reported codes) employed in both the CARB and the 1985 national participating in each activity. Table 15 8 shows that in both study. In order to make data comparisons, Robinson and studies men spend more time in work locations, Thomas ( 1991) excluded responses from individuals of automobiles and other vehicles, autoplaces ( garages), and ages 65 years and older and 18 years or younger in both physical outdoor activities, outdoor sites. In contrast, surveys. In addition, only mail back responses were women spend more time cooking, engaging in other kitchen analyzed for the 1985 national study. The data were then activities, performing other chores, and shopping. The weighted to project both the California and national same trends also occur on a per participant basis. population in terms of days of the week, region, numbers of Table 15 9 shows the mean time spent in various respondents per household, and 3 monthly seasons of the microenvironments grouped by type of the day ( weekday or year ( Robinson and Thomas, 1991). weekend) in both studies. Generally, respondents spent Table 15 5 shows the mean time spent in the 10 most of their time during the weekends in restaurants/ bars major activities by gender and for all respondents between ( CARB study), motor vehicles, outdoor activities, socialthe ages of 18 64 years ( time use data for the individual cultural settings, leisure/ communication activities, and activities are presented in Appendix Table 15A 2). In both sleeping. Microenvironmental differences by age are studies respondents spent most of their time ( 642 mins/ day) presented in Table 15 10. Respondents in the age groups on personal needs and care ( i. e., sleep). 18 24 years and 25 44 years spent most of their time in Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 4 August 1997 restaurants/ bars and traveling. The oldest age group, 65 The data obtained from the survey interviews years and older, spent most of their time in the kitchen resulted in ten major activity categories, 113 detailed ( cooking and other kitchen related activities) and in activity codes, 6 major categories of locations, and 63 communication activities. detailed location codes. The average time respondents spent Limitations associated with the Robinson and during the 10 activity categories for all children are Thomas ( 1991) study are that the CARB survey was based presented in Table 15 11. Also included in this table are on recall and the survey was performed in California only. the detailed activity, including its code, with the highest Therefore, if applied to other populations, the data set may mean duration of time; the percentage of respondents who be biased. Another limitation is that time distribution reported participating in any activity ( percent doing); and patterns ( statistical analysis) were not provided for both the mean, median, and maximum time duration for " doers." studies. Also, the data are based on short term studies. An The dominant activity category, personal care ( night sleep advantage of this study is that the 1985 national study being the highest contributor), had the highest time represents the general U. S. population. Also, the 1985 expenditure of 794 mins/ day ( 13.2 hours/ day). All national study provides time estimates by activities, respondents reported sleeping at night, resulting in a mean locations, and microenvironments grouped by age, gender, daily time per participant of 794 mins/ day spent sleeping. and type of day. Another advantage is that the data were The activity category " don't know" had a duration of about compared and that, overall, both data sets showed similar 2 mins/ day and only 4 percent of the respondents reported patterns of activity ( Robinson and Thomas, 1991). missing activity time. Wiley et al. ( 1991)  Study of Children's Activity Patterns  The California children's activity pattern survey design provided time estimates of children ( under 12 years old) in various activities and locations ( microenvironments) on a typical day ( Wiley et al., 1991). The sample population, which consisted of 1,200 respondents ( including children under 12 years of age and adult informants residing in the child's household), was selected using Waksberg RDD methods from English speaking households. One child was selected from each household. If the selected child was 8 years old or less, the adult in the same household who spent the most time with the child responded. However, if the selected child was between 9 and 11 years old, that child responded. The population was also stratified to provide representative estimates for major regions of the state. The survey questionnaire included a time diary which provided information on the children's activity and location patterns based on a 24 hour recall period. In addition, the survey questionnaire included questions about potential exposure to sources of indoor air pollution ( i. e., presence of smokers) on the diary day and the socio demographic characteristics ( i. e., age, gender, marital status of adult) of children and adult respondents. The questionnaires and the time diaries were administered via a computer assisted telephone interviewing ( CATI) technology ( Wiley et al., 1991). The telephone interviews were conducted during April 1989 to February 1990 over four seasons: Spring ( April June 1989), Summer ( July September 1989), Fall ( October December 1989), and Winter ( January February 1990). Table 15 12 presents the mean time spent in the 10 activity categories by age and gender. Differences in activity patterns for boys and girls tended to be small. Table 15 13 presents the mean time spent in the 10 activity categories grouped by seasons and California regions. There were seasonal differences for 5 activity categories: personal care, educational activities, social/ entertainment, recreation, and communication/ passive leisure. Time expenditure differences in various regions of the State were minimal for childcare, work related activities, shopping, personal care, education, social life, and recreation. Table 15 14 presents the distribution of time across six location categories. The participation rates ( percent) of respondents, the mean, median, and maximum time for " doers." The detailed location with the highest average time expenditure are also shown. The largest amount of time spent was at home ( 1,078 minutes/ day); 99 percent of respondents spent time at home ( 1,086 minutes/ participant/ day). Tables 15 15 and 15 16 show the average time spent in the six locations grouped by age and gender, and season and region, respectively. There are age differences in time expenditure in educational settings for boys and girls ( Table 15 15). There are no differences in time expenditure at the six locations by regions, and time spent in school decreased in the summer months compared to other seasons ( Table 15 16). Table 15 17 shows the average potential exposure time children spent in proximity to tobacco smoke, gasoline fumes, and gas oven fumes grouped by age and gender. The sampled children spent more time closer to tobacco smoke ( 77 Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 5 mins/ day) than gasoline fumes ( 2 mins/ day) and gas oven Computer Assisted Telephone Interviewing ( CATI). The fumes ( 11 mins/ day). response rate was 63 percent, overall. If the chosen A limitation of this study is that the sampling respondent was a child too young to interview, an adult in population was restricted to only English speaking the household gave a proxy interview. Each participant was households; therefore, the data obtained does not represent asked to recount their entire daily routine from midnight to the diverse population group present in California. Another midnight immediately previous to the day that they were limitation is that time use values obtained from this survey interviewed. The survey collected information on duration were based on short term recall ( 24 hr) data; therefore, the and frequency of selected activities and of the time spent in data set obtained may be biased. Other limitations are: the selected microenvironments. In addition, demographic survey was conducted in California and is not representative information was collected for each respondent to allow for of the national population, and the significance of the statistical summaries to be generated according to specific observed differences in the data obtained ( i. e., gender, age, subgroups of the U. S. population ( i. e., by gender, age, race, seasons, and regions) were not tested statistically. An employment status, census region, season, etc.). The advantage of this study is that time expenditure in various participants' responses were weighted according to activities and locations were presented for children grouped geographic, socioeconomic, time/ season, and other by age, gender, and seasons. Also, potential exposures of demographic factors to ensure that results were respondents to pollutants were explored in the survey. representative of the U. S. population. The weighted sample Another advantage is the use of the CATI program in matches the 1990 U. S. census population for each gender, obtaining time diaries, which allows automatic coding of age group, census region, and the day of week and seasonal activities and locations onto a computer tape, and allows responses are equally distributed. Saturdays and Sundays activities forgotten by respondents to be inserted into its were over sampled to ensure an adequate weekend sample. appropriate position during interviewing ( Wiley et al., The data presented are a compilation of 24 hour 1991). diary locations, activities, and follow up exposure questions U. S. EPA ( 1992)  Dermal Exposure Assessment: Principles and Applications  U. S. EPA ( 1992) addressed the variables of exposure time, frequency, and duration needed to calculate dermal exposure as related to activity. The reader is referred to the document for a detailed discussion of these variables in relation to soil and water related activities. The suggested values that can be used for dermal exposure are presented in Table 15 18. Limitations of this study are that the values are based on small data sets and a limited number of studies. An advantage is that it presents default values for frequency and duration for use in exposure assessments when specific data are not available. Tsang and Klepeis ( 1996)  National Human Activity Pattern Survey ( NHAPS)  The National Human Activity Pattern Survey was conducted by the U. S. EPA ( Tsang and Klepeis, 1996). It is the largest and most current human activity pattern survey available ( Tsang and Klepeis, 1996). Data for 9,386 respondents in the 48 contiguous United States were collected via minute byminute 24 hour diaries between October 1992 and September 1994. Detailed data were collected for a maximum of 82 different possible locations, and a maximum of 91 different activities. Participants were selected using a Random Digit Dial ( RDD) method and based on exposure related events ( personal, exposure, household characteristics, medical background) ( Tsang and Klepeis, 1996). Data presented are reported in the form of means, percentages of time spent, and percentages of respondent occurrences. The diary data are useful for obtaining national representative distributions of time spent in a large variety of activities and locations in a single day ( Tsang and Klepeis, 1996). According to Tsang and Klepeis ( 1996), the 24 hour diaries in the NHAPS are useful in probabilistic modeling ( Monte Carlo) that provides frequency distributions of exposure. Overall survey results indicate that for time spent in microenvironments, the largest overall percentage of time was spent in residential indoors ( 67 percent), followed by time spent outdoors ( 8 percent), and then time spent in vehicles ( 5 percent) ( Tsang and Klepeis, 1996). Tables 15 19 through 15 146 provide data from the NHAPS study. NHAPS data on the time spent in selected activities are presented in Tables 15 19 through 15 92. NHAPS data on the time spent in selected microenvironments are presented in Tables 15 93 to 15 139 and of these tables, Tables 15 66 through 15 139 present 24 hour cumulative statistics ( mean, minimum, maximuim, and percentiles) data for time spent in various activities and in various microenvironments. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 6 August 1997 C Tables 15 19 through 15 32 provide working in circumstances where one comes in information on the frequency and duration of contact with soil such as in a garden. taking baths, frequency of taking showers, and on the amount of time spent in the shower or C Tables 15 65 through 15 67 provide bathroom after completion of the activity. information on the frequency of swimming in a C Table 15 33 provides the frequency for washing time spent swimming during a 1 month period. the hands in a day.

C Tables 15 34 through 15 36 present information on time spent by persons working with or being near foods while being grilled or barbecued; working with or near open flames; and working or being near excessive dust in the air.

C Tables 15 37 through 15 39 provide data for the number of times a vehicle was started in a garage or carport and if started with the door closed; and for time spent at a gas station or repair shop.

C Tables 15 40 through 15 42 present information on the number of times windows and doors were opened and the number of minutes they were left open at home while the respondent was at home.

C Tables 15 43 through 15 47 provide data for time spent in heavy traffic either running, walking, standing, or in a vehicle; and for time spent in indoor and outdoor parking lots and garages.

C Tables 15 48 through 15 50 present information for time spent working for pay; working at different times of day; and for the amount of that time was spent working outdoors.

C Tables 15 51 through 15 56 provide information for number of times of performing household tasks in a day such as vacuuming, and washing dishes and clothes in a residence.

C Tables 15 57 through 15 64 present data for number of times per day and the duration for playing in sand, gravel, and dirt; and for fresh water swimming pool and the amount of C Tables 15 68 through 15 87 present statistics for time spent in various major categories. They are as follows: Paid Work ( main job); Household Work ( food preparation and cleanup, cleaning house, clothes care); Child Care ( indoor and outdoor playing); Obtaining Goods and Services ( car repair); Personal Needs and Care ( sleeping/ napping); Free Time and Education ( school); and Recreation ( active sports, exercise, outdoor recreation).

C Tables 15 88 through 15 94 provide statistics for time spent in various activities that are the results of regrouping/ combining activities described in Tables 15 68 through 15 87. Because the occurrences in some major categories were too small to conduct analyses, these categories were regrouped into broader categories so that new categories could be developed with a larger number of occurrences ( Tsang and Klepeis, 1996). This regrouping was performed to create a better data set for estimating exposure activities from the available data ( Tsang and Klepeis, 1996).

C Tables 15 95 through 15 103 provide cumulative statistics for time spent in various indoor microenvironments such as repair shops/ gas stations; bar/ night club/ bowling alley; and at school.

C Tables 15 104 through 15 112 present statistical data for time spent in various outdoor locations. These tables include data for locations such as schoolgrounds/ playground; parking lots; construction sites; parks and golf courses; and farms. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 7 C Tables 15 113 through 15 120 present statistics for time spent in various locations in the home. Data are presented for the number of minutes spent in the kitchen, bathroom, bedroom, garage, basement, utility room or laundry room; in the outdoor pool or spa; and in the yard or other areas outside the house.

C Tables 15 121 through 15 130 provide data on time spent traveling and for traveling in various types of vehicles; and for time spent walking.

C Tables 15 131 through 15 140 provide statistics for total time spent indoors at home ( categories regrouped/ combined based on various data described in Tables 15 95 through 15 130), including all rooms; outdoors at home; traveling inside a vehicle; outdoors near a vehicle; outdoors other than near a residence; in an office or factory; in malls and other stores; in various public buildings; in bars, restaurants, etc.; and outdoor locations such as auto repair shops and laundromats.

C Table 15 141 provides the number of minutes spent in an activity or microenvironment where a smoker was present.

C Tables 15 142 and 15 143 present data for time spent smoking in a day.

C Tables 15 144 through 15 148 provide information for time spent smoking selected tobacco products such as cigars, cigarettes, and pipe tobacco.

