Tables 5.4 and 5.5 give the impactor results for the summer and winter, respectively. The mass collected by the impactor is listed in column 3. The corresponding PM 10 mass collected on Teflo filters is given for comparison. The impactor samples were drawn directly from the dilution tunnel; i. e., a PM 10 cyclone was not used. Therefore, it is possible for the impactors to collect more mass than the filter samples that were collected after the PM 10 cyclone. To facilitate the mass comparison, any mass collected on the first stage, which has a cutoff of 21.9 µ m, was deleted from the total mass reported in the Tables. On the other hand, some losses of particles within impactors is considered unavoidable. Also, since the last five stages operate at reduced pressure, some semivolatile material may be lost. Thus, it is common to have the sum of the mass collected by impactors to be less than the mass collected on filters. The average ratio of impactor mass 60 to filter mass for the gasoline vehicles was 0.82 in the summer and 0.89 in the winter. The average ratio was higher for the winter smoking vehicles, 0.99, but lower for the diesels 0.80. Overall, the agreement between the impactor and filter mass is considered acceptable.

Plots of cumulative mass percentage versus the log of the particle size were prepared for each sample. Interpolation between points was used to determine the mass median diameter ( MMD) of each sample and the percent of mass with a particle size less than 2.5 µ m. These are listed in the last two columns of Tables 5.4 and 5.5. Gasoline vehicles had the lowest average MMD, 0.12 µ m in the winter and 0.15 µ m in the summer. The summer value drops to 0.12 µ m if the distribution with a MMD of 0.32 is eliminated. Smoking vehicles and diesels had the same average MMD, 0.18 µ m. The diesel MMD is similar to that reported by others using EAA measurements ( Groblicki and Begeman, 1979), but lower than the 0.3 µ m diameter reported by Chan and Lawson ( 1981), who used coated impaction stages in cascade impactors. Smaller MMDs have been reported for catalyst equipped vehicles. For example, Groblicki ( 1976) reported MMDs of 0.02 to 0.03 µ m for oxidation catalyst vehicles equipped with air pumps. The PM from these vehicles was dominated by sulfate. That was not the case for the vehicles in this study.

The fraction of the mass contained in particles smaller than 2.5 µ m is relevant to the new PM NAAQS. Tables 5.4 and 5.5 show that on average 92 and 91 percent of the mass from gasoline vehicles was smaller than 2.5 µ m. For smoking and diesel vehicles the percent less than 2.5 µ m increased to an average of 97 and 98%, respectively. These results can be compared to those reviewed by Energy and Environmental Analysis, Inc. ( 1985). They reported that the PM mass exhaust emissions from light duty vehicles operated on unleaded fuel had an average of 89% of the mass smaller than 2.0 µ m, while diesels had 90% of the mass smaller than 2.0 µ m. Durbin et al. ( 1998) measured particle size distributions from smoking gasoline and diesel vehicles. They found that, on average, 91.8% of the mass was smaller than 2.5 µ m.

Table 5.4. Summer Impactor Results Run No. Vehicle Type Impactor Total Mass, mg Filter Total Mass, mg Mass Ratio Impactor/ Filter MMD, µ m Fraction < 2.5 µ m 4545 G 6.23 8.89 0.70 0.18 0.97 4576 G 3.19 NA NA 0.13 0.98 4560 G 2.40 2.77 0.87 0.13 0.97 4527 G 2.35 3.04 0.77 0.12 0.93 4542 G 0.31 0.26 1.19 0.08 0.91 4533/ 35 G 0.27 0.47 0.58 0.12 0.86 4523 G 0.16 NA NA 0.32 0.82 average 0.82 0.15 0.92 61 Table 5.5. Winter Impactor Results Run No. Vehicle Type Impactor Total Mass, mg Filter Total Mass, mg Mass Ratio Impactor/ Filter MMD, µ m Fraction < 2.5 µ m 4907 D 8.89 13.75 0.65 0.21 0.99 4929 D 6.34 6.23 1.02 0.16 0.99 4894 D 6.08 7.32 0.83 0.21 0.99 4910 D 5.56 7.22 0.77 0.21 0.99 4897 D 3.92 5.40 0.73 0.21 0.90 4926 D 1.87 2.39 0.78 0.11 0.98 4891 D 1.03 NA NA 0.14 0.99 average 0.80 0.18 0.98 4809 S 10.64 9.80 1.09 0.20 0.99 4695 S 5.71 5.08 1.12 0.17 0.89 4847 S 5.07 NA NA 0.17 0.99 4748 S 4.47 4.64 0.96 0.18 0.97 4816 S 4.09 4.76 0.86 0.17 0.99 4758 S 3.79 4.20 0.90 0.21 0.99 4819 S 2.33 2.35 0.99 0.18 0.98 average 0.99 0.18 0.97 4873 G 2.18 2.67 0.82 0.13 0.93 4879 G 1.80 2.10 0.86 0.17 0.92 4882 G 1.22 1.75 0.70 0.10 0.97 4711 G 1.10 1.01 1.09 0.11 0.87 4837 G 1.02 1.22 0.84 0.12 0.96 4763 G 0.97 1.06 0.91 0.12 0.90 4701 G 0.96 0.89 1.08 0.11 0.77 4794 G 0.92 1.03 0.89 0.12 0.90 4860 G 0.53 0.46 1.15 0.07 0.92 4797 G 0.50 0.73 0.69 0.12 0.97 4885 G 0.27 0.37 0.72 0.07 0.95 4863 G 0.17 0.04 4.64 0.17 0.91 average 0.891 0.12 0.91 1) Run 4863 omitted from average 62 63 64 65 66 67 68 69 6. Chemical Composition of the Particulate Matter Carbon. The bulk of the PM mass is expected to be carbonaceous material. The TOR carbon analysis separates that material into " organic" ( OC) and " elemental" carbon ( EC). This separation is important for multiple reasons. First, EC absorbs light efficiently, and thus has a much greater impact on visibility reduction in the atmosphere than organic carbon. Second, tracer compounds such as the PAHs discussed later are associated with the organic carbon fraction. It may be instructive to examine their composition in terms of their fraction of the organic matter rather than the total PM. Third, these same measurements are made on atmospheric PM samples. Therefore, the OC/ EC split may provide some information for source apportionment. Finally, the fraction of OC may qualitatively provide information as to the impact of oil consumption on vehicular PM emissions. It may be possible to refine the estimate regarding oil consumption further by examining the temperature at which the OC evolves in the analytical procedure.

For the summer portion of the study, OC and EC were measured for each FTP phase from 38 vehicles, six 1971 80, seven 1981 85, eleven 1986 90, four 1991 96, six smokers, and four diesels. The first step in analyzing the data was to determine what fraction of the total mass is accounted for by the carbon. Figure 6.1 shows the comparison between total carbon and mass for all vehicles. The plot includes points representing each phase of the FTP. The regression line has a slope of 0.97, and an R2 of 0.71. The near equivalence between total carbon and mass indicates a problem in the data. Carbon can not constitute all the mass, since carbonaceous material includes other elements such as hydrogen, oxygen, nitrogen, and sulfur, and some non carbonaceous material is present as well. In fact, it is generally assumed that the organic carbon measurement for a source sample should be multiplied by a factor of 1.2 to account for the other. Inspection of Figure 6.1 shows a set of points that have much higher carbon mass than total mass which are significantly influencing the regression. Since most of these points have a relatively high mass, it was decided to examine the mass vs. total carbon relationship separately for the non smoking gasoline vehicles, the smokers, and the diesels. The results are shown in Figures 6.2 6.4. The linear regression for the non smoking gasoline vehicles ( Figure 6.2  one very high mass emission rate point removed) has a slope of 0.77 and an R2 of 0.87. It is shown below that approximately 80% of the total carbon from the summer samples is organic material. Multiplying this fraction of the total carbon by the 1.2 factor, shows that carbonaceous material is 89% of the total mass. This relationship was examined for each phase of the FTP for the non smoking vehicles as well. The slopes of the linear regressions for phases 1 3, respectively, were 0.79, 0.66, and 0.80, while the R2 values were 0.84, 0.87 and 0.87. Figure 6.3 shows the results for the smoking vehicles. The average values are much higher than for the non smoking vehicles, and there is a suggestion that there are two sets of points, one set with a relatively good agreement between carbon and mass, and one where the total carbon is much higher than the total mass. The diesels, Figure 6.4, have consistently higher total carbon than mass.

Figure 6.5 shows the relationship between total carbon and PM 10 mass for the winter non smoking gasoline vehicles. The slope of 0.76 is similar to that obtained for the summer samples while the R2 of 0.995 is better ( the R2 was 0.81 before one outlier was 70 removed). The same relationship for the smoking vehicles had a slope of 0.78 and an R2 of 0.99 with the two highest emission rate points removed. Inclusion of the two points gave a slope of 0.53 with an R2 of 0.98. The diesel vehicles had a slope of 0.45 and an R2 of 0.63. There was considerable scatter in the highest emission rate values. Considering only those emission rates below 1000 mg/ mi resulted in a slope of 0.58 and an R2 of 0.89. If the regression was forced through zero, the slope increased to 0.71 with an R2 of 0.84. Overall, the winter data are consistent, indicating that most of the PM 10 mass is carbonaceous material.

The cause of the poor agreement between total carbon and PM 10 mass for the summer diesel samples and some of the summer smoking vehicle samples has not been found. Possible explanations include inhomogeneous filter deposits for some heavily loaded samples or undetected leaks for some heavily loaded PM 10 filters. The former explanation is not a concern, since the main purpose of the carbon analysis was to provide the ratio of OC and EC. Inhomogeneous deposits should not affect this measurement. Possible leaks associated with the measurement of PM 10 mass are of concern. However, there is no other indication that these occurred.

The split between OC and EC for each sample was examined as well. Results are given in Table 6.1 for the summer samples and Table 6.2 for the winter samples. The samples have been grouped by vehicle type ( gasoline, smokers and diesel). For source apportionment purposes, DRI will group gasoline vehicles together based on their PM emission rates, rather than their model year. The emission rate categories used are low ( L), medium low ( ML), medium ( M) and high ( H). The third column of Tables 6.1 and 6.2 ( ID) indicates the source apportionment grouping, with the number referring to the corresponding pooled sample for PAH. D and S refer to diesel and smoker, respectively. Thus, an ID of H2 indicates that the vehicle is used in the second pooled high gasoline PM emitter sample. The split between OC and EC for FTP phase 1 summer samples is presented graphically in Figure 6.6. The solid bar is the percent EC. Non smoking gasoline vehicles are indicated by the open OC bar, the smoking gasoline vehicles with the horizontal stripped OC bar, and the diesels with the diagonal stripped OC bar. Within these categories the vehicles are arranged in order of increasing FTP emissions from left to right. There is clearly a trend towards a higher OC fraction with increasing emission rate for the gasoline vehicles. The smoking gasoline vehicles have relatively high OC fractions, with the two highest emitters having more than 96% of the carbon as " organic" material. The diesels, on the other hand, have relatively low OC fractions. Figure 6.7 shows similar trends for the winter FTP phase 1 samples. Unlike the summer samples, two of the highest gasoline PM 10 emitters have relatively high EC fractions. Figures 6.8 and 6.9 plot the data for summer FTP phases 2 and 3. The phase 2 OC fraction is higher than that of phase 1 for many of the vehicles. Results were similar for the winter. The FTP phase difference in OC fraction is summarized in Figure 6.10, which gives the average OC 71 fraction for each of the vehicle categories by FTP phase. The 1981 85, 1986 90, 1991 96, and diesel vehicles clearly have lower average percent OC in phase 1 than phase 2. This is not the case for the older gasoline vehicles and the smoking gasoline vehicles.

The TOR carbon analysis method measures the OC evolved sequentially at four temperatures; 120, 250, 450, and 550 ° C. The percentage of the total OC evolved at each of these temperatures was determined for each FTP phase for all of the winter samples. Volatilization of organic carbon under conditions that have been shown to remove motor oil has been used to estimate the contribution of motor oil to the PM mass. While motor oil has not been characterized using TOR, differences in the percent OC removed at a given temperature between vehicles might indicate a difference in the motor oil contribution. Consistent differences between vehicle types could also be used to strengthen the differences in profiles for source apportionment. Figures 6.11 6.13 give the results. Vehicles are arranged in the same order as in Figure 6.7. G, S, and D on the xaxis stand for gasoline, smoker, and diesel vehicles, respectively ( there are 8 smokers and 11 diesels). For FTP phase 1 ( Figure 6.11), more than 50% of the OC is removed at 250 ° C for all the vehicles. Better than 90% of the OC is removed at 250 ° C for the vehicles identified as smokers. In contrast, approximately 80% of the OC is removed at 250 ° C for the diesels. For FTP phase 2 ( Figure 6.12), the gasoline vehicles tend to have a higher percentage of the OC removed by 250 ° C . Phase 3 ( Figure 6.13) is similar to phase 1. The large vehicle to vehicle variability suggests that the OC removal temperature will not be very useful in distinguishing between these three source types. The results also suggest that motor oil could be a significant contributor to the OC fraction of the PM for all the vehicles.