Advantages of the NHAPS dataset are that it is representative of the U. S. population and it has been adjusted to be balanced geographically, seasonally, and for day/ time. Also, it is representative of all ages, gender, and is race specific. A disadvantage of the study is that means cannot be calculated for time spent over 60, 120, and 181 minutes in selected activities. Therefore, actual time spent at the high end of the distribution for these activities cannot be captured. 15.1.2. Relevant Activity Pattern Studies Robinson  Changes in Americans' Use of Time: 1965 1975 ( 1977)  Robinson ( 1977) compared time use data obtained from two national surveys that were conducted in 1965 1966 and in 1975. Each survey used the time diary method to collect data. The 1965 66 survey excluded people in the following categories: ( a) Non Standard Metropolitan Statistical Area ( non SMSA) ( designation of Census Bureau areas having no city with more than 50,000 population); ( b) households where no adult members were in the labor force for at least 10 hours per week; ( c) age 65 and over; and ( d) farm related occupations ( Robinson, 1977). The 1,244 respondents in the 1965 66 study included either employed men and women or housewives ( Robinson, 1977). The survey was conducted between November December 1965 and March April 1966. Respondents recorded their daily activities in time diaries by using the " tomorrow" approach. In this approach, diaries were kept on the day following the interviewer's initial contact. The interviewer then made a second call to the respondent to determine if the information in diaries were correct and to obtain additional data. Only one person per household was interviewed. The survey was designed to obtain information on time spent with family members, time spent at various locations during activities, and performing primary and secondary activities. A similar study was conducted in 1975 from October through December. Unlike the 1965 1966 survey, the 1975 survey included rural areas, farmers, the unemployed, students, and retirees. Time diary data were collected using the " yesterday" approach. In this approach, interviewers made only one contact with respondents ( greater than 1500) and the diaries were filled out based on a 24 hour recall ( Robinson, 1977). Time diary data were also collected from the respondents' spouses. In both surveys, the various activities were coded into 96 categories, and then were combined into five major categories. Free time activities were grouped into 5 subcategories ( Appendix Table 15A 2). In order to compare data obtained from both surveys, Robinson ( 1977) excluded the same population groups in the 1975 survey that were excluded in the 1965 66 survey ( i. e., farmers, rural residents). Results obtained from the surveys were presented by gender, age, marital and employment status, race, and education. Robinson ( 1977) reported the data collected in hours/ week; however, the method for converting daily Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 8 August 1997 activities to hours/ week were not presented. Table 15 149 shows the differences in time use by gender, employment, and marital status for five major activity categories and five subcategories for 1965 and 1975. Time spent on work related activities ( i. e., work for pay and family care) was lower in 1975 than in 1965 for employed men and women. Table 15 149 also shows that there was an overall increase in free time activities for all the six groups. The difference in time use in 1965 and 1975 are presented by age, education, and race in Tables 15 150, 15 151, and 15 152, respectively. These tables include data for students and certain employed respondents that were excluded in Table 15 148 ( Robinson, 1977). In 1975, the eldest group ( ages 56 65 years) showed a decline in paid work, and an increase in family care, personal care and sleep ( Table 15 150). Education level comparisons across the ten year interval indicated that the less educated had a decrease in paid work and an increase in sleep and personal care; the most educated had an increase in work time and a decrease in other leisure ( Table 15 151). For racial comparisons, Blacks spent less time at paid work than Whites across the ten year interval ( Table 15 152). Table 15 152 also shows that Blacks spent more time than Whites at free time activities in 1975. A limitation of the study survey design is that time use data were gathered as social indicators. Therefore, the activity categories presented may not be relevant in exposure assessments. Another limitation is that statistical analysis of the data set was not provided. Additional limitations are that the time use data are old and the data may not reflect recent changes in time use. The 1965 and 1975 data sets excluded certain population groups and, therefore, may not be entirely representative of the U. S. population. Another limitation is that these are short term studies and may not necessarily represent long term activity patterns. An advantage of this study is that time use data were presented by age, gender, race, education level, and employment and marital status. Another advantage is that earlier investigations on the study method ( 24 hr recall) employed in the 1965 study revealed no systematic biases in reported activities ( Robinson, 1977). Robinson ( 1977) also noted that the time diary method provides a " zero sum" measure ( i. e., since there are only 24 daily hours or 168 weekly hours, if time on one activity increases then time on another activity must decrease). Juster et al. ( 1983)  1975 1981 Time Use Longitudinal Panel Study  The Time Allocation longitudinal study of the U. S. population began as part of a multinational project with the first survey conducted in 1965 66. A second national time use survey was conducted in 1975 1976 and another in 1981 ( Juster et al. 1983). Juster et al. ( 1983) provided study descriptions of the second and third surveys. The surveys included a probability sample of the adult population ( 18 years and older) and children between the ages of 3 and 17 years in the United States. In both surveys, time use was measured from 24 hour recall diaries administered to respondents and their spouses. The 1975 1976 survey involved four waves of interview: wave 1, October November 1975; wave 2, February 1976; wave 3, May June 1976; wave 4, September 1976. The first wave was a personal interview and the other three waves were telephone interviews. The 1975 1976 survey sample consisted of 2,300 individuals, and of that sample, 1,519 respondents. Four recall diaries ( one from each wave of interviews) were obtained from 947 respondents, with data on time use measures for two weekdays, one Saturday and one Sunday. The survey was designed to gather information for: employment status; earnings and other income; " consumption benefits for activities of respondents and their spouses;" health, friendships and associations of the respondents; stock technology available to the household, house repair, and maintenance activities of the family; division of labor in household work and related attitudes; physical characteristics of the respondents housing structure, net worth and housing values; job characteristics; and characteristics of mass media usage on a typical day ( Juster et al., 1983). The 1981 survey was a follow up of respondents and spouses who had completed at least three waves of interview in the 1975 1976 survey. For the 1981 survey, 920 individuals were eligible. The survey design was similar to the 1975 1976 survey, however in this survey, the adult population was 25 years and older and consisted of 620 respondents. Four waves of interviews were conducted between February  March 1981 ( wave 1), May  June 1981 ( wave 2), September 1981 ( wave 3), and November  December ( wave 4). The 1981 survey included the respondents' children between the ages of 3 and 17 years. The survey design for children provided information on time use measures from two time diary reports: one school day and one non school day. In addition, information for academic achievement measures, Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 9 school and family life measures, and ratings from the through the fall of 1976 for the 1975 1976 Time Allocation children's teachers were gathered during the survey. Study. The sampling periods included two weekdays, one Juster et al. ( 1983) did not report the time use data Saturday and one Sunday. The 1975 1976 Time Allocation obtained for the 1975 1976 survey or the 1981 survey. Study provided information on the amount of time spent These data are stored in four tape files and can be obtained performing primary activities. The information gathered from the Inter university Consortium for Political and Social were responses to the survey question " What were you Research ( ICPSR) in Michigan. The response rate for the doing?" The survey also provided information on secondary first wave of interview ( 1975 76 survey) based on the activities ( i. e., respondents performing more than one original sample population was 66 percent, and response activity at the same time). Hill ( 1985) analyzed time rates for the subsequent waves ranged from 42 percent estimates for 10 broad categories of activities based on data ( wave 4) to 50 percent ( wave 2). In the 1981 survey, the collected from 87 activities. These estimates included response rate based on eligible respondents was 67 percent seasonal variation in time use patterns and comparisons of for the first interview, and ranged from 54 percent ( wave 4) time use patterns for different days of the week. The 10 to 60 percent ( wave 2) in the subsequent interviews ( Juster major categories and ranges of activity codes are listed in et al., 1983). The 1975 1976 survey included 87 activities. Appendix Table 15A 4. Hill ( 1985) collected data on time In the 1981 survey, these 87 activities were broken down use for the major activity patterns in four different age into smaller components, resulting in 223 activities ( Juster groups ( 18 24, 25 44, 45 64, and 65 years and older). et al., 1983). The activity codes and descriptors used for However, the time use data were summarized in graphs the adult time diaries in both surveys are presented in rather than in tables. Appendix Table 15A 3. Analysis of the 1975 76 survey data revealed very A limitation of this study is that the surveys were not small regional differences in time use among the broad designed for exposure assessment purposes. Therefore, the activity patterns ( Hill, 1985). The weighted mean hours per time use data set may be biased. Another limitation is that week spent performing the 10 major activity categories time use data collected were based on a 24 hour diary presented by region are shown in Table 15 153. In all recall. This may somewhat bias the data set obtained from regions, adults spent more time on personal care ( included this survey. An advantage associated with this survey is that night sleep). Adults in the North Central region of the it provides a database of information on various human country spent more time on market work activities than activities. This information can be used to assess various adults in other regions of the country. Adults in the South exposure pathways and scenarios associated with these spent more time on leisure activities ( passive and active activities. Also, some of the data from these surveys were combined) than adults elsewhere ( Table 15 153). Table used in the studies conducted by Timmer et al. ( 1985) and 15 154 presents the time spent per day, by the day of the Hill ( 1985). In addition, the activity descriptor codes week for the 10 major activity categories. Time spent on developed in these studies were used by Timmer et al the 87 activities ( components of the 10 major categories) ( 1985), Hill ( 1985), and Robinson and Thomas ( 1991). are presented in Appendix Table 15A 5. Adult time use These studies are presented in Sections 15.1.1 and 15.1.2. was dominated in descending order by personal care Another advantage of this survey is that the data are based ( including sleep), market work, passive leisure, and house on a national survey and conducted over a one year period, work. Collectively, these activities represent about 80 resulting in a seasonally balanced survey and one percent of available time ( Hill, 1985). representative of the U. S. population. According to Hill ( 1985), sleep was the single most Hill ( 1985)  Patterns of Time Use  Hill ( 1985) investigated the total amount of time American adults spend in one year performing various activities and the variation in time use across three different dimensions: demographic characteristics, geographical location, and seasonal characteristics. In this study, time estimates were based on data collected from time diaries in four waves ( 1 per season) of a survey conducted in the fall of 1975 dominant activity averaging about 56.3 hours per week. Television watching ( passive leisure) averaged about 21.8 hours per week, and housework activities averaged about 14.7 hours per week. Weekdays were predominantly market work oriented. Weekends ( Saturday and Sunday) were predominantly devoted to household tasks (" sleeping in," socializing, and active leisure) ( Hill, 1985). Table 15 155 presents the mean time spent performing these 10 groups of activities during each wave of interview ( fall, winter, spring, and summer). Adjustments Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 10 August 1997 were made to the data to assure equal distributions of or at home in the presence of a parent or an adult careweekdays Saturdays, and Sundays ( Hill, 1985). The data provider. In the course of the interview, children were indicates that the time periods adults spent performing asked to identify locations of activity areas, social areas ( i. e., market work, child care, shopping, organizational activities, places they went with friends), favorite areas, and locations and active leisure were fairly constant throughout the year of forts or clubhouses. Aerial photographs were used to ( Hill, 1985). The mean hours spent per week in performing mark these areas. the 10 major activity patterns are presented by gender in The second survey involved only preschool children. Table 15 156 ( time use patterns for all 87 activities are Parents completed questionnaires which provided presented in Appendix Table 15A 6). Table 15 156 information on the amount of time their children spent indicates that time use patterns determined by data collected outdoors, outdoor play locations, favorite places, digging for the mid 1970' s survey show gender differences. Men areas, use of park or playgrounds, and swimming or wading spent more time on activities related to labor market work locations. This survey was conducted between June July and education, and women spent more time on household 1989. One thousand ( 1,000) parents were sampled, but work activities. only 211 questionnaires were usable out of 886 A limitation associated with this study is that the time questionnaires received resulting in a response rate for the data were obtained from an old survey conducted in the preschool's survey of about 24 percent. The sample mid 1970s. Because of fairly rapid changes in American population consisted of children 1 month and up to society, applying these data to current exposure assessments preschool age. Of this population, 53 percent were Anglos, may result in some biases. Another limitation is that time 18 percent Hispanics, 2 percent Blacks, and 3 percent use data were not presented for children. An advantage of Asians. this study is that time diaries were kept and data were not The survey design considered the kinds of activities based on recall. The former approach may result in a more children engaged in, but not the amount of time children accurate data set. Another advantage of this study is that the spent in each activity. Therefore, Sell ( 1989) presented the survey is seasonally balanced since it was conducted data obtained from the survey in terms of percent of throughout the year and the data are from a large survey respondents who engaged in specific activities or locations. sample. A summary of percent responses of the preschool and Sell ( 1989)  The Use of Children's Activity Patterns in the Development of a Strategy for Soil Sampling in West Central Phoenix  In a report prepared for the Arizona Department of Environmental Quality, Sell ( 1989) investigated the activity patterns of preschool and school age children in the west central portion of Phoenix known as Maryvale. The survey was conducted in two parts: ( 1) most of the school age children were interviewed personally from May through June, 1989 in three schools; and ( 2) survey questionnaires were mailed to parents of preschool children. In the first survey, 15 percent of the total school population ( 2,008) was sampled with 111 children in grades K 6 participating ( response rate of 37 percent). The surveyed population was 53.2 percent male and 46.8 percent female. Of this population, 41 percent were Hispanics, 49.5 percent Anglos, 7.2 percent Blacks, and 1.7 percent Asians. The children interviewed were between the ages of 5 and 13 years. Within each school, the children in grades K 6 were stratified into two groups, primary ( grades K 3) and intermediate ( grades 4 6), and children were selected randomly from each group. Children in grades K 2 were either interviewed in school school age children's activities at various locations in the Maryvale study areas are presented in Table 15 157. Also included in this table is a ranking of children's play locations based on other existing research works. Based on the survey data, Sell ( 1989) reported that the median time preschool children spent outdoors on weekdays was 1 2 hours, and on weekends the median time spent outdoors was 2 5 hours. Most of these children played outside in their own yards, and some played in other people's yards or parks and playgrounds ( Sell, 1989). Limitations associated with this study are that the survey design did not report the time spent in various activities or locations and the response rates obtained from the surveys were low and, therefore, may result in biased data. In addition, because the survey was conducted in Arizona, the surveyed population does not represent the children's population on a national basis. Advantages of this study are that it provides data on various activities children engage in and locations of these activities, and provides for time spent outdoors. This information is useful in determining exposure pathways to toxic pollutants for children. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 11 Tarshis ( 1981)  The Average American Book  Tarshis ( 1981) compiled a book addressing the habits, tastes, lifestyles, and attitudes of the American people in which he reported data on time spent in personal grooming. The data presented are gathered from small surveys, the Newspaper Advertising Bureau, and magazines. Tarshis reported frequency and percentage data by gender and age 15.2. OCCUPATIONAL MOBILITY for grooming activities such as showering and bathing as 15.2.1. Background follows:

° 90 percent take some sort of a bath in an average 24 hour period; ° 5 percent average more than 1 shower or bath a day; ° 75 percent of men shower, 25 percent take baths; ° 50 percent of women take showers, 50 percent take baths; ° 65 percent of teenage girls 16 19 shower daily; ° 55 percent of teenage girls take at least one bath a week; ° 50 percent of women use an additive in their bath every time they bathe; ° People are more likely to shower than bathe if they are young and have higher income; and ° Showering is more popular than bathing in large 15.2.2. Key Occupational Mobility Studies cities. Carey ( 1988)  Occupational Tenure in 1987:

Limitations of this study are that the data are compiled from other sources, and that the data are old; it is possible that these data may not reflect the current trends of the general population. An advantage of the study is that it presents frequency data that are useful in exposure assessment, especially concerning volatilization of chemicals from water. AIHC ( 1994)  Exposure Factors Sourcebook  The was obtained from supplemental data to the January 1987 activity factors data presented in the Sourcebook are similar Current Population Study, a U. S. Bureau of the Census to that in this handbook. The AIHC Sourcebook uses publication. Carey ( 1988) did not present information on tenure data from the Bureau of Labor Statistics ( 1987), the survey design. while this handbook uses more recent data ( Carey, 1988) The median occupational tenure by age and gender, and provides general and specific recommendations for ethnicity, and employment status are presented in Tables various age groups. Distributions were derived using data 15 158, 15 159, and 15 160, respectively. The median presented in U. S. EPA ( 1989) version of this handbook, the occupational tenure of the working population ( 109.1 Bureau of Labor Statistics ( 1987), and various other million people) 16 years of age and older in January of references. Distribution data and/ or recommendations are 1987, was 6.6 years ( Table 15 158). Table 15 158 also presented for time in one residence, residential occupancy, shows that median occupational tenure increased from 1.9 time spent indoors/ outdoors, hours at home/ away from years for workers 16 24 years old to 21.9 years for workers home for adults and children, hours at work for adults, 70 years and older. The median occupational tenure for working tenure, and shower duration. For each distribution, men 16 years and older was higher ( 7.9 years) than for the @ Risk formula is provided for women of the same age group ( 5.4 years). Table direct use in the @ Risk software ( Palisade, 1992). The Sourcebook has been classified as a relevant rather than a key study because it is not the primary source for the data used to make recommendations. It is a relevant source of alterative information.

The amount of time spent in different types of occupations may affect the duration and/ or magnitude of exposures to contaminants specific to those occupations. For example, an individual who spends an entire lifetime as a farmer may experience a longer duration of exposure to certain contaminants, especially pesticides, than individuals who have indoor occupations. Also, individual exposures to specific chemicals in the work place may be significantly reduced when individuals change jobs. Work place exposures among women may be of shorter duration than among men because women's careers may be interrupted by home and family responsibilities. The key studies presented in the following section provide occupational tenure for workers grouped by age, race, gender, and employment status.

Many Workers Have Remained in Their Fields  Carey ( 1988) presented median occupational and employer tenure for different age groups, gender, earnings, ethnicity, and educational attainment. Occupational tenure was defined as " the cumulative number of years a person worked in his or her current occupation, regardless of number of employers, interruptions in employment, or time spent in other occupations" ( Carey, 1988). The information presented Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 12 August 1997 15 159 indicates that whites had longer occupational tenure mobility was defined as " the number of workers who change ( 6.7 years) than blacks ( 5.8 years), and Hispanics ( 4.5 from one occupation to another" ( Carey, 1990). years). Full time workers had more occupational tenure Occupational mobility was measured by asking individuals than part time workers 7.2 years and 3.1 years, respectively who were employed in both January 1986 and January 1987 ( Table 15 160). if they were doing the same kind of work in each of these Table 15 161 presents the median occupational months ( Carey, 1990). Carey ( 1990) further analyzed the tenure among major occupational groups. The median occupational mobility data and obtained information on tenure ranged from 4.1 years for service workers to 10.4 entry and exit rates for occupations. These rates were years for people employed in farming, forestry, and fishing. defined as " the percentage of persons employed in an In addition, median occupational tenure among detailed occupation who had voluntarily entered it from another occupations ranged from 24.8 years for barbers to 1.5 years occupation" and an exit rate was defined as " the percentage for food counter and fountain workers ( Appendix Table of persons employed in an occupation who had voluntarily 15A 7). left for a new occupation" ( Carey, 1990). The strength of an individual's attachment to a Table 15 162 shows the voluntary occupational specific occupation has been attributed to the individual's mobility rates in January 1987 for workers 16 years and investment in education ( Carey, 1988). Carey ( 1988) older. For all workers, the overall voluntary occupational reported the median occupational tenure for the surveyed mobility rate was 5.3 percent. These data also show that working population by age and educational level. Workers younger workers left occupations at a higher rate than older with 5 or more years of college had the highest median workers. Carey ( 1990) reported that 10 million of the occupational tenure of 10.1 years. Workers that were 65 100.1 million individuals employed in January 1986 and in years and older with 5 or more years of college had the January 1987 had changed occupations during that period, highest occupational tenure level of 33.8 years. The median resulting in an overall mobility rate of 9.9 percent. occupational tenure was 10.6 years for self employed Executive, administrative, and managerial occupations had workers and 6.2 years for wage and salary workers ( Carey, the highest entry rate of 5.3 percent, followed by 1988). administrative support ( including clerical) at 4.9 percent. A limitation associated with this study is that the Sales had the highest exit rate of 5.3 percent and service survey design employed in the data collection was not had the second highest exit rate of 4.8 percent ( Carey, presented. Therefore, the validity and accuracy of the data 1990). In January 1987, the median employer tenure for all set cannot be determined. Another limitation is that only workers was 4.2 years. The median employee tenure was median values were reported in the study. An advantage of 12.4 years for those workers that were 65 years of age and this study is that occupational tenure ( years spent in a older ( Carey, 1990). specific occupation) was obtained for various age groups by Because the study was conducted by Carey ( 1990) in gender, ethnicity, employment status, and educational level. a manner similar to that of the previous study ( Carey, Another advantage of this study is that the data were based 1988), the same advantages and disadvantages associated on a survey population which appears to represent the with Carey ( 1988) also apply to this data set. general U. S. population. Carey ( 1990)  Occupational Tenure, Employer 15.3. POPULATION MOBILITY Tenure, and Occupational Mobility  Carey ( 1990) conducted another study that was similar in scope to the study of Carey ( 1988). The January 1987 Current Population Study ( CPS) was used. This study provided data on occupational mobility and employer tenure in addition to occupational tenure. Occupational tenure was defined in Carey ( 1988) as the " the cumulative number of years a person worked in his or her current occupation, regardless of number of employees, interruptions in employment, or time spent in other locations." Employer tenure was defined as " the length of time a worker has been with the same employer," while occupational 15.3.1. Background An assessment of population mobility can assist in determining the length of time a household is exposed in a particular location. For example, the duration of exposure to site specific contamination, such as a polluted stream from which a family fishes or contaminated soil on which children play or vegetables are grown, will be directly related to the period of time residents live near the contaminated site. Information regarding population mobility is compiled and published by the U. S. Bureau of the Census ( BOC). Banks, insurance companies, credit card Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 13 companies, real estate and housing associations use The authors note that the data presented are for the residence history information. However, usually this expected time a household will stay in the same residence. information is confidential. Information compiled by the The data do not predict the expected residence time for each BOC provides information about population mobility; member of the household, which is generally expected to be however, it is difficult to determine the average residence smaller ( Israeli and Nelson, 1992). These values are more time of a homeowner or apartment dweller from this realistic estimates for the individual total residence time, information. Census data provide representations of a than the average time a household has been living at its cross section of the population at specific points in time, but current residence. The expected total residence time for a the surveys are not designed to follow individual families household is consistently less than the average current through time. The most current BOC information about residence time. This is the result of greater weighting of annual geographical mobility and mobility by State is short residence time when calculating the average total summarized in Appendix 15B. Figure 15 1 graphically residence time than when calculating the average current displays the distribution of movers by type of move. residence time ( Israeli and Nelson, 1992). When averaging Available information was provided by the Oxford total residence over a time interval, frequent movers may Development Corporation, the National Association of appear several times, but when averaging current residence Realtors ( NAR), and the BOC. According to Oxford times, each household appears only once ( Israeli and Development Corporation, a property management firm, the Nelson, 1992). According to Israeli and Nelson ( 1992), the typical residence time for an apartment dweller for their residence time distribution developed by the model is corporation has been estimated to range from 18 to 30 skewed and the median values are considerably less than the months ( S. Cameron Hendricks, Sales Department, Oxford means ( T), which are less than the average current Development Corporation, Gaithersburg, MD, personal residence times. communication with P. Wood ( Versar) August 10, 1992).

15.3.2. Key Population Mobility Studies Israeli and Nelson ( 1992)  Distribution and Expected Time of Residence for U. S. Households  In risk householders, and Hispanic householders. The data reflect assessments, the average current residence time ( time since the number of years a unit has been occupied and represent moving into current residence) has often been used as a all occupied housing units that the residents' rented or substitute for the average total residence time ( time between owned at the time of the survey. moving into and out of a residence) ( Israeli and Nelson, The results of the survey pertaining to residence time 1992). Israeli and Nelson ( 1992) have estimated of owner/ renter occupied units in the U. S. are presented in distributions of expected time of residence for U. S. Table 15 165. Using the data in Table 15 165, the households. Distributions and averages for both current and percentages of householders living in houses for specified total residence times were calculated for several housing time ranges were determined and are presented in Table 15 categories using the 1985 and 1987 BOC housing survey 166. Based on the BOC data in Table 15 165, the 50th data. The total residence time distribution was estimated percentile and the 90th percentile values were calculated for from current residence time data by modeling the moving the number of years lived in the householder's current process ( Israeli and Nelson, 1992). Israeli and Nelson house. These values were calculated by apportioning the ( 1992) estimated the average total residence time for a total sample size ( 93,147 households) to the indicated household to be approximately 4.6 years or 1/ 6 of the percentile associated with the applicable range of years expected life span ( see Table 15 163). The maximal total lived in the current home. Assuming an even distribution residence time that a given fraction of households will live within the appropriate range, the 50th and 90th percentile in the same residence is presented in Table 15 164. For values for years living in current home were determined to example, only 5 percent of the individuals in the " All be 9.1 and 32.7 years, respectively. These were then Households" category will live in the same residence for 23 rounded to 9 and 33 years. Based on the above data, the years and 95 percent will move in less than 23 years. range of 9 to 33 years is assumed to best represent a central tendency estimate of length of residence and upper U. S. Bureau of the Census ( 1993)  American Housing Survey for the United States in 1991  This survey is a national sample of 55,000 interviews in which collected data were presented owners, renters, Black percentile estimate of residence time, respectively. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 15 Descriptive statistics for subgroups defined by over 100 miles from their previous homes and 49 percent current ages were also calculated. These data, presented by purchased homes less than 10 miles away. gender, are shown in Table 15 168. The mean ROP increases from age 3 to age 12 and there is a noticeable decrease at age 24. However, there is a steady increase from age 24 through age 81. There are a few biases within this methodology that have been noted by the authors. The probability of not moving is estimated as a function only of gender and age. The Monte Carlo process assumes that this probability is independent of ( 1) the calendar year to which it is applied, and ( 2) the past history of the person being simulated. These assumptions, according to Johnson and Capel ( 1992), are not entirely correct. They believe that extreme values are a function of sample size and will, for the most part, increase as the number of simulated persons increases.