Sulfate and nitrate emission rates. Table 6.3 gives individual and average FTP sulfate and nitrate emission rates by vehicle category for the summer study. Minimum detection limits for nitrate and sulfate were approximately 0.04 mg/ mi. Only 21 of 117 filter extracts had nitrate concentrations in excess of the measurement uncertainty. In contrast, 101 of the 117 filter extracts had sulfate concentrations greater than the measurement uncertainty. Only one vehicle, a 1989 diesel, had an FTP nitrate emission rate in excess of 1 mg/ mi. The highest nitrate FTP emission rate for a gasoline vehicle was 0.17 mg/ mi. Sulfate FTP emission rates were also generally low, with only one gasoline vehicle having an emission rate in excess of 1 mg/ mi. In contrast, all four diesel vehicles tested had sulfate emission rates of 1 mg/ mi or higher. The 1989 diesel vehicle with significant nitrate emissions also had high sulfate emissions ( 17.8 mg/ mi). Sulfate emissions for this vehicle were high in both phases 1 and 3, whereas nitrate was high only in phase 1. FTP results for the winter study are given in Table 6.4. No nitrate emission rates are reported for the smokers or the diesels because the filters used for these vehicles had a high nitrate background. For the gasoline vehicles, nitrate emission rates were very low, averaging less than 0.1 mg/ mi. The highest nitrate emission rate was 0.26 mg/ mi. Overall, it is concluded that nitrate is not a significant contributor to PM emissions. The gasoline vehicle winter sulfate emission rate averaged less than 0.6 mg/ mi for each vehicle category, with only two vehicles having an emission rate greater than 1.0 mg/ mi. The smokers had higher sulfate emission rates in the winter than summer, with 5 of the 8 vehicles exceeding 1.0 mg/ mi. Diesels also had higher sulfate emission rates than the gasoline vehicles, averaging 2.74 72 mg/ mi.

Table 6.1. OC and EC Percentages by FTP Phase for Each Summer Vehicle Vehicle Run MY ID1 Ph1 % OC Ph1 % EC Ph2 % OC PH2 % EC PH3 % OC Ph3 % EC FTP PM, mg/ mi 1971 80 4510 1975 H3 88.10 11.88 96.30 3.69 83.08 16.96 110.9 1971 80 4506 1976 H1 90.83 9.17 96.84 3.23 81.30 18.70 47.9 1971 80 4551 1976 90.86 9.14 72.82 27.18 74.84 25.26 254.6 1971 80 96078 1976 76.75 23.25 92.54 7.46 81.57 18.51 21.2 1971 80 4538 1978 86.29 13.71 90.54 9.46 86.84 13.21 56.1 1971 80 96105 1978 74.61 25.39 81.33 18.67 92.53 7.48 122.4 Mean 82.13 17.87 84.31 15.69 83.95 16.11 113.56 Std dev 6.69 6.69 7.86 7.86 6.53 6.56 89.16 1981 85 96047 1981 M3 63.49 36.51 60.32 39.68 48.46 51.54 21.8 1981 85 96081 1981 47.40 52.60 91.87 8.47 78.79 20.94 3.2 1981 85 96074 1983 H1 48.88 51.12 43.90 56.10 45.89 54.24 42.9 1981 85 96186 1983 H2 94.41 5.59 94.86 5.20 93.44 6.56 68.9 1981 85 96090 1983 M3 48.71 51.29 77.16 23.09 49.27 50.73 32.6 1981 85 4479 1984 M1 92.10 7.94 90.94 9.17 81.63 18.49 28.3 1981 85 4560 1985 H3 89.65 10.36 79.74 20.26 81.24 18.76 99.8 Mean 81.22 18.80 85.67 14.43 76.39 23.64 57.39 Std dev 18.85 18.84 7.41 7.45 16.41 16.40 29.11 1986 90 4482 1986 M1 38.79 61.27 89.68 10.32 48.16 51.84 16.4 1986 90 4490 1986 M2 95.41 4.59 85.58 14.42 85.58 14.17 13.2 1986 90 96010 1986 27.84 72.16 71.47 25.84 0.00 109.86 1.3 1986 90 96164 1986 87.16 12.84 95.19 4.81 85.88 14.12 766.3 1986 90 96071 1987 L2 58.82 41.03 91.42 8.46 75.01 24.73 6.4 1986 90 96065 1987 M2 41.49 58.51 59.07 40.93 42.70 57.30 27.8 1986 90 96068 1988 L1 57.83 41.90 93.88 6.12 48.17 51.83 2.1 1986 90 96183 1989 H2 76.24 23.76 76.88 23.19 70.33 29.67 52.5 1986 90 96180 1989 93.53 6.47 95.29 4.71 92.29 7.71 38.9 1986 90 96044 1990 L3 65.98 34.02 94.32 5.46 66.66 33.34 9.7 1986 90 96102 1990 L3 73.30 26.75 90.20 9.80 57.13 42.70 9.2 Mean 77.26 22.75 89.17 10.79 71.60 28.36 27.58 Std dev 10.11 10.11 7.35 7.42 12.88 12.83 18.75 1991 96 96143 1991 L1 69.78 30.41 87.54 12.28 87.69 12.13 1.8 1991 96 4554 1992 L2 43.89 56.11 58.30 41.70 63.21 37.22 7.3 1991 96 4487 1992 49.30 50.70 82.80 17.20 51.34 45.40 0.9 1991 96 4524 1994 L1 69.37 30.80 69.54 30.46 90.02 11.23 2.2 Mean 58.09 42.01 74.54 25.41 73.07 26.50 3.04 Std dev 11.65 11.56 11.47 11.52 16.36 15.10 2.51 Smoker 96062 1986 S1 97.62 2.38 99.18 0.82 97.27 2.74 442.5 Smoker 96201 1988 S1 96.85 3.15 99.53 0.47 97.29 2.71 551.5 Smoker 96189 1983 S2 92.07 7.93 60.98 39.01 89.03 10.97 180.6 Smoker 96192 1984 S2 77.07 22.93 86.09 13.90 37.73 62.27 144.3 Smoker 4502 1971 S3 93.29 6.71 92.71 7.31 95.15 4.85 94.0 Smoker 96161 1966 S3 83.53 16.48 89.11 10.85 79.44 20.58 277.4 Mean 86.49 13.51 82.22 17.77 75.34 24.67 174.10 Std dev 6.61 6.61 12.49 12.49 22.42 22.42 67.09 Diesel 4593 1993 D1 29.67 70.33 45.18 54.80 20.65 79.37 282.4 Diesel 4605 1995 D1 33.76 66.24 66.79 33.25 55.03 44.99 143.3 Diesel 4595 1994 D2 41.04 58.96 55.96 44.04 43.62 56.38 288.7 Diesel 4589 1989 D3 67.60 32.40 66.79 33.21 57.80 42.20 3988.2 Mean 43.02 56.98 58.68 41.33 44.28 55.74 1175.63 Std dev 14.77 14.76 8.96 8.94 14.64 14.64 1624.87 1) L, M, H, S, D refer to low, medium, high PM emitters, smoker, and diesel. The associated number is a sample id.

Table 6.2. OC and EC Percentages by FTP Phase for Each Winter Vehicle 73 Vehicle Run MY ID1 Ph1 % OC Ph1 % EC Ph2 % OC Ph2 % EC Ph3 % OC Ph3 % EC FTP PM, mg/ mi 1971 80 97056 1971 H1 43.2 56.8 87.7 12.3 42.0 58.0 276.0 1971 80 97053 1975 M1 71.7 28.3 78.0 22.0 48.6 51.4 103.0 1971 80 97158 1978 H2 66.3 33.7 33.6 66.4 54.1 45.9 124.0 1971 80 97161 1978 ML2 58.9 41.1 66.9 33.1 72.5 27.5 31.3 1971 80 97013 1979 M1 82.3 17.7 96.6 3.4 97.4 2.6 61.6 1971 80 97096 1980 M3 64.0 36.0 64.8 35.2 80.1 19.9 56.9 Mean 64.4 35.6 71.3 28.7 65.8 34.2 108.8 Std dev 13.1 13.1 22.1 22.1 21.2 21.2 88.5 1981 85 97165 1981 M3 69.0 31.0 93.5 6.5 93.8 6.2 41.9 1981 85 97025 1983 H1 10.2 89.8 23.2 76.8 26.7 73.3 152.0 1981 85 97062 1984 ML1 51.3 48.7 70.5 29.5 51.5 48.5 40.3 1981 85 97115 1984 ML1 40.0 60.0 74.3 25.7 37.0 63.0 21.6 1981 85 97112 1984 M2 38.5 61.5 65.3 34.8 21.3 78.7 55.1 1981 85 97059 1985 M2 35.6 64.4 74.2 25.8 50.6 49.4 54.1 Mean 40.7 59.3 66.8 33.2 46.8 53.2 60.8 Std dev 19.4 19.4 23.4 23.4 26.1 26.1 46.3 1986 90 97072 1986 L1 74.0 26.0 79.0 21.0 67.1 32.9 9.3 1986 90 97044 1987 L2 39.1 60.9 83.3 16.7 42.3 57.7 8.1 1986 90 97016 1989 L1 69.2 30.8 92.9 7.1 75.0 25.0 9.7 1986 90 97047 1989 M1 77.8 22.2 92.9 7.1 90.7 9.3 73.9 1986 90 97099 1990 ML1 48.0 52.0 51.0 49.0 29.6 70.4 44.0 1986 90 97137 1990 L2 41.3 58.7 79.6 20.4 70.0 30.0 5.2 Mean 58.2 41.8 79.8 20.2 62.5 37.5 25.0 Std dev 17.4 17.4 15.4 15.4 22.5 22.5 28.0 1991 96 97168 1991 L2 70.6 29.4 90.0 10.0 91.7 8.3 8.2 1991 96 97075 1993 ML2 26.2 73.8 55.0 45.0 72.7 27.3 10.8 1991 96 97134 1993 M3 58.0 42.0 64.8 35.2 44.6 55.4 51.3 1991 96 97127 1993 L1 49.7 50.3 83.0 17.0 75.0 25.0 6.3 1991 96 97109 1994 H2 92.0 8.0 97.6 2.4 76.5 23.5 123.0 Mean 59.3 40.7 78.1 21.9 72.1 27.9 39.9 Std dev 24.4 24.4 17.7 17.7 17.1 17.1 50.0 Smoker 97093 1971 S1 55.7 44.3 67.8 32.2 70.0 30.0 1350.0 Smoker 97146 1975 S3 94.1 5.9 96.4 3.6 96.2 3.8 179.0 Smoker 97050 1976 S1 74.5 25.5 69.6 30.4 47.7 52.3 836.0 Smoker 97081 1977 S2 83.3 16.7 87.6 12.4 82.4 17.6 214.0 Smoker 97103 1981 S2 85.7 14.3 96.6 3.4 94.1 5.9 887.0 Smoker 97084 1983 S3 86.9 13.1 98.0 2.0 95.5 4.5 185.0 Smoker 97152 1985 S3 82.9 17.1 92.0 8.0 88.2 11.8 238.0 Smoker 97087 1989 S2 94.1 5.9 98.6 1.4 93.7 6.3 704.0 Mean 82.2 17.8 88.3 11.7 83.5 16.5 574.1 Std dev 12.4 12.4 12.7 12.7 16.9 16.9 436.8 Diesel 97251 1979 D1 44.2 55.8 31.2 68.8 55.6 44.4 933.0 Diesel 97242 1979 D1 45.0 55.0 60.6 39.4 45.2 54.8 763.0 Diesel 97245 1979 D4 21.9 78.1 14.4 85.6 14.4 85.6 485.0 Diesel 97248 1980 D3 25.5 74.5 14.6 85.4 23.1 76.9 462.0 Diesel 97233 1981 D4 13.3 86.7 16.0 84.0 16.9 83.1 371.0 Diesel 97239 1981 D5 13.2 86.8 18.2 81.8 16.9 83.1 194.0 Diesel 97267 1982 D3 64.9 35.1 16.4 83.6 17.1 82.9 607.0 Diesel 97254 1982 D2 57.6 42.4 69.2 30.8 68.1 31.9 504.0 Diesel 97257 1982 D5 58.5 41.5 80.0 20.0 73.6 26.4 539.0 Diesel 97270 1983 D2 15.1 84.9 16.8 83.2 15.1 84.9 749.0 Diesel 97261 1984 D5 44.8 55.2 37.8 62.2 35.4 64.6 306.0 mean 36.7 63.3 34.1 65.9 34.7 65.3 537.5 Std dev 19.5 19.5 24.6 24.6 22.5 22.5 215.8 1) L, M, H, S, D refer to low, medium, high PM emitters, smoker, and diesel. The associated number is a sample id.

Table 6.3. Summer Sulfate and Nitrate FTP Emission Rates Vehicle RUN # MY ID NO3 SO4 mg/ mi mg/ mi 1971 80 4510 1975 H3 0.060 0.382 1971 80 4506 1976 H1 0.050 0.100 1971 80 4551 1976 0.170 8.693 1971 80 96078 1976 0.041 0.348 1971 80 4538 1978 0.044 0.262 1971 80 96105 1978 0.159 0.207 74 mean 0.087 1.665 min 0.041 0.100 max 0.170 8.693 1981 85 96047 1981 M3 0.000 0.068 1981 85 96081 1981 0.000 0.038 1981 85 96074 1983 H1 0.041 0.144 1981 85 96186 1983 H2 0.000 0.121 1981 85 96090 1983 M3 0.027 0.206 1981 85 4479 1984 M1 0.000 0.172 1981 85 4560 1985 H3 0.000 0.139 mean 0.010 0.127 min 0.000 0.038 max 0.041 0.206 1986 90 4482 1986 M1 0.000 0.192 1986 90 4490 1986 M2 0.000 0.050 1986 90 96010 1986 0.000 0.022 1986 90 96164 1986 0.119 0.483 1986 90 96071 1987 L2 0.000 0.108 1986 90 96065 1987 M2 0.000 0.041 1986 90 96068 1988 L1 0.000 0.072 1986 90 96183 1989 H2 0.054 0.141 1986 90 96180 1989 0.000 0.330 1986 90 96044 1990 L3 0.000 0.120 1986 90 96102 1990 L3 0.000 0.095 mean 0.016 0.150 min 0.000 0.022 max 0.119 0.483 1991 96 96143 1991 L1 0.000 0.052 1991 96 4554 1992 L2 0.000 0.101 1991 96 4487 1992 0.000 0.003 1991 96 4524 1994 L1 0.000 0.046 mean 0.000 0.051 min 0.000 0.003 max 0.000 0.101 Smoker 96062 1986 S1 0.000 0.751 Smoker 96201 1988 S1 0.000 0.505 Smoker 96189 1983 S2 0.000 0.091 Smoker 96192 1984 S2 0.051 0.322 Smoker 96161 1966 S3 0.066 0.180 Smoker 4502 1971 S3 0.138 0.209 mean 0.043 0.343 min 0.000 0.091 max 0.138 0.751 Diesel 4593 1993 D1 0.084 1.057 Diesel 4605 1995 D1 0.064 1.449 Diesel 4595 1994 D2 0.597 2.124 Diesel 4589 1989 D3 4.311 17.790 mean 1.264 5.605 min 0.064 1.057 max 4.311 17.790 75 Table 6.4. Winter Sulfate and Nitrate FTP Emission Rates Vehicle Run # MY ID NO3 mg/ mi SO4 mg/ mi 1971 80 97056 1971 H1 0.263 1.550 1971 80 97053 1975 M1 0.071 0.421 1971 80 97161 1978 ML2 0.060 0.372 1971 80 97158 1978 H2 0.044 0.474 1971 80 97013 1979 M1 0.051 0.110 1971 80 97096 1980 M3 0.048 0.372 mean 0.090 0.550 min 0.044 0.110 max 0.263 1.550 1981 85 97165 1981 M3 0.050 0.139 1981 85 97025 1983 H1 0.188 0.048 1981 85 97112 1984 M2 0.073 0.901 1981 85 97115 1984 ML1 0.045 0.350 1981 85 97062 1984 ML1 0.064 1.272 1981 85 97059 1985 M2 0.078 0.866 mean 0.083 0.596 min 0.045 0.048 max 0.188 1.272 1986 90 97072 1986 L1 0.062 0.196 1986 90 97044 1987 L2 0.038 0.106 1986 90 97047 1989 M1 0.056 0.123 1986 90 97016 1989 L1 0.041 0.141 1986 90 97137 1990 L2 0.029 0.157 1986 90 97099 1990 ML1 0.033 0.933 mean 0.043 0.276 min 0.029 0.106 max 0.062 0.933 1991 96 97168 1991 L2 0.044 0.281 1991 96 97134 1993 M3 0.074 0.493 1991 96 97127 1993 L1 0.018 0.055 1991 96 97075 1993 ML2 0.032 0.205 1991 96 97109 1994 H2 0.055 0.489 mean 0.045 0.305 min 0.018 0.055 max 0.074 0.493 Smoker 97093 1971 S1 ND 7.027 Smoker 97146 1975 S3 ND 0.443 Smoker 97050 1976 S1 ND 2.535 Smoker 97081 1977 S2 ND 0.589 Smoker 97103 1981 S2 ND 1.185 Smoker 97084 1983 S3 ND 1.038 Smoker 97152 1985 S3 ND 0.261 Smoker 97087 1989 S2 ND 1.326 mean ND 1.801 min ND 0.261 max ND 7.027 Diesel 97251 1979 D1 ND 3.508 Diesel 97245 1979 D4 ND 3.550 Diesel 97242 1979 D1 ND 5.220 Diesel 97248 1980 D3 ND 4.170 Diesel 97239 1981 D5 ND 1.208 Diesel 97233 1981 D4 ND 1.985 Diesel 97267 1982 D3 ND 1.938 Diesel 97257 1982 D5 ND 1.560 Diesel 97254 1982 D2 ND 3.036 Diesel 97270 1983 D2 ND 3.238 Diesel 97261 1984 D5 ND 0.760 mean ND 2.743 min ND 0.760 max ND 5.220 Since the number of cold and hot starts may be different in real world operation from the weighting factors used for the FTP, it is useful to examine the emission rates by FTP phase. Table 6.5 gives the average sulfate emission rates for each vehicle category by FTP 76 phase. Emissions are highest in phase 1 ( cold start operation) and lowest in phase 2 ( hot stabilized operation) during both the summer and winter.

It is commonly assumed that sulfate emitted from vehicles is present as sulfuric acid. Sulfuric acid is very hygroscopic. It is also frequently assumed that each sulfate ion has seven water molecules associated with it under the standard temperature and humidity conditions used in weighting rooms. Accounting for the water would raise the mass contribution to the measured PM by a factor of 2.3; i. e., 1 mg/ mi sulfate would give rise to 2.3 mg/ mi PM mass. For low PM emission rate vehicles, the sulfate and associated water could be a significant fraction of the total PM emission. Since acidity measurements were not made, it is not know how much, if any, of the sulfate in this study was present as sulfuric acid. Overall, it does not appear that sulfate and associated water are significant contributors to the PM emission rate for the in use gasoline fleet.

Table 6.5. Average Sulfate Emission Rates for Each FTP Phase Category Period Phase 1 mg/ mi Phase 2 mg/ mi Phase 3 mg/ mi 1971 80 Summer 7.51 ( 0.69) 1 0.13 0.20 1981 85 Summer 0.27 0.08 0.11 1986 90 Summer 0.28 0.15 0.24 1991 96 Summer 0.08 0.05 0.03 Smokers Summer 0.33 0.20 0.34 Diesels Summer 9.19 ( 3.76) 1 2.31 ( 0.81) 1 9.16 ( 1.28) 1 1971 80 Winter 1.57 0.26 0.35 1981 85 Winter 0.91 0.29 0.94 1986 90 Winter 0.45 0.17 0.35 1991 96 Winter 0.83 0.12 0.29 Smokers Winter 6.03 ( 2.24) 1 0.61 0.94 Diesels Winter 7.51 1.37 1.76 1) Values in ( ) are the averages with the highest emission rate removed The IC sulfate measurements can be compared to the total sulfur XRF measurements. Figure 6.14 plots XRF sulfur versus IC sulfur for all vehicles in the summer, where the IC results have been adjusted to remove the mass of the associated oxygen. This figure plots data from each of the three FTP phases rather than the composite FTP data. The linear regression had a slope of 0.35 and an R2 of 0.74. The average ratio of IC sulfur to XRF sulfur for the summer was 0.40, 0.50, and 0.45 for FTP phases 1 3, respectively. For the winter, the correlation between IC sulfur and XRF sulfur was stronger, having a slope of 0.39 and an R2 of 0.92 for all vehicles and all FTP phases. For gasoline and smoking vehicles the slope was 0.34 and the R2 was 0.95. The average ratio of IC sulfur to XRF sulfur for all vehicles in the winter was 0.44, 0.39, and 0.40 for FTP phases 1 3, respectively. Removing the diesels or smokers from the average had little effect on these ratios. Overall, it is apparent that while total sulfur is well correlated with the IC sulfur, the majority of the sulfur is not emitted as water soluble sulfate. This is true for all three FTP phases. The non soluble sulfate sulfur may be a combination of organosulfur compounds and zinc dithiophosphate, both of which are present in motor oil. Motor oil is 77 clearly a major contributor to the PM mass in many of the samples. Analytical errors can't be ruled out. However, the extractions and analyses were performed by the same laboratory that analyzed the NFRAQS ambient samples. Good agreement was found between sulfate and XRF for these samples ( Chow et al., 1998).

Fuel sulfur. For well maintained vehicles, most of the sulfur emitted in the exhaust comes from the fuel. The predominant combustion product of fuel sulfur is sulfur dioxide. A very small fraction is oxidized to sulfate, or is emitted in its original form as unburned fuel organosulfur compounds. For vehicles with high oil consumption, some of the sulfur can come from the oil as well. To put the sulfate emission rates discussed above into perspective, it is necessary to know the fuel sulfur content. Fuel sulfur was not determined for individual vehicles. However, fuel samples were collected at the pump from local service stations during both the summer and winter studies. In addition, the American Automobile Manufacturers Association ( AAMA) conducts a gasoline survey in Denver each summer and winter and reports fuel sulfur content as well as other fuel properties. These are also gasoline service station samples. The samples collected in our program were chosen to complement the AAMA data base.

Table 6.6 gives the results for the samples collected in this program. Summer samples were collected September 19, 1996. There were two regular, five mid grade and seven premium grade gasoline samples and two # 2 diesel fuel samples. The average weight % sulfur was 0.0329, 0.0178, 0.0146, and 0.0342, respectively. For the winter, samples were collected February 10, 1997. There were three regular, five mid grade, and eight premium gasoline samples, together with four # 2 diesel fuels and one off road diesel fuel. The weight % sulfur content averaged 0.0148, 0.0193, 0.0109, 0.0358, and 0.300, respectively. In the winter, five fuel samples were analyzed at separate laboratories. Results for these analyses are given in the last column of Table 6.4. The average ratio between the results from the separate laboratories was 1.08. The greatest difference was 24%.

The AAMA Denver 1996 summer survey ( AAMA, 1996) analyzed 15 regular grade, one intermediate grade, and two premium grade gasoline samples, as well as nine # 2 diesel fuel samples. Each sample within a grade category was from a different brand service station. Average sulfur content of the samples was 0.036, 0.017, 0.011, and 0.034 wt. %, respectively. The winter survey analyzed 16 regular grade, one mid grade, and two premium grade gasoline samples and 10 # 2 diesel fuel samples. Average sulfur content was 0.024, 0.010, 0.008, and 0.033 wt. %, respectively. Note that these are not sales weighted averages. The required information for sales weighting was not available. Results from both this study and the AAMA are summarized in Table 6.7. Included in Table 6.7 is the sulfur content average for results from both AAMA and this program.

Table 6.6. Fuel Sulfur Analysis Sample No. Brand Brand Name Fuel Grade Octane Rating Pump No. Address Sulfur, wt % Sample No. Sulfur, wt % Sulfur, wt % Summer Winter 78 1 Conoco Unleaded Plus Mid grade 87 2 13690 E. Colfax 0.0142 13 0.0166 2 Conoco Super Unleaded Premium 91 4 0.0054 12 0.0127 4 Citgo Mid grade Unleaded Mid grade 87 2 14490 E. Colfax 0.0337 14 0.0353 5 Citgo Super Premium Premium 91 2 0.0251 15 0.0277 6 Phillips 66 Super Clean Premium Unleaded Premium 91 1 14491 E. Colfax 0.0077 3 0.0081 7 Phillips 66 Mid Octane Unleaded Plus Mid grade 87 1 0.0073 4 0.0126 8 Phillips 66 Unleaded Regular Regular 85 1 0.0079 5 0.0135 9 Texaco Super Unleaded Premium 91 7 14081 E. Colfax 0.0116 7 0.0086 10 Texaco Power Plus Premium 87 7 0.0246 6 0.0087 11 Sinclair Unleaded Regular 85 5 15291 E. Colfax 0.0579 1 0.0278 12 Sinclair Super Unleaded Premium 91 3 0.0199 2 0.0174 14 Total Unleaded Plus Mid grade 87 3 1190 S. Chambers 0.0120 16 0.0178 15 Total Premium Unleaded Premium 91 3 0.0077 17 0.0037 Total Regular Unleaded Regular 85 3 1190 S. Chambers 20 0.0032 16 Amoco Silver Mid grade 87 1 15300 E. Mississippi 0.0212 18 0.0142 Amoco Ultimate Lead Free Premium Premium 91 1 15300 E. Mississippi 19 0.0109 3 Conoco Diesel 3 13690 E. Colfax 0.0344 11 0.0346 0.028a Conoco Diesel Premium Premium Diesel 14 1100 S. Havana 9 0.0348 0.030a 13 Sinclair Diesel 2 15291 E. Colfax 0.0340 8 0.0352 0.032a Total Premium Diesel Premium Diesel Cetane 50 12796 E. Colfax 10 0.0387 0.040a Conoco Off road # 2 Diesel Off road 21 0.2996 0.3233b a) analysis by Total Petroleum b) analysis by Conoco Table 6.7. Average Fuel Sulfur Fuel Summer Winter CRC AAMA Wt. Ave. CRC AAMA Wt. Ave. # % S # % S % S # % S # % S % S Regular 2 0.034 15 0.036 0.036 3 0.015 16 0.024 0.023 Mid grade 5 0.018 1 0.017 0.018 5 0.019 1 0.010 0.018 Premium 7 0.015 2 0.011 0.014 8 0.011 2 0.008 0.010 # 2 Diesel 2 0.034 9 0.034 0.034 4 0.036 10 0.033 0.034 Off road Diesel 0 ND ND ND ND 1 0.300 ND ND 0.300 A vehicle operating with a fuel economy of 20 mpg on a 0.02 wt. % sulfur fuel consumes approximately 31 mg/ mi sulfur. While some sulfur is stored on the catalyst, over time essentially all fuel sulfur is expected to be emitted in the exhaust. The non smoking gasoline vehicle sulfate emission rate averaged 0.4 mg/ mi., which is an average sulfatesulfur emission rate of 0.13 mg/ mi. Thus, on average, the conversion of fuel sulfur to sulfate was approximately 0.4% for the non smoking gasoline vehicles ( assuming 20 mpg fuel economy). Of course, it is also possible that some of the observed sulfate sulfur 79 derives from the combustion of motor oil.

XRF elements. Emission rates of various elements are of interest since they constitute part of the mobile source PM source signature used in source/ receptor modeling. Trace metals are of interest because one of the hypotheses for human health effects of PM involves reactions catalyzed by transition metals. Also, some metals are considered to be air toxics. Emission rates for 40 elements were obtained by XRF. Of these, only 12 elements had emission rates that averaged higher than the measurement uncertainty for the summer samples while 14 elements averaged higher than the measurement uncertainty for the winter samples. Table 6.8 lists the 40 elements and the average uncertainty of the measurement associated with each element in the summer and winter for the Teflo filters. Uncertainties were higher for the Pallflex T60A20 filters. This table gives the lower quantifiable limits for elements that were not detected. The average FTP emission rates by vehicle category for quantifiable elements are listed in Table 6.9 for the summer and Table 6.10 for the winter. Also given in the tables are the minimum and maximum emission rates for each category. The emission rates for each element averaged less than one mg/ mi for the non smoking gasoline vehicles, with the exception of silicon for the summer 1971 80 vehicles, and iron for the 1971 80 and the 1981 85 winter vehicles. The summer silicon emission rate of 2.5 mg/ mi is dominated by one high emitting vehicle. Smoking vehicles have higher emission rates for most of the elements, in line with their overall higher PM rate. Emission rates for the diesels were higher than for gasoline, with silicon, sulfur, calcium, iron and zinc all exceeding an average of one mg/ mi in the summer. Zinc and silicon are not reported for diesels in the winter because of the high filter background for these elements.