15.3.3. Relevant Population Mobility Studies National Association of Realtors ( NAR) ( 1993) The Home Buying and Selling Process  The NAR survey was Assessors are commonly interested in a number of conducted by mailing a questionnaire to 15,000 home specific types of time use data including time/ frequencies buyers throughout the U. S. who purchased homes during for bathing, showering, gardening, residence time, indoor the second half of 1993. The survey was conducted in versus outdoor time, swimming, occupational tenure, and December 1993 and 1,763 usable responses were received, population mobility. Recommendations for each of these equaling a response rate of 12 percent ( NAR, 1993). Of the are discussed below. The confidence recommendations for respondents, forty one percent were first time buyers. activity patterns is presented in Table 15 172. Home buyer names and addresses were obtained from Dataman Information Services ( DIS). DIS compiles information on residential real estate transactions from more Following are recommendations for selected than 600 counties throughout the United States using activities known to increase an individual's exposure to courthouse deed records. Most of the 250 Metropolitan certain chemicals. These activities are time spent indoors Statistical Areas are also covered in the DIS data versus outdoors and gardening, bathing and showering, compilation. swimming, residential time spent indoors and outdoors, and The home buyers were questioned on the length of traveling inside a vehicle. time they owned their previous home. Typical homebuyer ( 41%) was found to have lived in their previous home between 4 and 7 years ( Table 15 169). The survey results indicate that the average tenure of home buyers is 7.1 years based on an overall residence history of the respondents ( NAR, 1993). In addition, the median length of residence in respondents' previous homes was found to be 6 years ( see Table 15 170). The distances the respondents moved to their new homes were typically short distances. Data presented in Table 15 171 indicate that the mean distances range from 230 miles for new home buyers and repeat buyers to 8 years for first time buyers and existing home buyers. Seventeen ( 17) percent of respondents purchased homes Lehman ( 1994)  Homeowners Relocating at Faster Pace  Lehman ( 1994) presents data gathered by the Chicago Title and Trust Family Insurers. The data indicate that, in 1993, average U. S. homeowners moved every 12 years. In 1992, homeowners moved every 13.4 years and in 1991, every 14.3 years. Data from the U. S. Bureau of the Census indicate that 7 percent of the owner population moved in 1991. Based on this information, Lehman has concluded that it would take 12 years for 100 percent of owners to move. According to Lehman, Bill Harriett of the U. S. Bureau of the Census has been said that 14 years is a closer estimate for the time required for 100 percent of home owners to move. An advantage of this study is that it provides percentile data for the residential occupancy period.

15.4. RECOMMENDATIONS 15.4.1. Recommendations for Activity Patterns Time Spent Indoors Versus Outdoors and Gardening  Assessors often require knowledge of time individuals spend indoors versus outdoors. Ideally, this issue would be addressed on a site specific basis since the times are likely to vary considerably depending on the climate, residential setting ( i. e., rural versus urban), personal traits ( i. e., age, health) and personal habits. The following general recommendation is offered in the absence of site specific information. The key study by Robinson and Thomas ( 1991) compares the time use values derived in the CARB and National Studies; data are presented only for persons 12 years and older. The time use values did not differ significantly between the two studies and were averaged to provide the following recommended values. These values are applicable to Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 16 August 1997 individuals 12 years and older. Approximately 21 hrs/ day ( Table 15 62) for the 90th, 95th, and 99th percentile are spent indoors; 1.5 hrs/ day are spent outdoors, and 1.5 at 16, 40, and 200 hours/ month, respectively. hrs/ day are spent in a vehicle. Activities can vary significantly with differences in U. S. EPA's Dermal Exposure Assessment age. Special attention should be given to the activities of Document ( 1992) recommends, on the basis of judgement, populations under the age of 12 years. Timmer et al. ( 1985) an event frequency for the adult gardener, working outside: presented data on time spent in various activities for boys 1 to 2 events/ week during warmer months or about 40 and girls ages 3 11 years. The study focused on activities events/ year. An upper percentile value of 40 hours/ month performed indoors such as household work, personal care, is recommended based on Tsang and Klepeis ( 1996) eating, sleeping, school, studying, attending church, watching television, and engaging in household conversations. The average times spent in each indoor activity ( and half the times spent in each activity which could have occurred indoors or outdoors) were summed. This procedure resulted in the following recommendations:

° Indoor activities accounted for about 78 percent of the total time in weekdays and 70 percent total time in weekend days. The corresponding times spent indoors are 19 hrs/ day for weekdays and 17 hrs/ day on weekends.

° Outdoor activities accounted for about 22 percent of children's time during weekdays and 30 percent during the weekend. The corresponding times spent outdoors are 5 hrs/ day for weekdays and 7 hrs/ day on weekends.

Assessors evaluating soil exposures are commonly interested in data on gardening times and frequencies. No data specific to time spent gardening could be found; thus, no firm recommendation could be made. However, three sets of data were found which indirectly relate to this issue which the assessor can consider in deriving time estimates for gardening:

° Robinson and Thomas ( 1991) estimated the time spent in " other outdoor activities" ( Table 15 8) as 1 hr/ day. These data apply to populations 12 years and older.

° Hill ( 1985) estimated that time spent in " house work and/ or yard work" ( Table 15 153) as 2 hr/ day. These data apply to adult populations.

C Tsang and Klepeis ( 1996) estimated that time spent in the garden or other circumstances working with soil for persons 18 64 years old Baths and Showers  In the NHAPS study, 649 (~ 7 percent) of the total participants indicated either taking or giving at least one bath in a day. Those 649 respondents were subsequently asked the number of times they took or gave a bath in one day. The majority, 459 of 649 respondents, recorded taking or giving one bath in a day. These results are presented in Table 15 24. The recommended bathing duration is 20 minutes. This is a 50th percentile value based on the NHAPS distribution shown on Table 15 26; the reported 90th percentile value is 45 minutes. The recommended shower frequency of one shower per day is based on the NHAPS data summarized in Table 15 19. This table showed that 3,594 of the 9,386 total participants indicated taking at least one shower the previous day. When asked the number of actual showers taken the previous day, the reported results ranged from one to ten showers; a majority ( 76 percent), of those 3,549 respondents, reported taking one shower the previous day. The NHAPS data shown on Table 15 19, Table 15 24, and Table 15 26 provide information grouped according to gender, age, race, employment, education, day of the week, seasonal conditions, and health conditions such as asthma, angina, and bronchitis/ emphysema. Recommendations for showering duration are based on the key study conducted by Tsang and Klepeis ( 1996). A recommended value for average showering time is 10 minutes ( Table 15 20) based on professional judgement. This approximates the average showering value ( 8 minutes) of James and Knuiman ( 1987) ( Table 15 18). The recommended 50th percentile value is 15 minutes, and the 95th percentile value is 35 minutes ( Table 15 21). Although these values are slightly higher than those of James and Knuiman ( 1987), they are believed to be more representative of U. S. households. Swimming  Data for swimming frequency is taken from the NHAPS Study ( Tsang ad Klepeis, 1996). Of 9,386 participants, 653 ( about 7 percent), answered yes to Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 17 the question " in the past month, did you swim in a region, day of the week, season, and health condition of freshwater pool?". The results to this question are respondents. summarized in Table 15 65. The recorded number of times respondents swam in the past month ranged from 1 to 60 with the greatest number of respondents, 147 ( 23 percent), The median occupational tenure of the working reporting they swam one time per month. Thus, the population ( 109.1 million people) ages 16 years of age and recommended swimming frequency is one event/ month for older in January 1987 was 6.6 years ( Carey, 1988). Since the general population. The recommended swimming the occupational tenure varies significantly according to age duration, 60 minutes per swimming event, is based on the it is recommended to use the age dependent values NHAPS distribution shown on Table 15 67. Sixty minutes presented in Carey's 1988 study ( Table 15 158). When age is based on the 50th percentile value; the 90th percentile cannot be determined, it is recommended to use the median value is 180 minutes per swimming event ( based on one tenure value of 6.6 years for working men and women 16 event/ month); and the 99th percentile value is 181 minutes. years and older. For persons 70 years and older, a tenure This value ( 181) indicates that more than 180 minutes were value of 21.9 years is recommended for a working lifetime. spent. A value of 30.5 years and 18.8 years is recommended for In addition, users can obtain frequency and duration men and women, respectively. Part time employment, race data grouped according to gender, age, race, employment, and the position held are important to consider in education, day of the week, and season. Frequency and determining occupational tenure. The ratings indicating duration data is also available in Table 15 65 and Table 15 confidence in the occupational mobility recommendations 67, for swimmer respondents reporting health conditions are presented in Table 15 173. It should be noted that the such as asthma, angina, and bronchitis/ emphysema. recommended values are not for use in evaluating job Residential Time Spent Indoors and Outdoors  The recommendations for time spent indoors at one's residence is 16.4 hours/ day. This is based on the NHAPS data summarized in Table 15 131 which records the 50th 15.4.3. Recommendations: Population Mobility percentile value of 985.0 minutes per day ( 16.4 hours/ day); and a 90th percentile value of 1,395 minutes per day ( 23.3 hours/ day). The recommended value for time spent outdoors at one's residence is 2 hours per day based on Table 15 102 ( generated by the NHAPS data). Values of 105 minutes per day for the 50th percentile and 362 minutes per day for the 90th percentile are shown in Table 15 102. Traveling Inside a Vehicle  The recommendation for time spent in a vehicle is 1 hour and 20 minutes per day. This recommendation is based on two studies and ( 1) Robinson and Thomas ( 1991) and ( 2) The NHAPS data. The Robinson and Thomas study evaluated two independent studies, the CARB and the National Study. They respectively reported mean durations for time spent in a vehicle as 98 and 87 minutes per day which averages to 92 minutes per day or about 1.5 hours per day. The NHAPS data, as summarized on Table 15 133, provide a 50th percentile value of 70 minutes per day ( or 1 hour and 10 minutes) and a 90th percentile value of 190 minutes per day. Thus, the averaged value from these two studies is about 1 hour and 20 minutes. NHAPS data is grouped according to gender, race, age, employment status, census 15.4.2. Recommendations: Occupational Mobility tenure. These data can be used for determining time spent in an occupation and not for time spent at a specific job site.

There are three key studies from which the population mobility recommendations were derived: Israeli and Nelson ( 1992), U. S. Bureau of the Census ( 1993)  and Johnson and Capel ( 1992). Each study used a unique approach to estimate the length of time a person resides in a household. The respective approaches were to ( 1) average current and total residence time; ( 2) model current residence time; and ( 3) determine the residential occupancy period. A summary of the approaches used and values recommended by each of these studies is presented in Table 15 174. The three studies provide residence time estimates that are very similar to the 9 year ( 50th percentile) and 30 year ( 95th percentile). Tables 15 163 and 15 164 show residence times for different types of residences and are recommended where assessors are interested in specific types of residences. The ratings indicating confidence in the population mobility recommendations is presented in Table 15 175. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 18 August 1997 15.4.4. Summary of Recommended Activity Factors Table 15 176 includes a summation of the Lehman, H. J. ( 1994) Homeowners relocating at faster recommended activity pattern factors presented in this pace. Virginia Homes Newspaper, Saturday, June 15, section and the studies which provided data on the specific P. E1. activities. The type of activities include indoor activities, National Association of Realtors ( NAR). ( 1993) The outdoor activities, time inside a vehicle, taking a bath or homebuying and selling process: 1993. The Real shower, swimming, working at a specific occupation, and Estate Business Series. Washington, DC: NAR. residing in a particular location. Palisade. ( 1992) @ Risk users guide. Newfield, NY:

15.5. REFERENCES FOR CHAPTER 15 AIHC. ( 1994) Exposure factors sourcebook. Cleveland State University, Communication Research Washington, DC. American Industrial Health Center. Council. Robinson, J. P; Thomas, J. ( 1991) Time spent in Bureau of Labor Statistics. ( 1987) Most occupational activities, locations, and microenvironments: a exposures are voluntary. Washington, DC: U. S. California National Comparison Project report. Las Department of Labor. Vegas, NV: U. S. Environmental Protection Agency, Carey, M. ( 1988) Occupational tenure in 1987: Many Environmental Monitoring Systems Laboratory. workers have remained in their fields. Monthly Labor Sell, J. ( 1989) The use of children's activity patterns in Review. October 1988. 3 12. the development of a strategy for soil sampling in Carey, M. ( 1990) Occupational tenure, employer tenure, West Central Phoenix. The Arizona Department of and occupational mobility. Occupational Outlook Environmental Quality, Phoenix, Arizona. Quarterly. Summer 1990: 55 60. Sexton, K; Ryan, P. B. ( 1987) Assessment of human Hill, M. S. ( 1985) Patterns of time use. In: Juster, F. T.; exposure to air pollution: methods, measurements, Stafford, F. P., eds. Time, goods, and well being. Ann and models. In: Watson, A.; Bates, R. R.; Kennedy, Arbor, MI: University of Michigan, Survey Research D., eds. Air pollution, the automobile and public Center, Institute for Social Research, pp. 133 166. health: research opportunities for quantifying risk. Israeli, M; Nelson, C. B. ( 1992) Distribution and Washington, DC: National Academy of Sciences expected time of residence for U. S. households. Risk Press. Anal. 12( 1): 65 72. Spencer, G. ( 1989) Projections of the populations of the James, I. R.; Knuiman, M. W. ( 1987) An application of United States by age, sex, and race: 1988 to 2080. Bayes methodology to the analysis of diary records Washington, DC: U. S. Department of Commerce, from a water use study. J. Am. Sta. Assoc. Bureau of the Census. Series, P 25, No. 1018. 82( 399): 705 711. Tarshis, B. ( 1981) The " Average American" book. New Johnson, T. and Capel, J. ( 1992) A monte carlo York, NY: New American Library, p. 191. approach to simulating residential occupancy periods Timmer, S. G.; Eccles, J.; O'Brien, K. ( 1985) How and its application to the general U. S. population. children use time. In: Juster, F. T.; Stafford, F. P.; eds. Research Triangle Park, NC: U. S. Environmental Time, goods, and well being. Ann Arbor, MI: Protection Agency, Office of Air Quality and University of Michigan, Survey Research Center, Standards. Institute for Social Research, pp. 353 380. Juster, F. T.; Hill, M. S.; Stafford, F. P.; Parsons, J. E. Tsang, A. M.; Klepeis, N. E. ( 1996) Results tables from a ( 1983) Study description. 1975 1981 time use detailed analysis of the National Human Activity longitudinal panel study. Ann Arbor, MI: The Pattern Survey ( NHAPS) response. Draft Report University of Michigan, Survey Research Center, prepared for the U. S. Environmental Protection Institute for Social Research. Agency by Lockheed Martin, Contract No. 68 W6 Juster, F. T. ( 1985) A note on recent changes in time use. 001, Delivery Order No. 13. In: Juster, F. T.; Stafford, F. P.; eds. Time, goods, and well being. Ann Arbor, MI: University of Michigan, Survey Research Center, Institute for Social Research. pp. 313 330.