Table 6.11 gives the average emission rate for the elements as the percent of the average FTP PM mass emission rate for each vehicle category. On a percent basis, the diesel emissions do not appear uniquely high. The sum of the 12 elements account for only 0.77 percent of the average PM mass for the smokers, but 9.0 percent of the PM mass for the 1991 96 vehicles for the summer vehicles. The latter, however, is dominated by the relatively high contribution of silicon. This was not seen for the winter 1991 96 vehicles which had a 3.2 percent contribution of the elements to the PM mass, and only a 0.28 percent contribution from silicon. Winter smokers and diesels have a low percent contribution to the PM mass in part due to inability to measure some of the elements. Overall, it is seen that these elements are a relatively small contributor to the PM mass. 80 The average summer FTP emission rates of the elements are presented graphically in Figure 6.15 for the gasoline vehicles only; diesel results were omitted to avoid compressing the scale. Note that the silicon emission rate for 1971 80 vehicles is off scale. Figure 6.16 compares the winter emission rates for all vehicles. Rates tend to decrease with decreasing age of the vehicles.

Correlating the emission rates of the elements gives some information regarding their source. Zinc and phosphorus most likely are derived from motor oil, since zinc dithiophosphate is a standard anti wear and anti oxidant oil additive. Thus, it is not surprising that Figure 6.17 shows a high correlation ( R2= 0.90) between these species for the summer gasoline vehicles. The winter gasoline vehicles had the same correlation ( R2= 0.90) but a slope of 1.7 vs. 1.5 for the summer. Calcium and magnesium are present in motor oil as detergent additives and copper is added as an antioxidant. These elements also correlate reasonably well with phosphorus, with R2 values of 0.77, 0.68, and 0.63, respectively, for the summer and 0.95, 0.86, and 0.93, respectively, for the winter. On the other hand, sulfur is expected to be predominantly from the gasoline, yet it also correlates moderately well with phosphorus with R2 = 0.63 in the summer and 0.79 in the winter, suggesting that a significant fraction may be derived from the motor oil. The correlation shown in Figure 6.18 between summer phosphorus and PM mass, R2= 0.29, suggests that much more than oil consumption is involved in the production of PM, which is predominantly carbonaceous material. The R2 for the winter correlation between phosphorus and PM mass was 0.52.

Silicon is sometimes present as an additive to motor oil, but is not added to gasoline since it can damage emission control components. However, the silicon emission rate did not correlate with phosphorus ( R2= 0.03 in the summer and R2= 0.21 in the winter). This could simply indicate that the silicon concentration in motor oil is highly variable. Silicon could also be present from the ingestion of road dust. PM 2.5 road dust composition was determined as part of the NFRAQS study. The ratio of silicon to iron, aluminum, and calcium averaged 1/ 0.19/ 0.32/ 0.15 ( Eric Fujita, private communication). The same ratios for the summer and winter exhaust PM 10 ( which is mostly PM 2.5), were 1/ 0.35/ 0.11/ 0.80 and 1/ 1.97/ 0.25/ 0.36, respectively. The summer 1971 80 exhaust ratios were excluded from the average since the silicon appeared to be anomalously high. The ambient and exhaust ratios indicate that road dust could be a significant contributor to all of these species. To further explore this possibility, additional correlations were examined. While iron and aluminum were weakly correlated ( R2= 0.44 in the summer and 0.58 in the winter), neither was correlated with silicon in the summer and they were weakly correlated with silicon in the winter ( R2= 0.56 for iron and 0.30 for aluminum). Thus, the relative importance of wear and corrosion products, oil consumption, and road dust ingestion can not be determined from the data. An additional source of silicon could be gasket grease, but it seems unlikely that this would contribute significantly to the emissions from older vehicles.

Tables 6.12 and 6.13 give the average emission rates as a function of FTP phase for the summer and winter vehicles. Emission rates tend to be highest during the cold start portion of the test, and lowest during hot, stabilized operation. The same general pattern 81 is observed for total PM mass emission rates.

Table 6.8. Average Uncertainties in the XRF Measurement of Elements on Teflon Membrane Filters Element Summer, mg/ mi Winter, mg/ mi Element Summer, mg/ mi Winter, mg/ mi Sodium 0.1993 0.1116 Selenium 0.0046 0.0027 Magnesium 0.0375 0.0298 Bromine 0.0044 0.0020 Aluminum 0.0357 0.0167 Rubidium 0.0038 0.0023 Silicon 0.0200 0.0115 Strontium 0.0039 0.0022 Phosphorus 0.0143 0.0074 Yttrium 0.0050 0.0032 Sulfur 0.0120 0.0092 Zirconium 0.0057 0.0031 Chlorine 0.0287 0.0128 Molybdenum 0.0100 0.0057 Potassium 0.0204 0.0091 Palladium 0.0335 0.0186 Calcium 0.0206 0.0110 Silver 0.0369 0.0203 Titanium 0.0931 0.0524 Cadmium 0.0393 0.0222 Vanadium 0.0414 0.0223 Indium 0.0456 0.0257 Chromium 0.0137 0.0058 Tin 0.0572 0.0324 Manganese 0.0113 0.0054 Antimony 0.0680 0.0391 Iron 0.0083 0.0056 Barium 0.2520 0.1436 Cobalt 0.0134 0.0135 Lanthanum 0.3434 0.1946 Nickel 0.0071 0.0036 Gold 0.0219 0.0127 Copper 0.0070 0.0035 Mercury 0.0105 0.0061 Zinc 0.0072 0.0039 Thallium 0.0099 0.0068 Gallium 0.0074 0.0049 Lead 0.0098 0.0058 Arsenic 0.0131 0.0181 Uranium 0.0091 0.0051 Table 6.9. Summer FTP Emission Rates for Elements Identified by XRF Category Stats. PM Mg Al Si P S Cl Ca Fe Cu Zn Br Pb Sum  mg/ mi  1971 80 mean 102.2 0.029 0.018 2.516 0.094 0.512 0.230 0.071 0.113 0.012 0.099 0.012 0.043 3.75 min 21.2 0.003 0.009 0.126 0.026 0.114 0.006 0.043 0.021 0.003 0.060 0.001 0.008 max 254.6 0.090 0.036 13.503 0.198 1.829 1.218 0.092 0.243 0.030 0.179 0.061 0.095 1981 85 mean 42.5 0.009 0.010 0.211 0.071 0.147 0.007 0.136 0.060 0.011 0.108 0.000 0.006 0.78 min 3.2 0.000 0.003 0.030 0.021 0.031 0.000 0.038 0.025 0.001 0.031 0.000 0.001 max 99.8 0.031 0.021 0.636 0.164 0.252 0.025 0.371 0.220 0.031 0.214 0.000 0.019 1986 90 mean 85.8 0.046 0.041 0.129 0.115 0.225 0.012 0.170 0.088 0.025 0.186 0.000 0.027 1.07 min 1.3 0.000 0.000 0.024 0.001 0.014 0.000 0.000 0.016 0.001 0.003 0.000 0.001 max 766.3 0.259 0.285 0.390 0.637 1.464 0.086 0.972 0.273 0.227 1.055 0.001 0.254 1991 96 mean 3.0 0.000 0.010 0.183 0.005 0.019 0.002 0.003 0.036 0.001 0.006 0.000 0.003 0.27 min 0.9 0.000 0.005 0.018 0.002 0.004 0.000 0.000 0.011 0.001 0.003 0.000 0.002 max 7.3 0.001 0.019 0.657 0.009 0.037 0.008 0.009 0.061 0.002 0.009 0.001 0.004 Smokers mean 281.7 0.148 0.029 0.249 0.241 0.629 0.039 0.312 0.085 0.019 0.369 0.009 0.035 2.17 min 94.0 0.015 0.010 0.112 0.131 0.233 0.020 0.120 0.024 0.002 0.077 0.000 0.000 max 551.5 0.365 0.046 0.426 0.454 0.992 0.074 0.629 0.188 0.049 0.645 0.044 0.155 Diesel mean 1175 0.402 0.303 3.189 0.634 4.504 0.139 1.329 3.151 0.019 1.731 0.009 0.150 15.6 min 143.3 0.000 0.060 1.096 0.036 0.840 0.050 0.074 0.202 0.002 0.129 0.002 0.010 max 3988 1.556 0.909 7.631 2.193 14.655 0.386 4.099 11.617 0.057 5.728 0.023 0.511 Table 6.10. Winter FTP Emission Rates for Elements Identified by XRF 82 Category Stats. PM Mg Al Si P S Cl Ca Fe Cu Zn Br Pb K Cr Sum  mg/ mi 1971 80 mean 108.7 0.078 0.090 0.714 0.225 0.581 0.068 0.241 1.013 0.018 0.246 0.057 0.222 0.027 0.021 3.603 1971 80 min 31.3 0.034 0.018 0.101 0.029 0.170 0.017 0.083 0.073 0.004 0.047 0.000 0.000 0.008 0.006 0.590 1971 80 max 276.1 0.125 0.190 2.406 0.676 1.366 0.156 0.440 2.759 0.036 0.446 0.305 0.834 0.049 0.048 9.837 1981 85 mean 42.6 0.064 0.103 0.371 0.150 0.505 0.028 0.181 1.074 0.015 0.236 0.028 0.103 0.020 0.017 2.893 1981 85 min 21.6 0.014 0.013 0.064 0.028 0.143 0.013 0.043 0.072 0.001 0.036 0.001 0.008 0.004 0.003 0.443 1981 85 max 55.1 0.098 0.215 0.768 0.277 0.931 0.038 0.289 2.929 0.027 0.393 0.090 0.308 0.045 0.033 6.440 1986 90 mean 25.0 0.051 0.098 0.132 0.079 0.217 0.041 0.126 0.236 0.009 0.149 0.002 0.019 0.015 0.010 1.183 1986 90 min 5.2 0.015 0.014 0.056 0.024 0.062 0.007 0.041 0.057 0.001 0.028 0.000 0.000 0.006 0.004 0.315 1986 90 max 73.9 0.128 0.401 0.333 0.291 0.736 0.092 0.368 0.596 0.041 0.639 0.006 0.071 0.026 0.017 3.747 1991 96 mean 39.9 0.046 0.035 0.110 0.097 0.316 0.014 0.139 0.293 0.013 0.190 0.001 0.019 0.012 0.007 1.294 1991 96 min 6.3 0.023 0.008 0.018 0.010 0.053 0.003 0.016 0.031 0.001 0.014 0.000 0.001 0.004 0.004 0.187 1991 96 max 123.0 0.086 0.057 0.181 0.255 0.712 0.023 0.390 0.832 0.037 0.466 0.004 0.061 0.019 0.012 3.135 Smoker mean 574.1 ND ND ND ND 2.114 0.127 0.401 1.885 0.064 ND 0.036 0.282 ND ND 4.909 Smoker min 179.4 ND ND ND ND 0.308 0.068 0.000 0.000 0.002 ND 0.000 0.003 ND ND 0.381 Smoker max 1349.9 ND ND ND ND 6.723 0.298 1.090 12.54 0.173 ND 0.146 1.596 ND ND 22.56 Diesel mean 537.5 ND ND ND ND 2.343 0.217 0.137 0.476 0.025 ND ND 0.142 ND ND 3.340 Diesel min 193.9 ND ND ND ND 0.917 0.050 0.000 0.023 0.000 ND ND 0.000 ND ND 0.990 Diesel max 933.2 ND ND ND ND 3.980 0.804 1.245 0.934 0.107 ND ND 0.695 ND ND 7.765 Table 6.11. Percent of Average FTP Mass Emission Rate Category Season Mg Al Si P S Cl Ca Fe Cu Zn Br Pb Sum  percent 1971 80 Summer 0.028 0.018 2.462 0.092 0.501 0.225 0.069 0.111 0.012 0.097 0.012 0.042 3.669 1981 85 Summer 0.021 0.024 0.496 0.167 0.346 0.016 0.320 0.141 0.026 0.254 0.000 0.014 1.835 1986 90 Summer 0.054 0.048 0.150 0.134 0.262 0.014 0.198 0.103 0.029 0.217 0.000 0.031 1.247 1991 96 Summer 0.000 0.333 6.100 0.167 0.633 0.067 0.100 1.200 0.033 0.200 0.000 0.100 9.000 Smokers Summer 0.053 0.010 0.088 0.086 0.223 0.014 0.111 0.030 0.007 0.131 0.003 0.012 0.770 Diesel Summer 0.034 0.026 0.271 0.054 0.383 0.012 0.113 0.268 0.002 0.147 0.001 0.013 1.327 1971 80 Winter 0.072 0.083 0.657 0.207 0.535 0.063 0.222 0.932 0.016 0.227 0.052 0.204 3.314 1981 85 Winter 0.149 0.242 0.870 0.351 1.185 0.066 0.424 2.521 0.036 0.553 0.065 0.241 6.789 1986 90 Winter 0.204 0.391 0.526 0.317 0.868 0.165 0.504 0.942 0.036 0.596 0.006 0.075 4.727 1991 96 Winter 0.115 0.087 0.276 0.243 0.792 0.035 0.349 0.734 0.033 0.475 0.004 0.048 3.240 Smoker Winter ND ND ND ND 0.368 0.022 0.070 0.328 0.011 ND 0.006 0.049 0.855 Diesel Winter ND ND ND ND 0.436 0.040 0.026 0.089 0.005 ND ND 0.026 0.621 83 Table 6.12. Summer Average Emission Rates of XRF Elements by FTP Phase Category Phase Mass Mg Al Si P S Cl Ca Fe Cu Zn Br Pb  mg/ mi  1971 80 1 327 0.068 0.041 10.711 0.208 1.997 1.031 0.190 0.371 0.031 0.271 0.053 0.112 1971 80 2 43.4 0.019 0.010 0.426 0.051 0.111 0.025 0.032 0.030 0.006 0.034 0.002 0.015 1971 80 3 44.8 0.018 0.017 0.331 0.092 0.160 0.019 0.057 0.078 0.011 0.095 0.001 0.044 1981 85 1 108 0.031 0.017 0.326 0.162 0.393 0.017 0.264 0.129 0.030 0.260 0.001 0.016 1981 85 2 23.9 0.003 0.006 0.201 0.026 0.069 0.004 0.073 0.030 0.003 0.037 0.000 0.002 1981 85 3 28.4 0.005 0.011 0.141 0.088 0.111 0.006 0.162 0.066 0.011 0.129 0.000 0.006 1986 90 1 100 0.089 0.071 0.166 0.211 0.319 0.014 0.290 0.195 0.034 0.327 0.000 0.041 1986 90 2 13.0 0.033 0.028 0.136 0.073 0.237 0.014 0.141 0.046 0.019 0.123 0.000 0.020 1986 90 3 81.9 0.060 0.039 0.125 0.175 0.273 0.011 0.275 0.111 0.025 0.274 0.000 0.031 1991 96 1 6.35 0.000 0.012 0.231 0.010 0.034 0.008 0.011 0.092 0.003 0.013 0.001 0.005 1991 96 2 2.30 0.001 0.010 0.221 0.003 0.017 0.001 0.000 0.013 0.001 0.002 0.000 0.002 1991 96 3 1.94 0.000 0.007 0.075 0.004 0.010 0.002 0.002 0.036 0.001 0.006 0.000 0.002 Smoker 1 335 0.126 0.059 0.258 0.304 0.911 0.057 0.305 0.119 0.022 0.403 0.029 0.116 Smoker 2 225 0.178 0.022 0.225 0.175 0.472 0.037 0.181 0.031 0.022 0.279 0.004 0.010 Smoker 3 235 0.133 0.021 0.282 0.291 0.672 0.040 0.342 0.110 0.018 0.488 0.008 0.031 Diesel 1 2510 0.601 0.403 4.627 1.148 6.781 0.308 2.451 2.925 0.027 3.250 0.011 0.190 Diesel 2 437 0.197 0.103 1.234 0.248 1.736 0.070 0.438 0.614 0.005 0.594 0.005 0.048 Diesel 3 1568 0.639 0.607 5.819 0.982 8.040 0.144 2.185 8.133 0.039 2.756 0.015 0.313 Table 6.13. Winter Average Emission Rates of XRF Elements by FTP Phase Vehicle Phase Mass Mg Al Si P S Cl Ca Fe Cu Zn Br Pb K Cr  mg/ mi  1971 80 1 401 0.170 0.257 2.064 0.732 2.028 0.143 0.662 3.699 0.056 0.807 0.206 0.769 0.066 0.007 1971 80 2 37 0.050 0.049 0.373 0.082 0.212 0.052 0.137 0.290 0.007 0.098 0.022 0.041 0.016 0.005 1971 80 3 35 0.063 0.047 0.399 0.127 0.247 0.044 0.135 0.435 0.010 0.123 0.012 0.167 0.021 0.006 1981 85 1 43 0.084 0.123 0.339 0.165 0.698 0.030 0.198 1.729 0.019 0.306 0.047 0.162 0.024 0.019 1981 85 2 24 0.030 0.058 0.417 0.062 0.221 0.030 0.082 0.339 0.006 0.106 0.006 0.026 0.011 0.015 1981 85 3 37 0.077 0.102 0.343 0.165 0.540 0.031 0.195 1.164 0.019 0.263 0.029 0.108 0.020 0.014 1986 90 1 66 0.048 0.160 0.199 0.109 0.353 0.048 0.152 0.305 0.010 0.186 0.002 0.024 0.018 0.006 1986 90 2 12 0.043 0.061 0.103 0.046 0.134 0.043 0.098 0.172 0.006 0.092 0.001 0.013 0.014 0.005 1986 90 3 19 0.070 0.121 0.136 0.121 0.275 0.032 0.161 0.307 0.014 0.232 0.002 0.027 0.013 0.006 1991 96 1 128 0.111 0.088 0.283 0.301 0.992 0.028 0.424 0.806 0.043 0.615 0.004 0.058 0.026 0.005 1991 96 2 23 0.020 0.020 0.067 0.030 0.125 0.009 0.047 0.138 0.004 0.054 0.001 0.006 0.008 0.005 1991 96 3 10 0.050 0.026 0.068 0.084 0.211 0.012 0.121 0.242 0.011 0.153 0.001 0.019 0.010 0.007 Smoker 1 1369 ND ND ND ND 6.316 0.152 0.342 4.500 0.121 ND 0.113 0.514 ND ND Smoker 2 359 ND ND ND ND 0.775 0.128 0.376 0.471 0.034 ND 0.005 0.070 ND ND Smoker 3 398 ND ND ND ND 1.577 0.107 0.494 2.682 0.080 ND 0.038 0.519 ND ND Diesel 1 937 ND ND ND ND 5.524 0.430 0.274 1.625 0.054 ND ND 0.255 ND ND Diesel 2 410 ND ND ND ND 1.411 0.159 0.117 0.176 0.015 ND ND 0.097 ND ND Diesel 3 481 ND ND ND ND 1.732 0.164 0.073 0.181 0.021 ND ND 0.142 ND ND 84 Comparison of outdoor and indoor composition. The focus of this program was to characterize the composition of the PM from the winter outdoor samples, since those are the best characterization of the PM emitted into the winter Denver atmosphere. However, a limited comparison was done between the outdoor and indoor samples. Eleven phase 1 FTP samples from gasoline vehicles tested indoors were analyzed by IC and XRF for comparison to the outdoor samples. Phase 2 and 3 samples were not run, since they are not expected to be significantly affected by the ambient temperature. Results are given in Table 6.14. The NFRAQS number identifies the vehicle tested. The second column gives the outdoor PM 10 phase 1 FTP emission rate for that vehicle. The third column gives the ratio of outdoor to indoor PM emission rates. Note that while most vehicles had higher PM 10 emission rates outdoors, vehicles 345, 362, and 348 had lower rates. The following columns give the relative change in rate of the indicated species in relationship to the change in the PM 10 emission rate. For example, if the outdoor to indoor PM 10 emission rate ratio was 3.0, and the sulfate outdoor to indoor ratio was also 3.0, then the relative change in rate in Table 6.14 would be 1.0. Missing values indicate that one of the measured rates was below minimum quantifiable limit. Results are highly variable, with both large increases in some emission rates and large decreases in others.

Phase 1 FTP PM 10 filter samples were also analyzed for three smoking vehicles and three diesels. The samples used the Pallflex T60A20 filters that had high nitrate blanks and relatively high XRF detectable elements. Thus, the only legitimate comparison that could be made was for sulfate. This comparison is shown in Table 6.15. As with the gasoline vehicles, the sulfate tends to increase at a rate equal to or greater than the increase in the PM 10 rate.

Table 6.14. Relative Change in Phase 1 FTP Emission Rates Relative to the Change in PM Emission Rate NFRAQ # Outdoor PM, mg/ mi Out/ In PM Ratio Relative change in rate compared to change in PM rate NO3 SO4 Mg Al Si P S Cl Ca Fe Cu Zn Pb 317 22.2 3.43 0.32 0.52 1.80 0.17 0.36 0.36 0.19 0.16 349 13.1 5.84 0.11 0.17 0.66 0.60 0.73 0.46 0.37 8.61 323 40.7 3.17 0.87 6.93 1.74 1.79 1.44 1.99 0.92 1.56 2.03 335 72.3 1.43 0.62 9.86 1.71 9.29 5.46 0.58 7.11 18.19 16.37 336 38.3 7.37 0.36 0.70 0.32 0.63 1.01 0.57 0.60 0.80 4.04 0.63 345 71.2 0.55 1.41 0.88 3.79 1.87 0.75 3.14 1.27 1.11 1.99 0.38 3.80 3.15 1.12 362 115 0.60 1.27 1.49 2.30 0.10 2.17 1.50 0.61 1.98 5.53 3.27 2.44 1.76 348 89.7 0.94 8.89 0.67 5.69 0.75 0.38 1.75 0.72 0.50 1.55 1.60 2.31 1.78 342 204 8.51 0.39 0.24 0.50 0.49 0.51 1.06 1.28 0.35 1.14 1.40 1.27 1.61 3.11 322 1120 4.25 0.47 2.65 0.29 1.89 0.83 0.22 1.43 0.38 0.64 4.99 0.40 0.25 0.09 338 589 10.26 0.08 0.07 0.10 0.58 0.81 0.26 0.69 0.35 0.28 0.71 0.23 Mean 215.95 4.21 1.45 2.37 1.89 1.13 0.88 1.91 1.47 0.54 1.60 3.51 1.80 3.48 1.35 85 Table 6.15. Relative Change in Sulfate Emission Rate for Smoking and Diesel Vehicles NFRAQ # Category Outdoor PM mg/ mi Out/ In PM ratio SO4 ratio SO4 ratio/ Mass ratio 329 S 5951 1.56 9.81 6.30 326 S 130 1.03 1.60 1.56 321 S 2074 3.15 6.10 1.94 383 D 1467 1.30 2.15 1.66 389 D 377 1.57 1.85 1.18 391 D 596 1.13 1.70 1.50 Polynuclear aromatic hydrocarbons ( PAH). The primary purpose of measuring the PAHs was to provide additional compounds for use in creating source profiles. PAHs are also of interest as one of the five air toxics listed by the EPA as being important for mobile sources. As was noted earlier, PAH was determined on composited samples. Composites for non smoking gasoline vehicles were formed from vehicles having similar emission rates, regardless of the model year. These composites are identified as either being low emitters ( L), medium low emitters ( ML), medium emitters ( M), or high ( H) emitters. Thus, the non smoking gasoline vehicle PAH emissions data can not be examined using the vehicle model year categories used in the rest of the report. On the other hand, the carbon, anion, and elemental analyses discussed earlier were all performed on an individual vehicle basis. Thus, that data can be composited to match the PAH data.

Tables 6.16 and 6.17 list the 15 summer and 15 winter composite samples. No data are listed for winter L1 and H2 samples since one filter extract was lost from each of these. Samples labeled S and D are from smoking gasoline vehicles and diesel vehicles, respectively. The number of vehicles in each composite is also given in the Tables. For most samples it was two. Also given is the average FTP PM emission rate for the composite, the average FTP OC emission rate, and the average FTP PAH emission rate. Table 6.17 is organized so that the PM emission rate within an emitter category increases from top to bottom. The PAH emission rates include both gaseous and particulate compounds; i. e. those captured on the filter and those captured in the PUF/ XAD trap behind the filter. Since the extracts from the filters and PUF/ XAD traps were analyzed together, it is not possible to separate these by capture media. Naphthalene was the most abundant PAH present. However, there were significant and highly variable background naphthalene concentrations in the summer. Therefore, summer naphthalene emission rates are not reported, and all total PAH emission rates exclude naphthalene, unless otherwise noted.

Examination of Tables 6.16 and 6.17 shows that total PAH does not correlate closely with PM emission rates. The lowest summer PM emission rate sample, L1, has PAH emissions almost equal to PM emissions. Samples L2 and L3 have much higher average PM emission rates than L1, but essentially the same total PAH emission rate. Similarly, the highest total PAH rates for the high emitters, 10.4 mg/ mi, was for the sample with the 86 lowest PM emission rate, 45.4 mg/ mi. It is possible that the mixing of gas and particle phase PAH is confounding the relationship between PM and PAH. Tables 6.16 and 6.17 also list the average FTP OC emission rate. It would be logical to compare the PAH emission rates with the organic fraction of the PM rather than the total PM mass. Unfortunately, the problems in measuring the diesel and smoker summer carbon limit the utility of this approach for the smokers and diesels in the summer samples. Note, for example, that the summer S1 and S2 samples have more OC than PM mass. A regression of the winter OC vs. PAH showed considerable scatter, with an R2 of 0.48.

Sixty nine PAH compounds were determined in the summer samples and 65 were determined in the winter samples. The difference in number was due to the deletion of four compounds from the summer list that had negligible emission rates for vehicles. Table 6.18 lists the average summer emission rates of the individual PAHs for each emitter category. The compounds are listed in the same order that they are eluted from the GC. Thus the order corresponds, approximately, with their vapor pressure. Designation of a compound as A, B, etc. refers to isomers that have not been uniquely identified. Of the compounds listed, all but eight had concentrations that were significantly greater than the measurement uncertainty in the summer. The eight with high uncertainty relative to their concentrations were 1,8 dimenaphthalene, D trimethylnaphthalene, G methylpyrene, Retene, Benzonaphthothiophene, 7 Methylbenz[ a] anthracene, 7 Methylbenzo[ a] pyrene, and Dibenz( ah+ ac) anthracene. Figure 6.19 gives a graphical presentation of the average emission rates for summer high emitter samples. Note that the rates are plotted on a log scale and cover four orders of magnitude. Tables 6.18 and 6.19 also assign each PAH into a group. These groups are a somewhat arbitrary way of compositing the PAHs to facilitate comparison. They were selected after an examination of the variability of compounds between emitter categories and FTP phases. Compounds whose emission rates tended to change in a similar manner were grouped together. Generally, isomers were lumped into the same group. These groups can be viewed primarily as PAHs with similar volatilities.

The PAHs can be formed during combustion or can be unburned components of the fuel and motor oil. It was beyond the scope of this program to test individual fuel and motor oil samples for PAH content. Therefore, it is not possible to determine the sources of observed PAH. Some of the observed emission variability is likely due to differences in composition of the fuel and motor oil, as well as differences in the relative contributions that the fuel and motor oil make to the PM from different vehicles.