Palisade Corporation. Robinson, J. P. ( 1977) Changes in Americans' use of time: 1965 1975. A progress report. Cleveland, OH: Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 19 U. S. Bureau of the Census. ( 1993) American Housing Wiley, J. A.; Robinson, J. P.; Cheng, Y.; Piazza, T.; Stork, Survey for the United States in 1991. Washington, L.; Plasden, K. ( 1991) Study of children's activity DC: U. S. Government Printing Office. patterns. California Environmental Protection U. S. Bureau of the Census. ( 1993) Geographical Agency, Air Resources Board Research Division. mobility: March 1991 to March 1992. Current Sacramento, CA. population reports P. 20 473. U. S. EPA. ( 1989) Exposure factors handbook. Washington, DC: Office of Health and Environmental Assessment. EPA/ 600/ 08 89/ 043. U. S. EPA. ( 1992) Dermal exposure assessment: principles and applications. Washington, DC: Office of Health and Environmental Assessment. EPA No. 600/ 8 91 011B. Interim Report. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 20 August 1997 Table 15 1. Time Use Table Locator Guide Percentile Basis Population Application Study Table Averages Activity Children 3 17 yrs National Timmer et al., 1985 15 2 Distribution Activity Children and Teens National Timmer et al., 1985 15 3 Distribution Showering Adults Foreign Australia James and Knuiman, 1987 15 4 Tsang and Klepeis, 1996 15 24 Averages Activity Adults 18 64 yrs National Robinson and Thomas, 1991 15 5 Averages Activity Adults 18 64 yrs Regional CA Robinson and Thomas, 1991 15 5 Averages Microenvironment Adults 18 64 yrs National/ Regional CA Robinson and Thomas, 1991 15 6 Averages Microenvironment Children and Adult Regional California Robinson and Thomas, 1991 15 7 to 15 10 Averages Microenvironment Children and Adults National Robinson and Thomas, 1991 15 7 to 15 10 Averages Activity Infants and Children Regional California Wiley et al., 1991 15 11 Distribution Activity Infants and Children Regional California Wiley et al., 1991 15 12 Averages Activity by season Infants and Children Regional California Wiley et al., 1991 15 13 Averages Microenvironment Infants and Children Regional California Wiley et al., 1991 15 14 Distribution Microenvironment Infant and Children Regional California Wiley et al., 1991 15 15 Averages Microenvironment by Infants and Children Regional California Wiley et al., 1991 15 16 season Distribution Microenvironment near Infant and Children Regional California Wiley et al., 1991 15 17 pollutant Averages Bathing and swimming Adults Regional National USEPA, 1992 15 18 Tsang and Klepeis, 1996 15 22, 15 63 Average Activity by employment Adults National Robinson, 1977 15 147 Averages Occupational Tenure by Teens and Adults National Carey, 1988 15 157 race and gender Averages Occupational Tenure by Teens and Adults National Carey, 1988 15 158 employment and gender Distribution Occupational Tenure by Teens and Adults National Carey, 1988 15 159 employment Distribution Occupational Mobility by Teens and Adults National Carey, 1990 15 160 age Distribution Population Mobility by All ages National Census, 1993 Figure 15 1 locale Averages Residence Time by All ages National Israeli and Nelson, 1992 15 161 region, setting Distribution Residence Time by All ages National Israeli and Nelson, 1992 15 162 region, setting Distribution Residence Time by year All ages National Census, 1993 15 163 moved in Distribution Residence Time by years All ages National Census, 1993 15 164 in current home Distribution Residence Time by All ages National Johnson and Capel, 1992 15 165 gender Distribution Residence Time by age All ages National Johnson and Capel, 1992 15 166 Distribution Residence Time by years All ages National NAR, 1993 15 167 in previous house Distribution Residence Time by tenure All ages National NAR, 1993 15 168 in previous home Distribution Relocation Distance All ages National NAR, 1993 15 169 Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 21 Table 15 2. Mean Time Spent ( minutes) Performing Major Activities Grouped by Age, Sex and Type of Day Activity Age ( 3 11 years) Age ( 12 17 years)

Duration of Time ( mins/ day) Duration of Time ( mins/ day)

Weekdays Weekends Weekdays Weekends Boys Girls Boys Girls Boys Girls Boys Girls ( n= 118) ( n= 111) ( n= 118) ( n= 111) ( n= 77) ( n= 83) ( n= 77) ( n= 83)

Market Work 16 0 7 4 23 21 58 25 Household Work 17 21 32 43 16 40 46 89 Personal Care 43 44 42 50 48 71 35 76 Eating 81 78 78 84 73 65 58 75 Sleeping 584 590 625 619 504 478 550 612 School 252 259   314 342

Studying 14 19 4 9 29 37 25 25 Church 7 4 53 61 3 7 40 36 Visiting 16 9 23 37 17 25 46 53 Sports 25 12 33 23 52 37 65 26 Outdoors 10 7 30 23 10 10 36 19 Hobbies 3 1 3 4 7 4 4 7 Art Activities 4 4 4 4 12 6 11 9 Playing 137 115 177 166 37 13 35 24 TV 117 128 181 122 143 108 187 140 Reading 9 7 12 10 10 13 12 19 Household Conversations 10 11 14 9 21 30 24 30 Other Passive Leisure 9 14 16 17 21 14 43 33 NA 22 25 20 29 14 17 10 4 a Percent of Time Accounted for 94% 92% 93% 89% 93% 92% 88% 89% by Activities Above a NA = Unknown Source: Timmer et al., 1985. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 22 August 1997 Table 15 3. Mean Time Spent ( minutes) in Major Activities Grouped by Type of Day for Five Different Age Groups Time Duration ( mins) Significant Effectsa Weekday Weekend Age ( years) 3 5 6 8 9 11 12 15 17 3 5 6 8 9 11 12 14 15 17 14 Activities Market Work  14 8 14 28  4 10 29 48 Personal Care 41 49 40 56 60 47 45 44 60 51 A, S, AxS ( F> M)

Household Work 14 15 18 27 34 17 27 51 72 60 A, S, AxS ( F> M)

Eating 82 81 73 69 67 81 80 78 68 65 A Sleeping 630 595 548 473 499 634 641 596 604 562 A School 137 292 315 344 314

Studying 2 8 29 33 33 1 2 12 15 30 A Church 4 9 9 9 3 55 56 53 32 37 A Visiting 14 15 10 21 20 10 8 13 22 56 A ( Weekend only)

Sports 5 24 21 40 46 3 30 42 51 37 A, S ( M> F)

Outdoor activities 4 9 8 7 11 8 23 39 25 26 Hobbies 0 2 2 4 6 1 5 3 8 3 Art Activities 5 4 3 3 12 4 4 4 7 10 Other Passive Leisure 9 1 2 6 4 6 10 7 10 18 A Playing 218 111 65 31 14 267 180 92 35 21 A, S ( M> F)

TV 111 99 146 142 108 122 136 185 169 157 A, S, AxS ( M> F)

Reading 5 5 9 10 12 4 9 10 10 18 A Being read to 2 2 0 0 0 3 2 0 0 0 A NA 30 14 23 25 7 52 7 14 4 9 A a Effects are significant for weekdays and weekends, unless otherwise specified A = age effect, P< 0.05, for both weekdays and weekend activities; S = sex effect P< 0.05, F> M, M> F = females spend more time than males, or vice versa; and AxS = age by sex interaction, P< 0.05. Source: Timmer et al., 1985. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 23 Table 15 4. Cumulative Frequency Distribution of Average Shower Duration for 2,550 Households Shower duration ( minutes) Cumulative frequency ( percentage)

1 0.2 2 0.8 3 3.1 4 9.6 5 22.1 6 37.5 7 51.6 8 62.5 9 72.0 10 79.4 11 84.5 12 88.4 13 90.6 14 92.3 15 93.7 16 94.9 17 95.7 18 96.7 19 97.6 20 98.0 < 20 100.0 Source: Adapted from James and Knuiman, 1987. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 24 August 1997 Table 15 5. Mean Time Spent ( minutes/ day) in Ten Major Activity Categories Grouped by Total Sample and Gender for the CARB and National Studies ( age 18 64 years)

Time Duration ( mins/ day)

Activity Category Activity CARB National CARB National a Codes ( 1987 88) ( 1985) ( 1987 88) ( 1985) b Total Sample Men Women Men Women n = 1,359 n = 1,980 n = 639 n = 720 n = 921 n = 1,059 c Paid Work 00 09 273 252 346 200 323 190 Household Work 10 19 102 118 68 137 79 155 Child Care 20 29 23 25 12 36 11 43 Obtaining Goods and 30 39 61 55 48 73 44 62 Services Personal Needs and Care 40 49 642 642 630 655 636 645 Education and Training 50 59 22 19 25 20 21 16 Organizational Activities 60 69 12 17 11 13 12 20 Entertainment/ Social 70 79 60 62 57 55 64 62 Activities Recreation 80 89 43 50 53 31 69 43 Communication 90 99 202 196 192 214 197 194 a, b Time use for components of activity categories and codes are shown in Appendix Table 15A 6. c n = total diary days. Source: Robinson and Thomas, 1991 Table 15 6. Total Mean Time Spent at Three Major Locations Grouped by Total Sample and Gender for the CARB and National Study ( ages 18 64 years)

Location Code CARB National CARB National a b ( 1987 88) ( 1985) ( 1987 88) ( 1985)

Total Sample Men Women Men Women n = 1359 n = 1980 n = 39 n = 720 n = 921 n = 1059 c c c c c c At Home WC01 13 892 954 822 963 886 1022 Away From Home WC21 40 430 384 487 371 445 324 Travel WC51 61 116 94 130 102 101 87 Not Ascertained WC99 2 8 1 4 8 7 Total Time 1440 1440 1440 1440 1440 1440 a, b Time use data for the 44 components of location and location codes are presented in Appendix Table 15A 7. c n = total diary days. Source: Robinson and Thomas, 1991. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 25 Table 15 7. Mean Time Spent at Three Locations for both CARB and National Studies ( ages 12 years and older)

Mean duration ( mins/ day)

Location Category CARB National ( n = 1762) S. E. ( n = 2762) S. E. b a b Indoor 1255 28 1279 21 c c Outdoor 86 5 74 4 d d In Vehicle 98 4 87 2 d d Total Time Spent 1440 1440 S. E. = Standard Error of Mean a Weighted Number  National sample population was weighted to obtain a ratio of 46.5 males and 53.5 females, in equal b proportion for each day of the week, and for each quarter of the year. Difference between the mean values for the CARB and national studies is not statistically significant. c Difference between the mean values for the CARB and national studies is statistically significant at the 0.05 level. d Source: Robinson and Thomas, 1991. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 26 August 1997 Table 15 8. Mean Time Spent ( minutes/ day) in Various Microenvironments Grouped by Total Population and Gender ( 12 years and over) in the National and CARB Data National Data Mean Duration ( mins/ day) ( standard error) a Microenvironment Men Men Women Women Total Total N = 1284 " Doer" N = 1478 " Doer" N = 2762 " Doer" b c b b Autoplaces 5 ( 1) 90 1 ( 0) 35 3 ( 0) 66 Restaurant/ bar 22 ( 2) 73 20 ( 2) 79 21 ( 1) 77 In vehicle 92 ( 3) 99 82 ( 3) 94 87 ( 2) 97 In Vehicle/ other 1 ( 1) 166 1 ( 0) 69 1 ( 0) 91 Physical/ outdoors 24 ( 3) 139 11 ( 2) 101 17 ( 2) 135 Physical/ indoors 11 ( 1) 84 6 ( 1) 57 8 ( 1) 74 Work/ study residence 17 ( 2) 153 15 ( 2) 150 16 ( 1) 142 Work/ study other 221 ( 10) 429 142 ( 7) 384 179 ( 6) 390 Cooking 14 ( 1) 35 52 ( 2) 67 34 ( 1) 57 Other activities/ kitchen 54 ( 3) 69 90 ( 4) 102 73 ( 2) 88 Chores/ child 88 ( 3) 89 153 ( 5) 154 123 93) 124 Shop/ errand 23 ( 2) 56 38 ( 2) 74 31 ( 1) 67 Other/ outdoors 70 ( 6) 131 43 ( 4) 97 56 ( 4) 120 Social/ cultural 71 ( 4) 118 75 ( 4) 110 73 ( 3) 118 Leisure eat/ indoors 235 ( 8) 241 215 ( 7) 224 224 ( 5) 232 Sleep/ indoors 491 ( 14) 492 496 ( 11) 497 494 ( 9) 495 CARB Data Mean Duration ( mins/ day) ( standard error) a Microenvironment Men Men Women Women Total Total N = 867 " Doer" N = 895 " Doer" N = 1762 " Doer" b c b b Autoplaces 31 ( 8) 142 9 ( 2) 50 20 ( 4) 108 Restaurant/ bar 45 ( 4) 106 28 ( 3) 86 36 ( 3) 102 In vehicle 105 ( 7) 119 85 ( 4) 100 95 ( 4) 111 In Vehicle/ other 4 ( 1) 79 3 ( 2) 106 3 ( 1) 94 Physical/ outdoors 25 ( 3) 131 8 ( 1) 86 17 ( 2) 107 Physical/ indoors 8 ( 1) 63 5 ( 1) 70 7 ( 1) 68 Work/ study residence 14 ( 3) 126 11 ( 2) 120 13 ( 2) 131 Work/ study other 213 ( 14) 398 156 ( 11) 383 184 ( 9) 450 Cooking 12 ( 1) 43 42 ( 2) 65 27 ( 1) 55 Other activities/ kitchen 38 ( 3) 65 60 ( 4) 82 49 ( 2) 74 Chores/ child 66 ( 4) 75 134 ( 6) 140 100 ( 4) 109 Shop/ errand 21 ( 3) 61 41 ( 3) 78 31 ( 2) 70 Other/ outdoors 95 ( 9) 153 44 ( 4) 82 69 ( 5) 117 Social/ cultural 47 ( 4) 112 59 ( 5) 114 53 ( 3) 112 Leisure eat/ indoors 223 ( 10) 240 251 ( 10) 263 237 ( 7) 250 Sleep/ indoors 492 ( 17) 499 504 ( 15) 506 498 ( 12) 501 a Standard error of the mean b Weighted number c Doer = Respondents who reported participating in each activity/ location spent in microenvironments. Source: Robinson and Thomas, 1991. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 27 Table 15 9. Mean Time Spent ( minutes/ day) in Various Microenvironments by Type of Day for the California and National Surveys ( sample population ages 12 years and older)