The suitability of using these compounds for source profiles was judged qualitatively by comparing the emission rates between samples. The wide range in concentrations of the individual PAHs makes graphical comparisons on a concentration basis difficult. Therefore, the ratios of individual compounds were compared. This was done in three steps. First, the consistency between composites within the same emitter category was examined. Second, the composites in each category were averaged, and the average composites were compared. These averages were not weighted by emission rate. Third, differences between the three FTP phases were examined for the average composites. 87 An example of the consistency in relative emission rates within an emitter category is shown in Figure 6.20 which plots the ratios between summer sample composites L2 and L3. Missing ratios are for species whose rates were below the detection limit for at least one of the samples. There is good overall agreement for most compounds. Somewhat more variability was observed for the ratios of L3 and L2 with L1, probably because L1 was the lowest emission rate sample. Differences between samples were greater for the summer medium, high and smoker categories. This is illustrated in Figure 6.21, which Table 6.16. Average Summer FTP Emission Rates for the Composite PAH Samples Sample No. of Vehicles PM Emission Rate, mg/ mi OC Emission Rate, mg/ mi PAH Emission Rate, mg/ mi L1 3 2.03 3.68 1.98 L2 2 6.86 4.94 1.82 L3 2 9.45 6.94 2.32 Average 6.11 5.19 2.03 M1 2 22.4 8.76 3.46 M2 2 20.5 9.43 3.95 M3 2 30.4 14.8 9.19 Average 24.4 11.0 5.51 H1 2 45.4 22.2 10.4 H2 2 60.7 64.6 4.43 H3 2 105 58.8 9.28 Average 70.5 48.5 8.05 S1 2 497 529 18.6 S2 2 163 222 29.9 S3 2 186 123 45.5 Average 282 291 31.3 D1 2 213 143 34.2 D2 1 289 227 49.9 D3 1 3990 2879 53.0 Average 1497 1083 45.6 Table 6.17. Average Winter FTP Emission Rates for the Composite PAH Samples Sample No. of Vehicles PM, mg/ mi OC, mg/ mi PAH, mg/ mi PAH w/ o napht, mg/ mi L2 3 7.2 5.7 4.45 2.98 88 ML2 2 21.2 12.5 25.30 14.72 ML1 3 35.3 13.7 10.01 5.92 average 28.3 13.1 17.7 10.3 M3 3 50.2 27.8 18.93 13.68 M2 2 54.6 19.9 16.75 10.23 M1 3 79.4 55.4 23.54 15.09 average 61.4 34.4 19.7 13.0 H1 2 212.6 64.1 75.71 38.88 S3 2 201.0 158.2 19.61 11.42 S2 3 601.6 455.1 39.26 24.32 S1 3 1091.8 431.7 170.96 104.42 average 631.5 348.3 76.6 46.7 D5 3 346.1 142.2 7.87 7.07 D4 2 427.3 47.5 12.12 9.00 D3 2 534.0 57.8 21.79 17.18 D2 2 627.8 152.6 42.55 37.48 D1 2 848.1 259.6 58.36 47.57 average 556.7 131.9 28.5 23.7 Table 6.18. Average Summer PAH FTP Emission Rates ID Group Compound Ave L Ave M Ave H Ave S Ave D  mg/ mi  1 1 2 menaphthalene 0.734 2.059 2.764 11.026 6.053 2 1 1 menaphthalene 0.341 1.147 1.528 6.108 4.421 3 1 2,6+ 2,7 dimenaphthalene 0.072 0.214 0.343 1.334 1.579 4 1 1,7+ 1,3+ 1,6 dimenaphthalene 0.136 0.362 0.620 2.653 3.680 5 1 2,3+ 1,4+ 1,5 dimenaphthalene 0.043 0.140 0.217 0.869 1.285 6 1 1,2 dimenaphthalene 0.018 0.062 0.095 0.476 0.523 7 1 1,8 dimenaphthalene 0.000 0.000 0.000 0.005 0.000 8 2 Biphenyl 0.037 0.068 0.095 0.336 1.051 9 2 A Methylbiphenyl 0.003 0.002 0.003 0.005 0.039 10 2 2 Methylbiphenyl 0.005 0.013 0.019 0.075 0.341 11 2 B Methylbiphenyl 0.007 0.016 0.018 0.070 0.222 12 2 3 Methylbiphenyl 0.022 0.052 0.069 0.258 1.625 13 2 4 Methylbiphenyl 0.011 0.026 0.032 0.119 0.632 14 2 C Methylbiphenyl 0.028 0.047 0.065 0.196 1.098 15 3 A Trimethylnaphthalene 0.033 0.106 0.174 0.597 1.651 16 3 1 Ethyl 2 methylnaphthalene 0.010 0.033 0.048 0.183 0.415 17 3 B Trimethylnaphthalene 0.030 0.101 0.182 0.674 2.022 18 3 C Trimethylnaphthalene 0.028 0.096 0.156 0.589 1.993 19 3 2 Ethyl 1 methylnaphthalene 0.002 0.014 0.020 0.052 0.120 20 3 D Trimethylnaphthalene 0.000 0.000 0.000 0.000 0.000 21 3 E Trimethylnaphthalene 0.018 0.060 0.101 0.399 1.431 22 3 F Trimethylnaphthalene 0.011 0.035 0.058 0.225 0.720 23 3 G Trimethylnaphthalene 0.015 0.035 0.065 0.286 0.935 24 3 H Trimethylnaphthalene 0.0029 0.0129 0.0196 0.0826 0.2009 25 3 1,2,8 Trimethylnaphthalene 0.0061 0.0136 0.0213 0.0551 0.5416 26 4 Acenaphthylene 0.027 0.142 0.424 1.519 0.773 89 27 4 Acenaphthene 0.015 0.024 0.047 0.173 0.180 28 4 Phenanthrene 0.010 0.069 0.086 0.405 1.419 29 4 Fluorene 0.025 0.079 0.147 0.440 0.758 30 4 1 Methylfluorene 0.012 0.030 0.037 0.138 0.551 31 4 B Methylfluorene 0.005 0.014 0.017 0.067 0.375 32 4 C Methylfluorene 0.047 0.048 0.059 0.172 0.747 33 5 A Methylphenanthrene 0.021 0.033 0.032 0.091 0.815 34 5 2 Methylphenanthrene 0.026 0.037 0.037 0.104 0.902 35 5 B Methylphenanthrene 0.0041 0.0088 0.0116 0.0338 0.0437 36 5 C Methylphenanthrene 0.0117 0.0182 0.0211 0.0562 0.5553 37 5 1 Methylphenanthrene 0.0133 0.0193 0.0192 0.0534 0.4512 38 5 3,6 Dimethylphenanthrene 0.0061 0.0080 0.0073 0.0231 0.2347 39 5 A Dimethylphenanthrene 0.0083 0.0105 0.0092 0.0310 0.3099 40 5 B Dimethylphenanthrene 0.0042 0.0052 0.0045 0.0153 0.1462 41 5 C Dimethylphenanthrene 0.0118 0.0156 0.0148 0.0488 0.5358 41 5 1,7 Dimethylphenanthrene 0.0061 0.0086 0.0079 0.0262 0.2231 43 5 D Dimethylphenanthrene 0.0038 0.0047 0.0036 0.0130 0.1380 44 5 E Dimethylphenanthrene 0.0055 0.0090 0.0059 0.0956 0.1913 45 6 Anthracene 0.0220 0.0481 0.0572 0.1466 0.5619 46 6 9 Methylanthracene 0.00084 0.00097 0.00130 0.00354 0.02005 47 6 Fluoranthene 0.04839 0.04743 0.07047 0.17579 0.89560 48 6 Pyrene 0.05564 0.05206 0.08402 0.30144 1.05026 49 6 A Methylpyrene 0.00575 0.00716 0.00847 0.00926 0.06618 50 6 B Methylpyrene 0.00307 0.00371 0.00417 0.01893 0.06110 51 6 C Methylpyrene 0.00535 0.00677 0.00909 0.04189 0.11719 52 6 D Methylpyrene 0.00193 0.00276 0.00441 0.02112 0.03465 53 6 E Methylpyrene 0.00239 0.00312 0.00388 0.01806 0.09252 54 6 F Methylpyrene 0.00159 0.00268 0.00428 0.01875 0.07317 55 6 G Methylpyrene 0.00000 0.00000 0.00000 0.00000 0.00000 56 7 Retene 0.00000 0.00008 0.00000 0.00024 0.00227 57 7 Benzonaphthothiophene 0.00000 0.00009 0.00028 0.00189 0.00355 58 7 Benz( a) anthracene 0.00159 0.00380 0.00821 0.02872 0.07683 59 7 7 Methylbenz[ a] anthracene 0.00004 0.00013 0.00018 0.00059 0.00080 60 7 Chrysene 0.00126 0.00374 0.00850 0.03280 0.15281 61 7 Benzo( b+ j+ k) fluoranthene 0.00007 0.00294 0.01250 0.03526 0.11486 62 7 Benzo[ e] pyrene 0.00035 0.00276 0.00978 0.02835 0.05881 63 7 Benzo[ a] pyrene 0.00052 0.00247 0.01068 0.04167 0.03923 64 7 7 Methylbenzo[ a] pyrene 0.00012 0.00017 0.00023 0.00040 0.00162 65 7 Indeno[ 123 cd] pyrene 0.00033 0.00204 0.00791 0.02076 0.04757 66 7 Dibenz( ah+ ac) anthracene 0.00007 0.00033 0.00087 0.00158 0.00380 67 7 Benzo( b) chrysene 0.00808 0.01281 0.01497 0.02729 0.12681 68 7 Benzo( ghi) perylene 0.00089 0.00578 0.01832 0.09187 0.08292 69 7 Coronene 0.00046 0.00265 0.00932 0.05404 0.02068 Total PAH ( w/ o Naphth) 2.03 5.51 8.05 31.30 45.63 90 Table 6.19. Average Winter PAH FTP Emission Rates ID Group Compound L2 Ave ML Ave M H1 Ave S Ave D  mg/ mi  1 0 Naphthalene 1.465 7.334 6.737 36.829 29.892 4.877 2 1 2 menaphthalene 0.714 3.600 3.754 12.607 13.551 2.821 3 1 1 menaphthalene 0.337 1.943 1.969 6.900 7.571 2.131 4 1 2,6+ 2,7 dimenaphthalene 0.067 0.399 0.462 1.722 2.524 1.413 5 1 1,7+ 1,3+ 1,6 dimenaphthalene 0.085 0.594 0.679 2.644 3.560 2.113 6 1 2,3+ 1,4+ 1,5 dimenaphthalene 0.028 0.190 0.213 0.843 1.242 0.888 7 1 1,2 dimenaphthalene 0.012 0.087 0.094 0.278 0.566 0.288 8 1 1,8 dimenaphthalene 0.0000 0.0022 0.0016 0.0087 0.0163 0.0054 9 2 Biphenyl 0.0293 0.1154 0.1509 0.5320 0.5228 0.6945 10 2 2 Methylbiphenyl 0.0000 0.0087 0.0177 0.0985 0.0919 0.1884 11 2 3 Methylbiphenyl 0.0176 0.0698 0.1084 0.3202 0.3769 0.9959 12 2 4 Methylbiphenyl 0.0095 0.0358 0.0567 0.1510 0.1788 0.4248 13 3 A Trimethylnaphthalene 0.0243 0.1313 0.1631 0.4863 0.8941 0.9944 14 3 1 Ethyl 2 methylnaphthalene 0.0076 0.0388 0.0494 0.1380 0.2549 0.2580 15 3 B Trimethylnaphthalene 0.0237 0.1350 0.1825 0.5087 0.9237 1.0971 16 3 C Trimethylnaphthalene 0.0258 0.1308 0.1804 0.4964 0.9136 1.3156 17 3 2 Ethyl 1 methylnaphthalene 0.0018 0.0078 0.0098 0.0249 0.0778 0.0599 18 3 D Trimethylnaphthalene 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 19 3 E Trimethylnaphthalene 0.0153 0.0884 0.1231 0.3432 0.6214 1.0090 20 3 F Trimethylnaphthalene 0.0205 0.0946 0.1332 0.3449 0.6251 0.9230 21 3 G Trimethylnaphthalene 0.0105 0.0457 0.0723 0.1850 0.3392 0.3992 22 3 1,2,8 Trimethylnaphthalene 0.0007 0.0016 0.0040 0.0050 0.0910 0.0297 23 4 Acenaphthylene 0.0868 0.3299 0.6858 1.6119 3.2736 0.3791 24 4 Acenaphthene 0.0441 0.0949 0.0566 0.1478 0.1747 0.0890 25 4 Phenanthrene 0.3355 0.5740 1.1630 2.0699 2.5742 1.2781 26 4 Fluorene 0.0522 0.1358 0.2222 0.4868 0.7726 0.4077 27 4 A Methylfluorene 0.0230 0.0657 0.1110 0.2382 0.3672 0.3912 28 4 1 Methylfluorene 0.0125 0.0295 0.0519 0.0961 0.1713 0.2715 29 4 B Methylfluorene 0.0061 0.0159 0.0246 0.0433 0.0828 0.0838 30 4 C Methylfluorene 0.0525 0.1469 0.2648 0.5462 0.6345 0.2070 31 5 A Methylphenanthrene 0.0486 0.0617 0.1160 0.2303 0.2362 0.2951 32 5 2 Methylphenanthrene 0.0603 0.0716 0.1262 0.2429 0.2569 0.3150 33 5 B Methylphenanthrene 0.0076 0.0207 0.0340 0.0274 0.0575 0.0249 34 5 C Methylphenanthrene 0.0339 0.0482 0.0808 0.1303 0.1578 0.2352 35 5 1 Methylphenanthrene 0.0398 0.0484 0.0806 0.1400 0.1458 0.1758 36 5 3,6 Dimethylphenanthrene 0.0151 0.0181 0.0244 0.0545 0.0442 0.0846 37 5 A Dimethylphenanthrene 0.0198 0.0206 0.0311 0.0683 0.0495 0.0967 38 5 B Dimethylphenanthrene 0.0099 0.0108 0.0156 0.0342 0.0250 0.0504 39 5 C Dimethylphenanthrene 0.0313 0.0360 0.0503 0.0929 0.0861 0.1833 40 5 1,7 Dimethylphenanthrene 0.0141 0.0194 0.0247 0.0429 0.0390 0.0852 41 5 D Dimethylphenanthrene 0.0078 0.0093 0.0130 0.0248 0.0227 0.0534 42 5 E Dimethylphenanthrene 0.0136 0.0147 0.0212 0.0428 0.0339 0.0586 43 6 Anthracene 0.1238 0.1278 0.2805 0.5430 0.6093 0.2246 44 6 9 Methylanthracene 0.0050 0.0044 0.0077 0.0198 0.0136 0.0122 45 6 Fluoranthene 0.2182 0.2668 0.4352 1.0176 0.5869 0.1810 46 6 Pyrene 0.2565 0.3561 0.5585 1.4643 0.7531 0.2089 47 6 B Methylpyrene 0.0048 0.0059 0.0081 0.0219 0.0150 0.0094 48 6 C Methylpyrene 0.0120 0.0155 0.0202 0.0557 0.0397 0.0237 49 6 D Methylpyrene 0.0048 0.0074 0.0091 0.0240 0.0212 0.0092 50 6 E Methylpyrene 0.0036 0.0058 0.0066 0.0211 0.0154 0.0167 91 51 6 F Methylpyrene 0.0056 0.0065 0.0080 0.0313 0.0191 0.0150 52 7 Retene 0 0 0 0 0 0 53 7 Benzonaphthothiophene 0.00000 0.00052 0.00053 0.00185 0.00360 0.00146 54 7 Benz( a) anthracene 0.00153 0.00437 0.00504 0.03413 0.03546 0.01654 55 7 7 Methylbenz[ a] anthracene 0.00000 0.00000 0.00000 0.00059 0.00072 0.00010 56 7 Chrysene 0.00153 0.00479 0.00560 0.03782 0.03208 0.02381 57 7 Benzo( b+ j+ k) fluoranthene 0.00000 0.00728 0.00952 0.10682 0.08899 0.04631 58 7 Benzo[ e] pyrene 0.00020 0.00221 0.00349 0.05521 0.03757 0.01601 59 7 Benzo[ a] pyrene 0.00073 0.00312 0.00353 0.06513 0.04550 0.01083 60 7 7 Methylbenzo[ a] pyrene 0.00000 0.00000 0.00000 0.00099 0.00161 0.00227 61 7 Indeno[ 123 cd] pyrene 0.00000 0.00188 0.00257 0.04385 0.03870 0.00797 62 7 Dibenz( ah+ ac) anthracene 0.00000 0.00010 0.00007 0.00271 0.00343 0.00145 63 7 Benzo( b) chrysene 0.00000 0.00000 0.00000 0.00059 0.00230 0.00073 64 7 Benzo( ghi) perylene 0.00020 0.00548 0.00841 0.17844 0.12492 0.01512 65 7 Coronene 0.00047 0.00443 0.00603 0.14185 0.08425 0.00504 92 shows the ratios between PAH emission rates for H3 and H1. Note that the ratios show definite trends, with sample H3 having higher emission rates for the higher molecular weight compounds than sample H1. Also note that the variability is greatest for the last 13 compounds. This was generally the case. Finally, Figure 6.22 shows the one case where there were very large differences in the summer between different samples in an emission category. Sample D3 was a single diesel vehicle. It had much higher emissions than those in D2 and D1, and clearly had a much different PAH emissions profile than the vehicles in D1. On the other hand, D1 and D2 had very similar profiles. Similar variability in the relative emission rates of individual PAHs was seen in the winter samples as well. Since all of the PAHs are present in all of the samples, there are no distinct marker compounds that can be used to distinguish between PM emissions from non smoking gasoline vehicles and those of smoking gasoline vehicles or diesels. Thus, separations will have to rely on differences in the relative emission rates of the compounds. It is concluded that a careful analysis of the emissions variability is needed if these compounds are going to be used in source profiles. Such an analysis is beyond the scope of this report.

A comparison between emission rates of individual PAHs for the summer composite medium emitter gasoline and the composite smoker is shown in Figure 6.23. The smoking vehicles have more low and high molecular weight PAHs than the medium emission rate vehicles; however, the variability does not appear to be any greater than between some of the individual samples within the composites. The summer smokers and high emitters were in closer agreement than the smokers and medium emitters. The summer profile for the low emitters was different than that of the other categories, as shown in Figure 6.24. The high emitters clearly have much higher emission rates, on a relative basis, of the low and high molecular weight PAHs than do the low emission rate vehicles. Finally, Figure 6.25 shows the ratios between the diesel vehicles and the high emitters. The profiles are very different, with the diesels having relatively high emission rates for most of the midrange molecular weight compounds. Results were similar for the winter samples. The biggest difference between the diesel and gasoline vehicles is with the low molecular weight PAHs. All of these species remain in the gas phase. Therefore, they may not be good indicators of the PM emission rate. More work is needed to compare gas vs. particle bound PAHs as the tracers for these vehicle types. Such work is beyond the scope of this report.

There are also differences in PAH emission rate profiles between the three FTP phases. The differences were greatest for the low and medium emitting gasoline vehicles, which had relatively higher emissions of both the low and high molecular weight compounds during the cold start ( bag 1) than during bags 2 or 3. This difference is illustrated in Figures 6.26 and 6.27 which show the ratios between bags 1 and 2 and bags 1 and 3, respectively, for the summer medium emitting vehicles. For the high emitting vehicles the mid molecular weight range PAH emission rates were approximately half those of the low and high molecular weight PAHs in bag 1 compared to bag 2. For smoking vehicles the differences between bags 1 and 2 were mostly in the high molecular weight compounds, which had rates approximately double those of the low and mid molecular weight PAHs. Diesels had higher low range PAH emissions in bag 1 than 2 and 3. When generating profiles for source apportionment studies, these differences should be considered since the 93 local activity may be different from that assumed in the FTP weighting of the three bags.

While Figures 6.20   6.27 give a good visual indication of differences in PAH profiles, it is desirable to provide more quantitative comparisons. That was done by examining the lumped PAH emission rates in the groups defined in Tables 6.18 and 6.19. Tables 6.20 and 6.21 give the average PAH emission rates for the groups during the summer and winter. Note that the winter data includes a group 0, which consists only of naphthalene. It is not present in the summer data since the naphthalene data were invalidated. For comparison purposes, Tables 6.22 and 6.23 give the percent of the total PAH in each group for the summer and winter. Examination of these tables shows that variations within an emitter category are generally as large as differences between categories. The exception is the difference between the diesels and the gasoline vehicles. As noted earlier, the diesels have a lower percentage of the group 1 PAH compounds and a higher percentage of the group 2 and 3 PAH compounds ( see Table 6.18 for compound group designations).

Tables 6.24 and 6.25 give the percentage contribution of each group of PAH compounds to the total PAH as a function of FTP phase and vehicle category for the summer and the winter. The tables show that group 1 compounds are a lower percentage of the total PAH for phase 2 than for phases 1 and 3. The difference is made up in groups 3 6. The difference is greatest for the low emission gasoline vehicles, and decreases with increasing emission rate. The diesels show a similar, although small, difference between FTP phases. As noted before, the diesel vehicles have a lower group 1 PAH percentage, and higher group 2,3,5, and 6 percentage emissions.

PAH emission rates were also expressed as their percentage of the total PM emission rate. Results are given in Table 6.26 for the summer samples and Table 6.27 for the winter samples. These percentages are confounded by the fact that a large fraction of the measured PAHs are present in the gas phase. Partitioning between the gas and particle phases depends on a number of factors such as sample temperature and gas phase concentration and is likely to be different in the atmosphere than in exhaust samples. Group 1 2 compounds are most likely to be in gas phase; group 3 5 may be partitioned between phases and group 6 7 compounds are likely to be in the particle phase. The NFRAQS CMB analysis uses all of the PAHs to help apportion ambient particulate to gasoline and diesel vehicles. Therefore, it makes some sense to examine how all the PAHs compare to PM. Expressed in this manner the variability between samples is high, and distinctions between the diesels and the other vehicles is blurred.

Table 6.20. FTP Summer Emission Rates of the PAH Compounds Lumped into Groups ( Naphthalene not included)

Sample Sum PAH Group1 Group2 Group3 Group4 Group5 Group6 Group7 94  mg/ mi  L1 1.96 1.27 0.09 0.18 0.12 0.13 0.16 0.016 L2 1.82 1.23 0.10 0.12 0.12 0.10 0.13 0.010 L3 2.32 1.53 0.14 0.17 0.18 0.13 0.15 0.016 MI 3.46 2.61 0.12 0.26 0.21 0.12 0.10 0.041 M2 3.96 2.89 0.17 0.33 0.25 0.14 0.18 0.016 M3 9.12 6.45 0.37 0.94 0.76 0.28 0.25 0.063 H1 10.45 7.73 0.36 1.13 0.91 0.12 0.17 0.048 H2 4.44 2.62 0.21 0.42 0.64 0.20 0.31 0.047 H3 9.27 6.35 0.33 0.99 0.90 0.21 0.27 0.210 S1 18.54 12.15 0.88 2.87 1.45 0.64 0.47 0.095 S2 29.94 19.34 1.17 2.19 4.84 0.64 1.16 0.604 S3 45.41 35.92 1.14 4.37 2.45 0.49 0.64 0.398 D1 34.15 18.81 3.69 6.59 2.04 2.01 0.92 0.083 D2 49.80 19.49 6.05 13.86 4.41 3.54 2.21 0.246 D3 52.95 14.32 5.28 9.64 7.96 8.09 5.79 1.869 Table 6.21. FTP Winter Emission Rates of the PAH Compounds Lumped into Groups ( Naphthalene included)

Sample Sum PAH Group 0 Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7  mg/ mi L2 4.45 1.46 1.24 0.056 0.130 0.613 0.302 0.634 0.0047 ML2 25.30 10.58 10.75 0.291 0.978 1.726 0.354 0.569 0.0539 ML1 10.01 4.09 2.88 0.169 0.370 1.059 0.405 1.024 0.0144 M3 18.93 5.25 7.22 0.312 1.132 2.590 0.829 1.578 0.0173 M2 16.75 6.52 5.60 0.237 0.349 2.543 0.340 1.080 0.0810 M1 23.54 8.45 8.69 0.452 1.273 2.606 0.685 1.343 0.0360 H1 75.71 36.83 25.00 1.102 2.532 5.240 1.131 3.199 0.6700 S3 19.61 8.19 6.97 0.345 1.147 1.905 0.419 0.607 0.0254 S2 39.26 14.94 15.35 0.627 2.500 4.228 0.658 0.886 0.0668 S1 170.96 66.54 64.77 2.539 10.575 18.020 2.386 4.726 1.4052 D5 7.87 0.81 2.04 0.575 1.754 1.462 0.716 0.506 0.0174 D4 12.12 3.12 3.91 0.681 1.869 1.416 0.479 0.491 0.1537 D3 21.79 4.60 7.59 1.519 3.985 2.198 1.162 0.593 0.1435 D2 42.55 5.07 14.77 3.768 10.776 4.558 2.783 0.702 0.1230 D1 58.36 10.79 19.98 4.975 12.046 5.903 3.151 1.211 0.3005 95 Table 6.22. Percent of Total Summer FTP PAH Emitted in Each Group Sample Group1 Group2 Group3 Group4 Group5 Group6 Group7  % of total PAH without naphthalene L1 64.80 4.52 9.03 6.29 6.51 8.04 0.81 L2 67.63 5.70 6.74 6.65 5.58 7.17 0.53 L3 65.92 6.17 7.23 7.62 5.81 6.56 0.68 MI 75.52 3.61 7.43 5.94 3.39 2.91 1.19 M2 72.96 4.32 8.20 6.24 3.43 4.44 0.40 M3 70.77 4.07 10.33 8.34 3.08 2.72 0.69 H1 73.94 3.42 10.77 8.68 1.12 1.60 0.46 H2 58.99 4.80 9.43 14.39 4.45 6.88 1.06 H3 68.58 3.58 10.68 9.75 2.24 2.91 2.26 S1 65.53 4.72 15.49 7.80 3.44 2.51 0.51 S2 64.61 3.90 7.31 16.16 2.14 3.87 2.02 S3 79.10 2.50 9.62 5.40 1.09 1.41 0.88 D1 55.09 10.81 19.29 5.98 5.89 2.71 0.24 D2 39.14 12.16 27.83 8.85 7.10 4.43 0.49 D3 27.04 9.97 18.21 15.03 15.28 10.93 3.53 Table 6.23. Percent of Total Winter PAH Emitted in Each Group Sample Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 % of total PAH ( without naphthalene) L2 41.68 1.89 4.36 20.53 10.12 21.26 0.156 ML2 73.03 1.98 6.64 11.72 2.40 3.86 0.366 ML1 48.62 2.85 6.25 17.89 6.85 17.29 0.244 M3 52.78 2.28 8.28 18.94 6.06 11.54 0.127 M2 54.75 2.31 3.41 24.86 3.32 10.56 0.792 M1 57.62 3.00 8.44 17.27 4.54 8.90 0.239 H1 64.31 2.83 6.51 13.48 2.91 8.23 1.723 S3 61.06 3.02 10.04 16.67 3.67 5.32 0.222 S2 63.13 2.58 10.28 17.38 2.71 3.64 0.275 S1 62.03 2.43 10.13 17.26 2.29 4.53 1.346 D5 28.83 8.14 24.81 20.69 10.13 7.15 0.246 D4 43.47 7.56 20.76 15.73 5.32 5.46 1.707 D3 44.14 8.84 23.19 12.79 6.76 3.45 0.835 D2 39.41 10.05 28.75 12.16 7.43 1.87 0.328 D1 42.01 10.46 25.32 12.41 6.62 2.55 0.632 96 Table 6.24. Percent of Sumer PAH in Each Group by FTP Phase ( without naphthalene)