Weekday Mean Duration ( standard error) Mean Duration for " Doer" Microenvironment ( mins/ day) ( mins/ day) a b CARB NAT ( n= 1259) ( n= 1973) CARB NAT c c 1 Autoplaces 21 ( 5) 3 ( 1) 108 73 2 Restaurant/ Bar 29 ( 3) 20 ( 2) 83 73 3 In Vehicle/ Internal Combustion 90 ( 5) 85 ( 2) 104 95 4 In Vehicle/ Other 3 ( 1) 1 ( 0) 71 116 5 Physical/ Outdoors 14 ( 2) 15 ( 2) 106 118 6 Physical/ Indoors 7 ( 1) 8 ( 1) 64 68 7 Work/ Study Residence 14 ( 2) 16 ( 2) 116 147 8 Work/ Study Other 228 ( 11) 225 ( 8) 401 415 9 Cooking 27 ( 2) 35 ( 2) 58 57 10 Other Activities/ Kitchen 51 ( 3) 73 ( 3) 76 87 11 Chores/ Child 99 ( 5) 124 ( 4) 108 125 12 Shop/ Errand 30 ( 2) 30 ( 2) 67 63 13 Other/ Outdoors 67 ( 6) 51 ( 4) 117 107 14 Social/ Cultural 42 ( 3) 62 ( 3) 99 101 15 Leisure Eat/ Indoors 230 ( 9) 211 ( 6) 244 218 16 Sleep/ Indoors 490 ( 14) 481 ( 10) 495 483 Weekend Mean Duration ( standard error) Mean Duration for " Doer" Microenvironment ( mins/ day) ( mins/ day) a b CARB NAT ( n= 503) ( n= 789) CARB NAT c c 1 Autoplaces 19 ( 4) 3 ( 1) 82 62 2 Restaurant/ Bar 55 ( 6) 23 ( 2) 127 84 3 In Vehicle/ Internal Combustion 108 ( 8) 91 ( 6) 125 100 4 In Vehicle/ Other 5 ( 3) 0 ( 0) 130 30 5 Physical/ Outdoors 23 ( 3) 23 ( 4) 134 132 6 Physical/ Indoors 7 ( 1) 9 ( 2) 72 80 7 Work/ Study Residence 10 ( 2) 15 ( 3) 155 165 8 Work/ Study Other 74 ( 11) 64 ( 6) 328 361 9 Cooking 27 ( 2) 34 ( 2) 60 55 10 Other Activities/ Kitchen 44 ( 3) 73 ( 4) 71 90 11 Chores/ Child 103 ( 7) 120 ( 5) 114 121 12 Shop/ Errand 35 ( 4) 35 ( 3) 81 75 13 Other/ Outdoors 74 ( 7) 67 ( 7) 126 132 14 Social/ Cultural 79 ( 7) 99 ( 6) 140 141 15 Leisure Eat/ Indoors 256 ( 12) 257 ( 11) 273 268 16 Sleep/ Indoors 520 ( 20) 525 ( 17) 521 525 Standard Error of Mean a Doer = Respondent who reported participating in each activity/ location spent in microenvironments. b Weighted Number c Source: Robinson and Thomas, 1991. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 28 August 1997 Table 15 10. Mean Time Spent ( minutes/ day) in Various Microenvironments by Age Groups for the National and California Surveys Microenvironment National Data Mean Duration ( Standard Error) a Age 12 17 years N= 340b " Doer" c Age 18 24 years N= 340 " Doer" Age 24 44 years N= 340 " Doer" Age 45 64 years N= 340 " Doer" Age 65+ years N= 340 " Doer"

Autoplaces 2 ( 1) 73 7 ( 2) 137 2 ( 1) 43 4 ( 1) 73 4 ( 2) 57 Restaurant/ bar 9 ( 2) 60 28 ( 3) 70 25 ( 3) 86 19 ( 2) 67 20 ( 5) 74 In vehicle/ internal combustion 79 ( 7) 88 103 ( 8) 109 94 ( 4) 101 82 ( 5) 91 62 ( 5) 80 In vehicle/ other 0 ( 0) 12 1 ( 1) 160 1 ( 0) 80 1 ( 1) 198 1 ( 1) 277 Physical/ outdoors 32 ( 8) 130 17 ( 4) 110 19 ( 4) 164 7 ( 1) 79 15 ( 4) 81 Physical/ indoors 15 ( 3) 87 8 ( 2) 76 7 ( 1) 71 7 ( 2) 77 7 ( 1) 51 Work/ studyresidence 22 ( 4) 82 19 ( 6) 185 16 ( 2) 181 9 ( 2) 169 5 ( 3) 297 Work/ study other 159 ( 14) 354 207 ( 20) 391 220 ( 11) 422 180 ( 13) 429 35 ( 6) 341 Cooking 11 ( 3) 40 18 ( 2) 39 38 ( 2) 57 43 ( 3) 64 50 ( 5) 65 Other activities/ kitchen 53 ( 4) 64 42 ( 3) 55 70 ( 4) 86 90 ( 6) 101 108 ( 9) 119 Chores/ child 91 ( 7) 92 124 ( 9) 125 133 ( 6) 134 121 ( 6) 122 119 ( 7) 121 Shop/ errands 26 ( 4) 68 31 ( 4) 65 33 ( 2) 66 33 ( 3) 67 35 ( 5) 69 Other/ outdoors 70 ( 13) 129 34 ( 4) 84 48 ( 6) 105 60 ( 7) 118 82 ( 13) 140 Social/ cultural 87 ( 10) 120 100 ( 12) 141 56 ( 3) 94 73 ( 6) 116 85 ( 8) 122 Leisure eat/ indoors 237 ( 16) 242 181 ( 11) 189 200 ( 8) 208 238 ( 11) 244 303 ( 20) 312 Sleep/ indoors 548 ( 31) 551 511 ( 26) 512 479 ( 14) 480 472 ( 15) 472 507 ( 26) 509 Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 29 Table 15 10. Mean Time Spent ( minutes/ day) in Various Microenvironments by Age Groups ( continued)

Microenvironment CARB Data Mean Duration ( Standard Error) a Age 12 17 years N= 183b " Doer" c Age 18 24 years N= 250 " Doer" Age 24 44 years N= 749 " Doer" Age 45 64 years N= 406 " Doer" Age 65+

years N= 158 " Doer"

Autoplaces 16 ( 8) 124 16 ( 4) 71 25 ( 9) 114 20 ( 5) 94 9 ( 2) 53 Restaurant/ bar 16 ( 4) 44 40 ( 8) 98 44 ( 5) 116 31 ( 4) 82 25 ( 7) 99 In vehicle/ internal combustion 78 ( 11) 89 111 ( 13) 122 98 ( 5) 111 100 ( 11) 117 63 ( 8) 89 In vehicle/ other 1 ( 0) 19 3 ( 1) 60 5 ( 2) 143 2 ( 1) 56 2 ( 1) 53 Physical/ outdoors 32 ( 7) 110 13 ( 3) 88 17 ( 3) 128 14 ( 3) 123 15 ( 4) 104 Physical/ indoors 20 ( 4) 65 5 ( 2) 77 6 ( 1) 61 5 ( 1) 77 3 ( 1) 48 Work/ study residence 25 ( 5) 76 30 ( 11) 161 7 ( 2) 137 10 ( 3) 139 5 ( 3) 195 Work/ study other 196 ( 30) 339 201 ( 24) 344 215 ( 14) 410 173 ( 20) 429 30 ( 11) 336 Cooking 3 ( 1) 19 14 ( 2) 40 32 ( 2) 59 31 ( 3) 68 41 ( 7) 69 Other activities/ kitchen 31 ( 4) 51 31 ( 5) 55 43 ( 3) 65 62 ( 6) 91 97 ( 14) 119 Chores/ child 72 ( 11) 77 79 ( 8) 85 110 ( 6) 119 99 ( 8) 109 123 ( 15) 141 Shop/ errands 14 ( 3) 50 35 ( 7) 71 33 ( 4) 71 32 ( 3) 77 35 ( 5) 76 Other/ outdoors 58 ( 8) 78 80 ( 15) 130 68 ( 8) 127 76 ( 12) 134 55 ( 7) 101 Social/ cultural 63 ( 14) 109 65 ( 10) 110 50 ( 5) 122 50 ( 5) 107 49 ( 7) 114 Leisure eat/ indoors 260 ( 27) 270 211 ( 19) 234 202 ( 9) 215 248 ( 15) 261 386 ( 34) 394 Sleep/ indoors 557 ( 44) 560 506 ( 30) 510 487 ( 17) 491 485 ( 23) 491 502 ( 31) 502 Standard error.

a All N's are weighted number.

b Doer = Respondents who reported participating in each activity/ location spent in microenvironments.

c Source: Robinson and Thomas, 1991. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 30 August 1997 Table 15 11. Mean Time ( minutes/ day) Children Spent in Ten Major Activity Categories for All Respondents Activity Category ( mins/ day) Doing ( mins/ day) ( mins/ day) ( mins/ day) ( code) Mean Duration Duration Duration Detailed Activity with Duration % for Doers for Doer for Doers Highest Avg. Minutes Mean Median Maximum b Work related 10 25 39 30 405 Eating at work/ school/ daycare ( 06) a Household 53 86 61 40 602 Travel to household ( 199)

Childcare < 1 < 1 83 30 290 Other child care ( 27)

Goods/ Services 21 26 81 60 450 Errands ( 38)

Personal Needs and Care 794 100 794 770 1440 Night sleep ( 45) c Education 110 35 316 335 790 School classes ( 50) d Organizational Activities 4 4 111 105 435 Attend meetings ( 60)

Entertain/ Social 15 17 87 60 490 Visiting with others ( 75)

Recreation 239 92 260 240 835 Games ( 87)

Communication/ Passive 192 93 205 180 898 TV use ( 91) Leisure Don't know/ Not coded 2 4 41 15 600

All Activities 1441 e Includes eating at school or daycare, an activity not grouped under the " education activities" ( codes 50 59, 549). a " Doers" indicate the respondents who reported participating in each activity category. b Personal care includes night sleepand daytime naps, eating, travel for personal care. c Education includes student and other classes, homework, library, travel for education. d Column total may not sum to 1440 due to rounding error e Source: Wiley et al., 1991.

Table 15 12. Mean Time Children Spent in Ten Major Activity Categories Grouped by Age and Gender Activity Category Mean Duration ( minutes/ day)

Boys Girls 0 2 yrs 3 5 yrs 6 8 yrs 9 11 yrs Ages 0 2 yrs 3 5 yrs 6 8 yrs 9 11 yrs Ages All All Work related 4 9 14 12 10 5 12 11 10 10 Household 33 45 55 65 48 58 44 51 76 57 Childcare 0 0 0 1 < 1 0 0 0 4 1 Goods/ Services 20 22 19 14 19 22 25 23 22 23 Personal Needs and Care 914 799 736 690 792 906 816 766 701 797 a Education 60 67 171 138 106 41 95 150 176 115 b Organizational Activities 1 3 7 6 4 6 1 4 6 4 Entertainment/ Social 3 15 5 34 13 5 16 9 36 17 Recreation 217 311 236 229 250 223 255 238 194 228 Communication/ Passive 187 166 195 250 197 171 173 189 213 186 Leisure Don't know/ Not coded 1 4 1 1 2 3 1 < 1 3 2 All Activities 1440 1441 1439 1440 1442 1440 1438 1441 1441 1440 c Sample Sizes 172 151 145 156 624 141 151 124 160 576 Unweighted N's Personal needs and care includes night sleep and daytime naps, eating, travel for personal care. a Education includes student and other classes, homework, library, travel for education. b The column totals may differ from 1440 due to rounding error. C Source: Wiley et al., 1991. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 31 Table 15 13. Mean Time Children Spent in Ten Major Activity Categories Grouped by Seasons and Regions Activity Category Mean Duration ( minutes/ day)

Season Region of California Winter Spring Summer Fall All So. Bay Rest of All ( Jan Mar) ( Apr June) ( July Sept) ( Oct Dec) Seasons Coast Area State Regions Work related 10 10 6 13 10 10 10 8 10 Household 47 58 53 52 53 45 62 55 53 Childcare < 1 1 < 1 < 1 < 1 < 1 < 1 1 < 1 Goods/ Services 19 17 26 23 21 20 21 23 21 Personal Needs and 799 774 815 789 794 799 785 794 794 Carea Education 124 137 49 131 110 109 115 109 110 b Organizational 3 5 5 3 4 2 6 6 4 Activities Entertainment/ Social 14 12 12 22 15 17 10 16 15 Recreation 221 243 282 211 239 230 241 249 239 Communication/ Passi 203 180 189 195 192 206 190 175 192 ve Leisure Don't know/ Not < 1 2 3 < 1 2 1 1 3 2 coded All Activities 1442 1439 1441 1441 1441 1440 1442 1439 1441 c Sample Sizes 318 204 407 271 1200 224 263 713 1200 ( Unweighted)

Personal needs and care includes night sleep and daytime naps, eating, travel for personal care. a Education includes student and other classes, homework, library, travel for education. B The column totals may not be equal to 1440 due to rounding error. c Source: Wiley et al., 1991.

Table 15 14. Mean Time Children Spent in Six Major Location Categories for All Respondents ( minutes/ day)

Location Category Duration % Duration Duration Duration for Detailed Location with Highest Avg. Mean Mean Median Maximum ( mins) Doing for Doers for Doers Doers Time ( mins) ( mins) ( mins)

Home 1,078 99 1,086 1,110 1,440 Home  bedroom School/ Childcare 109 33 330 325 1,260 School or daycare facility Friend's/ Other's House 80 32 251 144 1,440 Friend's/ other's house  bedroom Stores, Restaurants, Shopping 24 35 69 50 475 Shopping mall Places In transit 69 83 83 60 1,111 Traveling in car Other Locations 79 57 139 105 1,440 Park, playground Don't Know/ Not Coded < 1 1 37 30 90

All Locations 1,440 Source: Wiley et al., 1991. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 32 August 1997 Table 15 15. Mean Time Children Spent in Six Location Categories Grouped by Age and Gender Location Category Mean Duration ( minutes/ day)

Boys Girls 0 2 yrs 3 5 yrs 6 8 yrs 9 11 yrs Boys 0 2 yrs 3 5 yrs 6 8 yrs 9 11 yrs Girls All All Home 1,157 1,134 1,044 1,020 1,094 1,151 1,099 1,021 968 1,061 School/ Childcare 86 88 144 120 108 59 102 133 149 111 Friend's/ Other's House 67 73 77 109 80 56 47 125 102 80 Stores, Restaurants, 21 25 22 15 21 23 35 27 26 28 Shopping Places In transit 54 62 61 62 59 76 88 53 93 79 Other Locations 54 58 92 114 77 73 68 81 102 81 Don't Know/ Not Coded < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 All Locations 1,439 1,440 1,439 1,440 1,439 1,438 1,440 1,440 1,440 1,440 a Sample Sizes 172 151 145 156 624 141 151 124 160 576 ( Unweighted)

The column totals may not sum to 1,440 due to rounding error. a Source: Wiley et al., 1991.

Table 15 16. Mean Time Children Spent in Six Location Categories Grouped by Season and Region Location Category Mean Duration ( minutes/ day)

Season Region of California Winter Spring Summer Fall All So. Bay Rest of All ( Jan Mar) ( Apr June) ( July Sept) ( Oct Dec) Seasons Coast Area State Regions Home 1,091 1,042 1,097 1,081 1,078 1,078 1,078 1,078 1,078 School/ Childcare 119 141 52 124 109 113 103 108 109 Friend's/ Other's House 69 75 108 69 80 73 86 86 80 Stores, Restaurants, 22 21 30 24 24 26 23 23 24 Shopping Places In transit 75 75 60 65 69 71 73 63 69 Other Locations 63 85 93 76 79 79 76 81 79 Don't Know/ Not Coded < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 All Locations 1,439 1,439 1,440 1,439 1,439 1,439 1,440 1,440 1,439 a Sample Sizes 318 204 407 271 1,200 224 263 713 1,200 ( Unweighted N's)

The column totals may not sum to 1,440 due to rounding error. a Source: Wiley et al., 1991. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 33 Table 15 17. Mean Time Children Spent in Proximity to Three Potential Exposures Grouped by All Respondents, Age, and Gender Potential Exposures Mean Duration ( minutes/ day)

Boys Girls All All All Children 0 2 yrs 3 5 yrs 6 8 yrs 9 11 yrs Boys 0 2 yrs 3 5 yrs 6 8 yrs 9 11 yrs Girls Tobacco Smoke 77 115 75 66 66 82 77 68 71 74 73 Gasoline Fumes 2 2 1 1 4 2 1 1 3 1 1 Gas Oven Fumes 11 10 15 12 11 12 12 10 10 7 10 Sample Sizes ( Unweighted N's) 1,166 168 148 144 150 610 140 147 122 147 556 a Respondents with missing data were excluded. a Source: Wiley et al., 1991.

Table 15 18. Range of Recommended Defaults for Dermal Exposure Factors Water Contact Soil Contact Bathing Swimming Central Upper Central Upper Central Upper Event time and 10 min/ event 15 min/ event 0.5 hr/ event 1.0 hr/ event 40 events/ yr 350 events/ yr frequency 1 event/ day 1 event/ day 1 event/ day 1 event/ day a 350 days/ yr 350 days/ yr 5 days/ yr 150 days/ yr Exposure 9 years 30 years 9 years 30 years 9 years 30 years duration Bathing event time is presented to be representative of baths as well as showers. a Source: U. S. EPA 1992. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 34 August 1997 Table 15 19. Number of Times Taking a Shower at Specified Daily Frequencies by the Number of Respondents TImes/ Day Total N 0 1 2 3 4 5 8 10 11: 1 0+ DK Overall 3594 2 2747 802 30 1 1 1 1 4 5 Gender Male 1720 * 1259 436 21 1 * * * 1 2 Female 1872 2 1486 366 9 * 1 1 1 3 3 Refused 2 * 2 * * * * * * * *

Age ( years) * 64 * 46 17 * * * * * * 1 1 4 41 * 30 9 1 * * * * * 1 5 11 140 * 112 26 1 * * * * * 1 12 17 270 * 199 65 6 * * * * * * 18 64 2650 1 1983 636 21 1 1 1 1 3 2 > 64 429 1 377 49 1 * * * * 1 *

Race White 2911 2 2323 562 17 * 1 * * 4 2 Black 349 * 199 140 7 1 * 1 * * 1 Asian 64 * 49 14 1 * * * * * * Some Others 65 * 40 23 2 * * * * * * Hispanic 162 * 103 56 2 * * * 1 * * Refused 43 * 33 7 1 * * * * * 2 Hispanic No 3269 2 2521 711 24 1 1 1 * 4 4 Yes 277 * 190 81 5 * * * 1 * * DK 17 * 13 4 * * * * * * * Refused 31 * 23 6 1 * * * * * 1 Employment * 439 * 330 99 8 * * * * * 2 Full Time 1838 1 1361 454 17 * * * 1 2 2 Part Time 328 1 261 65 * * 1 * * * * Not Employed 967 * 780 177 5 1 * 1 * 2 1 Refused 22 * 15 7 * * * * * * *

Education * 515 * 382 121 9 * * * * * 3 < High School 297 * 240 54 2 * * * * 1 * High School Graduate 1042 1 789 243 5 * 1 1 * 1 1 < College 772 1 589 176 4 * * * 1 * 1 College Graduate 576 * 434 133 7 1 * * * 1 * Post Graduate 392 * 313 75 3 * * * * 1 *

Census Region Northeast 828 * 622 196 7 * * * * * 3 Midwest 756 * 621 131 3 * * * * * 1 South 1246 1 893 334 14 1 * * * 3 * West 764 1 611 141 6 * 1 1 1 1 1 Day of Week Weekday 2481 * 1889 563 17 1 1 1 1 4 4 Weekend 1113 2 858 239 13 * * * * * 1 Season Winter 941 * 732 198 9 * * * * 1 1 Spring 889 * 674 205 7 * * * 1 * 2 Summer 1003 * 735 254 10 1 * * * 2 1 Fall 761 2 606 145 4 * 1 1 * 1 1 Asthma No 3312 2 2543 730 25 1 1 1 1 4 4 Yes 261 * 189 67 5 * * * * * * DK 21 * 15 5 * * * * * * 1 Angina No 3481 1 2653 786 29 1 1 1 1 4 4 Yes 91 1 77 12 1 * * * * * * DK 22 * 17 4 * * * * * * 1 Bronchitis/ Emphysema No 3419 2 2620 758 27 1 1 1 1 4 4 Yes 154 * 112 39 3 * * * * * * DK 21 * 15 5 * * * * * * 1 Note: * Signifies missing data; Dk= don't know; N = sample size. Source: Tsang and Klepeis, 1996 Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 35 Table 15 20. Times ( minutes) Spent Taking Showers by the Number of Respondents Total N Minutes/ Shower ** 0 10 10 20 20 30 30 40 40 50 50 60 60 61 Overall 3594 47 1640 1348 397 72 52 51 17 Gender Male 1720 13 788 625 213 35 25 14 7 Female 1872 34 850 693 184 37 27 37 10 Refused 2 * 2 * * * * * *

Age * 64 6 27 23 3 1 * 2 2 1 4 41 1 13 14 10 1 * 2 * 5 11 140 1 60 52 18 3 2 4 * 12 17 270 2 94 104 40 13 9 7 1 18 64 2650 16 1238 977 288 50 37 33 11 > 64 429 21 208 148 38 4 4 3 3 Race White 2911 38 1406 1070 292 39 31 26 9 Black 349 5 115 120 58 20 11 16 4 Asian 64 * 25 25 10 1 2 * 1 Some Others 65 * 18 29 6 3 4 4 1 Hispanic 162 1 57 60 25 8 4 5 2 Refused 43 3 19 14 6 1 * * *

Hispanic No 3269 43 1526 1188 352 61 42 44 13 Yes 277 1 98 109 40 10 8 7 4 DK 17 * 5 9 1 * 2 * * Refused 31 3 11 12 4 1 * * *

Employment * 439 4 163 165 66 17 10 12 2 Full Time 1838 10 875 682 191 32 20 20 8 Part Time 328 4 160 112 39 4 5 3 1 Not Employed 967 27 431 355 97 19 16 16 6 Refused 22 2 11 4 4 * 1 * *

Education * 515 10 190 186 79 21 13 14 2 < High School 297 8 93 125 51 6 7 6 1 High School Graduate 1042 12 451 409 108 23 17 16 6 < College 772 12 377 271 79 14 6 7 6 College Graduate 576 2 297 211 50 5 5 5 1 Post Graduate 392 3 232 116 30 3 4 3 1 Census Region Northeast 828 7 374 326 79 15 11 12 4 Midwest 756 11 385 253 70 16 9 9 3 South 1246 26 490 461 179 35 26 23 6 West 764 3 391 278 69 6 6 7 4 Day of Week Weekday 2481 34 1134 908 279 46 38 32 10 Weekend 1113 13 506 410 118 26 14 19 7 Season Winter 941 12 421 358 95 18 15 16 6 Spring 889 14 410 314 93 21 14 18 5 Summer 1003 11 435 366 128 29 17 12 5 Fall 761 10 374 280 81 4 6 5 1 Asthma No 3312 38 1526 1222 362 65 44 41 14 Yes 261 4 108 89 33 7 8 10 2 DK 21 5 6 7 2 * * * 1 Angina 3481 No 91 36 1591 1276 389 70 51 51 17 Yes 22 7 38 36 8 1 1 * * DK 4 11 6 * 1 * * *

Bronchitis/ Emphysema No 3419 40 1566 1258 375 67 47 50 16 Yes 154 3 66 54 19 5 5 1 1 DK 21 4 8 6 3 * * * *

NOTE: *  Missing data; DK = don't know; N = sample size; Refused = Refused to answer. A value of 61 for number of minutes signifies that more than 60 minutes were spent. Source: Tsang and Klepeis, 1996. Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 36 August 1997 Table 15 21. Number of Minutes Spent Taking a Shower ( minutes/ shower)

Category Population Group N Total Percentiles 1 2 5 10 25 50 75 91 95 98 99 100 Overall 3547 3 4 5 5 10 15 20 30 35 50 60 61 Gender Male 1707 3 4 5 5 10 15 20 30 30 45 60 61 Gender Female 1838 3 4 5 5 10 15 20 30 40 60 60 61 Age ( years) 1 4 40 5 5 5 5 5 10 17.5 30 50 60 60 60 Age ( years) 5 11 139 3 4 5 5 10 15 20 30 40 60 60 60 Age ( years) 12 17 268 5 5 5 7 10 15 25 35 45 60 60 61 Age ( years) 18 64 2634 3 3 5 5 10 15 20 30 30 45 60 61 Age ( years) > 64 408 3 3 5 5 10 10 20 30 30 45 60 61 Race White 2873 3 4 5 5 10 13 20 30 30 45 60 61 Race Black 344 4 4 5 6 10 20 30 40 60 60 61 61 Race Asian 64 1 3 4 5 10 15 20 30 40 48 61 61 Race Some Others 65 3 3 5 10 10 15 30 45 60 60 61 61 Race Hispanic 161 3 4 5 6 10 15 25 40 45 60 61 61 Hispanic No 3226 3 4 5 5 10 15 20 30 30 45 60 61 Hispanic Yes 276 3 4 5 6 10 15 22.5 39 45 60 61 61 Employment Full Time 1828 3 4 5 5 10 15 20 30 30 45 60 61 Employment Part Time 324 2 3 5 5 10 12 20 30 30 45 60 60 Employment Not Employed 940 3 3 5 5 10 15 20 30 40 60 60 61 Education < High School 289 4 5 5 8 10 15 20 30 40 60 60 61 Education High School Graduate 1030 2 3 5 5 10 15 20 30 40 60 60 61 Education < College 760 3 5 5 5 10 12 20 30 30 45 60 61 Education College Graduate 574 3 3 5 5 10 10 20 25 30 40 60 61 Education Post Graduate 389 2 3 4 5 7 10 15 25 30 45 60 61 Census Region Northeast 821 4 5 5 5 10 15 20 30 32 50 60 61 Census Region Midwest 745 3 4 5 5 10 10 20 30 30 45 60 61 Census Region South 1220 3 3 5 5 10 15 20 30 40 60 60 61 Census Region West 761 2 3 5 5 10 10 15 30 30 45 60 61 Day of Week Weekday 2447 3 4 5 5 10 15 20 30 35 48 60 61 Day of Week Weekend 1100 3 4 5 5 10 15 20 30 40 60 60 61 Season Winter 929 3 4 5 5 10 15 20 30 40 60 60 61 Season Spring 875 3 4 5 5 10 15 20 30 40 60 60 61 Season Summer 992 2 3 5 5 10 15 20 30 40 45 60 61 Season Fall 751 3 4 5 5 10 12 20 30 30 40 48 61 Asthma No 3274 3 4 5 5 10 15 20 30 32 45 60 61 Asthma Yes 257 3 4 5 5 10 15 20 40 50 60 60 61 Angina No 3445 3 4 5 5 10 15 20 30 35 50 60 61 Angina Yes 84 3 4 5 5 10 15 15 30 30 40 45 45 Bronchitis/ Emphysema No 3379 3 4 5 5 10 15 20 30 35 50 60 61 Bronchitis/ Emphysema Yes 151 3 4 5 5 10 15 20 30 40 48 60 61 NOTE: A value of 61 for number of minutes signifies that more than 60 minutes were spent. N = doer sample size. Percentiles are the percentage of doers below or equal to a given number of minutes. Source: Tsang and Klepeis, 1996. Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 37 Table 15 22. Time ( minutes) Spent in the Shower Room Immediately After Showering by the Number of Respondents Minutes/ Shower Total N ** 0 0 0 10 10 20 20 30 30 40 40 50 50 60 61 61 Overall 3594 61 241 2561 509 138 24 28 27 5 Gender Male 1720 22 113 1316 207 46 5 4 6 1 Female 1872 39 128 1243 302 92 19 24 21 4 Refused 2 * * 2 * * * * * *

Age ( years) * 64 6 9 37 7 3 * 1 1 * 1 4 41 * 5 31 3 1 * 1 * * 5 11 140 3 9 110 14 3 * * 1 * 12 17 270 1 17 206 29 10 3 2 1 1 18 64 2650 31 171 1897 388 99 19 18 23 4 > 64 429 20 30 280 68 22 2 6 1 *

Race White 2911 39 189 2074 430 110 20 23 21 5 Black 349 8 23 254 42 17 * 3 2 * Asian 64 * 7 45 9 2 * * 1 * Some Others 65 3 7 41 6 3 3 1 1 * Hispanic 162 6 11 118 19 4 1 1 2 * Refused 43 5 4 29 3 2 * * * *

Hispanic No 3269 48 216 2328 470 130 23 26 23 5 Yes 277 8 19 200 35 8 1 2 4 * DK 17 1 2 11 3 * * * * * Refused 31 4 4 22 1 * * * * *

Employment * 439 4 28 336 48 14 3 4 2 ?* Full Time 1838 20 109 1332 267 71 12 11 16 * Part Time 328 5 21 223 55 13 4 4 3 * Not Employed 967 29 81 655 138 39 5 9 6 5 Refused 22 3 2 15 1 1 * * * *

Education * 515 11 38 390 51 15 3 4 2 1 < High School 297 14 18 193 48 16 * 6 1 1 High School Graduate 1042 17 68 733 160 37 6 7 13 1 < College 772 11 56 536 118 33 7 4 5 2 College Graduate 576 3 28 426 86 19 8 3 3 * Post Graduate 392 5 33 283 46 18 * 4 3 *

Census Region Northeast 828 6 61 603 116 20 6 8 8 * Midwest 756 19 39 536 118 29 5 3 7 * South 1246 26 74 885 171 58 10 15 4 3 West 764 10 67 537 104 31 3 2 8 2 Day of Week Weekday 2481 43 165 1784 342 88 20 16 19 4 Weekend 1113 18 76 777 167 50 4 12 8 1 Season Winter 941 11 50 678 138 36 13 9 4 2 Spring 889 13 56 636 125 37 4 8 9 1 Summer 1003 25 92 691 138 39 5 5 7 1 Fall 761 12 43 556 108 26 2 6 7 1 Asthma No 3312 52 225 2374 465 123 19 24 26 4 Yes 261 2 14 178 42 15 5 3 1 1 DK 21 7 2 9 2 * * 1 * *

Angina No 3481 52 233 2495 486 132 24 27 27 5 Yes 91 3 5 55 22 5 * 1 * * DK 22 6 3 11 1 1 * * * *

Bronchitis/ Emphysema No 3419 53 226 2446 482 131 23 27 26 5 Yes 154 2 12 104 26 7 1 1 1 * DK 21 6 3 11 1 * * * * *

NOTE: * Signifies missing data. DK= respondents answered don't know. Refused = respondents refused to answer. N = doer sample size in specified range of number of minutes spent. A value of 61 for number of minutes signifies that more than 60 minutes were spent. Source: Tsang and Klepeis, 1996 Volume III  Activity Factors Chapter 15  Activity Factors Page Exposure Factors Handbook 15 38 August 1997 Table 15 23. Number of Minutes Spent in the Shower Room Immediately After Showering ( minutes/ shower)

Percentiles Category Population Group N 1 2 5 10 25 50 75 90 95 98 99 100 Overall 3533 0 0 0 1 3 5 10 20 30 40 50 61 Gender Male 1698 0 0 0 1 3 5 10 15 20 30 30 61 Gender Female 1833 0 0 0 1 3 5 12 20 30 45 60 61 Age ( years) 1 4 41 0 0 0 0 1 5 10 15 20 45 45 45 Age ( years) 5 11 137 0 0 0 1 2 5 10 15 20 30 30 60 Age ( years) 12 17 2619 0 0 0 1 3 5 10 20 30 40 52 61 Age ( years) 18 64 2619 0 0 0 1 3 5 10 20 30 40 52 61 Age ( years) > 64 409 0 0 0 1 4 5 10 20 30 35 45 60 Race White 2872 0 0 0 1 3 5 10 20 30 40 50 61 Race Black 341 0 0 0 1 3 5 10 20 25 30 45 60 Race Asian 64 0 0 0 0 2 5 10 15 20 30 60 60 Race Some Others 62 0 0 0 0 3 5 10 30 35 45 52 52 Race Hispanic 156 0 0 0 1 3 5 10 20 25 40 60 60 Hispanic No 3221 0 0 0 1 3 5 10 20 30 40 50 61 Hispanic Yes 269 0 0 0 1 3 5 10 20 25 45 60 60 Employment Full Time 1818 0 0 0 1 3 5 10 20 30 35 50 60 Employment Part Time 323 0 0 0 1 3 5 10 20 30 45 50 60 Employment Not Employed 938 0 0 0 1 3 5 10 20 30 45 60 61 Education < High School 283 0 0 0 1 3 5 15 20 30 45 45 61 Education High School Graduate 1025 0 0 0 1 3 5 10 20 30 45 60 61 Education < College 761 0 0 0 1 3 5 10 20 30 35 50 61 Education College Graduate 573 0 0 1 1 3 5 10 20 30 35 45 60 Education Post Graduate 387 0 0 0 1 2 5 10 20 30 30 45 60 Census Region Northeast 822 0 0 0 1 3 5 10 20 25 40 50 60 Census Region Midwest 737 0 0 0 1 3 5 10 20 30 35 45 60 Census Region South 1220 0 0 0 1 3 5 10 20 30 40 45 61 Census Region West 754 0 0 0 1 2 5 10 20 30 30 60 61 Day of Week Weekday 2438 0 0 0 1 3 5 10 20 30 40 50 61 Day of Week Weekend 1095 0 0 0 1 3 5 10 20 30 40 50 61 Season Winter 930 0 0 0 1 4 5 10 20 30 40 45 61 Season Spring 876 0 0 0 1 2 5 10 20 30 45 60 61 Season Summer 978 0 0 0 1 3 5 10 20 30 30 50 61 Season Fall 749 0 0 0 1 3 5 10 20 25 40 53 61 Asthma No 3260 0 0 0 1 3 5 10 20 30 38 50 61 Asthma Yes 259 0 0 0 1 3 5 13 20 30 40 45 61 Angina No 3429 0 0 0 1 3 5 10 20 30 40 50 61 Angina Yes 88 0 0 0 2 3 8.5 15 20 30 30 45 45 Bronchitis/ Emphysema No 3366 0 0 0 1 3 5 10 20 30 40 50 61 Bronchitis/ Emphysema Yes 152 0 0 0 1 2.5 5 10 20 30 30 45 60 NOTE: N = doer sample size. Percentiles are the percentage of doers below or equal to a given number of minutes. A value of 61 for number of minutes signifies that more than 60 minutes were spent. Source: Tsang and Klepeis, 1996 Volume III  Activity Factors Chapter 15  Activity Factors Exposure Factors Handbook Page August 1997 15 39 Table 15 24. Number of Baths Given or Taken in One Day by Number of Respondents Number of Baths/ Day Total N 1 2 3 4 5 6 7 10 11 15 DK Overall 649 459 144 20 9 4 2 1 1 1 3 5 Gender Male 159 117 33 5 1 * 1 1 * * 1 * Female 490 342 111 15 8 4 1 * 1 1 2 5 Age ( years) * 9 8 1 * * * * * * * * * 18 64 491 322 127 20 9 4 2 1 1 1 2 2 > 64 149 129 16 * * * * * * * 1 3 Race White 487 364 92 13 7 2 1 * * 1 2 5 Black 106 68 29 5 1 * 1 1 1 * * * Asian 12 5 5 * 1 * * * * * 1 * Some Others 12 7 4 1 * * * * * * * * Hispanic 26 10 13 1 * 2 * * * * * * Refused 6 5 1 * * * * * * * * * Hispanic No 600 430 127 19 9 2 2 1 1 1 3 5 Yes 40 21 16 1 * 2 * * * * * * DK 6 5 1 * * * * * * * * * Refused 3 3 * * * * * * * * * * Employment * 1 1 * * * * * * * * * * Full Time 283 183 76 12 5 * 2 1 1 1 1 1 Part Time 76 56 17 1 1 1 * * * * * * Not Employed 287 217 51 7 3 3 * * * * 2 4 Refused 2 2 * * * * * * * * * * Education * 4 4 * * * * * * * * * * < High School 96 66 19 3 2 2 * * * * 1 3 High School Graduate 235 167 54 8 2 * 1 1 * * * 2 < College 163 112 38 6 2 2 1 * * 1 1 * College Graduate 102 68 28 3 2 * * * 1 * * * Post Graduate 49 42 5 * 1 * * * * * 1 * Census Region Northeast 137 100 25 3 4 1 1 * * 1 * 2 Midwest 151 116 29 4 1 * * * 1 * * * South 255 164 70 9 2 3 1 1 * * 2 3 West 106 79 20 4 2 * * * * * 1 * Day of Week Weekday 415 299 89 10 4 2 2 1 1 1 2 4 Weekend 234 160 55 10 5 2 * * * * 1 1 Season Winter 178 124 37 10 1 3 * * * * 1 2 Spring 160 126 27 4 1 * * 1 * * * 1 Summer 174 112 49 4 3 1 1 * 1 * 2 1 Fall 137 97 31 2 4 * 1 * * 1 * 1 Asthma No 596 424 129 19 7 4 2 1 1 1 3 5 Yes 52 34 15 1 2 * * * * * * * DK 1 1 * * * * * * * * * * Angina No 620 435 141 19 9 4 2 1 1 1 3 4 Yes 26 22 2 1 * * * * * * * 1 DK 3 2 1 * * * * * * * * * Bronchitis/ Emphysema No 610 429 137 20 9 4 2 1 1 1 2 4 Yes 36 27 7 * * * * * * * 1 1 DK 3 3 * * * * * * * * * *