Category Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7  % of total PAH  Average Phase 1 L 79.7 4.23 7.23 4.40 1.89 2.15 0.38 Average Phase 2 L 47.0 5.97 8.90 11.34 11.72 14.20 0.91 Average Phase 3 L 61.0 9.57 6.08 5.29 7.33 9.40 1.29 Average Phase 1 M 78.9 3.39 8.83 5.64 1.38 1.11 0.75 Average Phase 2 M 56.7 4.96 10.91 11.75 7.37 7.57 0.71 Average Phase 3 M 73.3 4.87 8.73 6.05 3.04 3.34 0.63 Average Phase 1 H 71.9 3.46 9.24 10.00 1.34 2.75 1.29 Average Phase 2 H 65.0 3.84 11.87 11.14 2.97 3.69 1.45 Average Phase 3 H 72.5 3.94 9.83 8.52 1.91 2.44 0.88 Average Phase 1 S 72.2 3.80 8.95 8.14 1.75 3.14 2.06 Average Phase 2 S 70.9 3.14 10.45 10.45 2.05 2.18 0.80 Average Phase 3 S 73.3 3.50 10.29 8.02 1.67 2.16 1.04 Average Phase 1 D 37.3 14.40 24.93 8.32 7.41 6.55 1.11 Average Phase 2 D 31.7 11.71 25.09 12.49 10.86 6.69 1.49 Average Phase 3 D 48.6 7.79 15.76 9.17 10.33 6.24 2.08 Table 6.25. Percent of Winter PAH in Each Group by FTP Phase ( without naphthalene) Category Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 % of total PAH Phase 1 L2 64.25 2.41 5.27 16.68 4.08 7.21 0.09 Phase 2 L2 12.92 1.11 3.68 27.61 17.18 37.28 0.22 Phase 3 L2 47.32 2.36 3.07 12.79 10.58 23.66 0.21 Average Phase 1 ML 74.30 2.53 6.60 11.24 1.54 3.26 0.52 Average Phase 2 ML 57.21 1.86 6.52 16.72 5.69 11.82 0.18 Average Phase 3 ML 68.77 2.46 6.31 9.64 3.97 8.64 0.20 Average Phase 1 M 63.86 2.86 8.37 16.92 2.31 5.26 0.42 Average Phase 2 M 48.20 2.20 5.57 23.31 6.44 13.96 0.31 Average Phase 3 M 57.39 3.23 9.22 14.43 5.21 10.27 0.25 Phase 1 H1 68.12 2.84 6.82 12.65 1.23 4.93 3.42 Phase 2 H1 58.94 2.75 6.25 15.60 4.46 11.43 0.58 Phase 3 H1 76.02 3.27 6.59 5.84 2.19 5.92 0.17 Average Phase 1 S 64.27 2.66 10.40 16.16 1.28 3.26 1.96 Average Phase 2 S 58.59 2.19 10.08 19.23 3.72 5.89 0.31 Average Phase 3 S 66.07 2.93 9.70 14.72 2.15 3.56 0.86 Average Phase 1 D 45.18 10.31 25.21 10.32 5.01 2.87 1.10 Average Phase 2 D 39.17 9.42 25.98 14.36 7.87 2.83 0.37 Average Phase 3 D 40.04 9.91 25.61 13.13 7.05 3.49 0.76 97 Table 6.26. PAH Expressed as a Percent of Summer PM Emissions by Group Sample Group1 Group2 Group3 Group4 Group5 Group6 Group7  Percent of PM Emission Rate

L1 62.6 4.37 8.73 6.08 6.29 7.77 0.78 L2 17.9 1.51 1.79 1.77 1.48 1.90 0.14 L3 16.2 1.52 1.78 1.87 1.43 1.61 0.17 MI 11.7 0.56 1.15 0.92 0.52 0.45 0.18 M2 14.1 0.83 1.58 1.21 0.66 0.86 0.08 M3 21.3 1.22 3.10 2.51 0.92 0.82 0.21 H1 17.0 0.79 2.48 2.00 0.26 0.37 0.11 H2 4.3 0.35 0.69 1.05 0.33 0.50 0.08 H3 6.0 0.31 0.94 0.86 0.20 0.26 0.20 S1 2.4 0.18 0.58 0.29 0.13 0.09 0.02 S2 11.9 0.72 1.35 2.98 0.39 0.71 0.37 S3 19.3 0.61 2.35 1.32 0.27 0.35 0.21 D1 8.8 1.73 3.09 0.96 0.95 0.43 0.04 D2 6.8 2.10 4.81 1.53 1.23 0.77 0.09 D3 0.4 0.13 0.24 0.20 0.20 0.15 0.05 Table 6.27. PAH Expressed as a Percent of Winter PM Emissions by Group Sample Group 0 Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7  Percent of PM Emission Rate L2 20.42 17.34 0.79 1.81 8.54 4.21 8.85 0.065 ML2 49.81 50.64 1.37 4.60 8.13 1.67 2.68 0.254 ML1 11.59 8.15 0.48 1.05 3.00 1.15 2.90 0.041 M3 10.46 14.38 0.62 2.26 5.16 1.65 3.14 0.034 M2 11.94 10.27 0.43 0.64 4.66 0.62 1.98 0.149 M1 10.65 10.96 0.57 1.60 3.28 0.86 1.69 0.045 H1 17.32 11.76 0.52 1.19 2.46 0.53 1.50 0.315 S3 4.07 3.47 0.17 0.57 0.95 0.21 0.30 0.013 S2 2.48 2.55 0.10 0.42 0.70 0.11 0.15 0.011 S1 6.09 5.93 0.23 0.97 1.65 0.22 0.43 0.129 D5 0.23 0.59 0.17 0.51 0.42 0.21 0.15 0.005 D4 0.73 0.92 0.16 0.44 0.33 0.11 0.12 0.036 D3 0.86 1.42 0.28 0.75 0.41 0.22 0.11 0.027 D2 0.81 2.35 0.60 1.72 0.73 0.44 0.11 0.020 D1 1.27 2.36 0.59 1.42 0.70 0.37 0.14 0.035 PAH hazardous air pollutants. The EPA has been constructing emissions inventories for 98 hazardous air pollutants ( HAPs). Polycyclic organic matter ( POM) is on the Office of Air Quality Planning and Standards ( OAQPS) list of 40 priority HAPs. There are a large number of compounds that qualify as POM. EPA has recognized that it is not feasible to inventory all of these compounds, and has recommended that attention be focused on three options. The first option is to inventory the sum of the seven PAHs ( 7 PAH) that have been determined by the International Agency for Research on Cancer ( IARC) to be animal carcinogens. These are benz( a) anthracene, benzo( a) pyrene, benzo( b) fluoranthene, benzo( k) fluoranthene, chrysene, dibenz( a, h) anthracene, and indeno( 1,2,3 cd) pyrene. The second option is to expand this list to 16 compounds ( 16 PAH) by including acenaphthene, acenaphthylene, anthracene, benzo( ghi) perylene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene. The third option is to use extractable organic matter ( EOM) as a surrogate for the POM. All of these compounds were measured in this study, although benzo( b) fluoranthene was not separated from either benzo( k) fluoranthene or benzo( j) fluoranthene. Thus, the 7 PAH sum from this study includes benzo( j) fluoranthene. EOM was not determined in this study, however, OC as measured by the TOR method is similar to the EOM. Table 6.28 lists the 7 PAH, 16 PAH and OC determined for the winter study. Data are not summarized for the summer study due to the lack of naphthalene data and the problems with some of the OC measurements. Correlations were run between the three classes, both including and excluding the diesels, and including each phase of the FTP rather than the composite FTP given in the Table. Not surprisingly, correlations were low.

Table 6.28. Winter FTP Emission Rates of HAP Classifications Sample 7 PAH mg/ mi 16 PAH mg/ mi OC mg/ mi L2 0.0234 11.78 5.7 ML2 0.2905 44.64 12.5 ML1 0.0163 10.27 13.7 M2 0.0398 19.10 19.9 M3 0.6763 87.64 27.8 M1 0.0096 2.25 55.4 H1 0.1121 4.78 64.1 S3 0.1028 6.80 158.2 S1 0.0916 8.83 431.7 S2 0.2184 16.17 455.1 D4 0.0038 2.59 47.5 D3 0.0344 12.57 57.8 D5 0.0087 5.93 142.2 D2 0.0110 8.92 152.6 D1 0.0445 9.82 259.6 Steranes/ hopanes. It has been suggested that steranes and hopanes make good marker compounds for mobile source PM, and that the emission rates for gasoline and diesel 99 vehicles may be different enough that their PM emissions can be distinguished from each other ( Rogge et al., 1993). Steranes and hopanes were measured in the same sample extracts as the PAHs. Thus, their emission rates are for the same composite samples as the PAHs. Table 6.29 lists the individual compounds that were measured and gives the average uncertainty for all tests for the composite FTP. Average uncertainties were lower for the winter measurements compared to the summer measurements. The individual uncertainties tended to increase as the concentration increased.

Table 6.30 gives the average FTP emission rates of each compound for the summer. Missing data indicate that the emission rate for the compound was less than the measurement uncertainty. Emission rates are very low. The average ratio of the emission rate to the uncertainty in the rate for the reported measurements ranged from a high of 5.5 for sitostane to 1.9 for trisnorhopane 1. Several of the compound's emission rates averaged only two to three times the uncertainty. Thus, it should be recognized that significant errors are probable in the rates. The next to last row of the table gives the sum of the emission rates of the measured compounds, followed by its percentage of the PM emission rate. Thus, it is seen that the measured compounds accounted for 0.78% of the PM emissions for the low emitters, but only 0.086% of the PM for the diesels.

Table 6.31 gives the average FTP emission rates for the winter. A larger portion of the measurements in the winter were below the measurement uncertainty, resulting in more non detectables than in the summer. The average ratio of emission rate to uncertainty in the emission rate ranged from a high of 6.1 for diasterane 1 to 2.4 for cholestane 2. The sum of the emission rates for each category is given in the next to last row of the table, followed by its percentage of the total PM emission rate. Winter hopane and sterane emissions constituted a lower percentage of the PM than during the summer, by factors of two to four. This difference can not be attributed entirely to the greater number of non detectable compounds in the winter. The cause of the reduction is not known.

Figures 6.28 and 6.29 compare the summer emission rates of the hopanes and steranes for each category. The pattern of emissions is very similar with the exceptions of norhopane 2, hopane 2 and hopane 3 which were not detectable for some emitter categories. Figure 6.30 shows the similar comparison for the winter. The low and medium low emitters were excluded from this comparison because of the large number of non detectable compounds. Also, the five highest molecular weight compounds were omitted from the comparison since none were detected in the winter. The highest emission rates are for the smokers. Both the diesels and smokers have higher relative emission rates of the lower molecular weight compounds than the medium and high emitters. Overall, it is concluded that these compounds may make excellent tracers for mobile source particulate emissions. However, there is no indication that they can be used to distinguish between diesel and gasoline vehicle PM emissions. It may be that the primary source of these compounds is motor oil. However, no measurements of these species were made in either the fuel or motor oil.

Tables 6.32 through 6.36 give the average emission rates of the hopanes and steranes by FTP phase for each emitter category. Only those rates that were greater than the measurement uncertainty are included in the averages. As expected, many of the 100 compounds show a distinct difference in rates between phases, indicating that profiles used for source apportionment might benefit from using the actual cold start/ stabilized running/ hot start data for a given area rather than using the FTP default weighting.

Table 6.29. Average Uncertainty in Hopane and Sterane Measurements Compound Emission Rate, mg/ mi Summer Winter ergostane 0.00813 0.00106 sitostane 0.00453 0.00151 diasterane 1 0.00725 0.00119 diasterane 2 0.00346 0.00103 cholestane 1 0.00791 0.00193 cholestane 2 0.00368 0.00221 cholestane 3 0.01338 0.00225 trisnorhopane 1 0.00660 0.00089 trisnorhopane 2 0.00413 0.00106 norhopane 1 0.01374 0.00286 norhopane 2 0.00545 0.00209 hopane 1 0.00760 0.00143 hopane 2 0.00445 0.00155 homohopane 1 0.00277 0.00077 homohopane 2 0.00258 0.00077 hopane 3 0.00234 0.00077 bishomohopane 1 0.00299 0.00077 bishomohopane 2 0.00273 0.00077 101 Table 6.30. Summer Average FTP Emission Rates for Hopanes and Steranes Compound Ave L Ave M Ave H Ave S Ave D mg/ mi ergostane 0.0031 0.0050 0.0123 0.0534 0.1168 sitostane 0.0043 0.0054 0.0082 0.0357 0.0874 diasterane 1 0.0012 0.0047 0.0044 0.0336 0.3135 Diasterane 2 0.0014 0.0034 0.0041 0.0257 0.0471 cholestane 1 0.0033 0.0047 0.0089 0.0475 0.1009 cholestane 2 0.0014 0.0042 0.0028 0.0166 0.0355 cholestane 3 0.0027 0.0033 0.0070 0.0452 0.0915 Trisnorhopane 1 0.0016 0.0041 0.0037 0.0173 0.0427 Trisnorhopane 2 0.0010 0.0032 0.0033 0.0130 0.0309 norhopane 1 0.0089 0.0087 0.0145 0.0598 0.1561 norhopane 2 ND 0.0125 ND 0.0053 ND hopane 1 0.0071 0.0080 0.0100 0.0349 0.1074 hopane 2 0.0020 0.0080 0.0036 0.0277 Homohopane 1 0.0035 0.0036 0.0051 0.0148 0.0500 Homohopane 2 0.0023 0.0032 0.0039 0.0106 0.0387 hopane 3 ND 0.0028 ND ND ND Bishomohopane 1 0.0019 0.0023 0.0031 0.0079 0.0284 Bishomohopane 2 0.0016 0.0024 0.0024 0.0054 0.0229 Sum 0.047 0.090 0.094 0.43 1.30 % of PM 0.78 0.37 0.13 0.15 0.086 102 Table 6.31. Winter Average FTP Emission Rates for Hopanes and Steranes Compound L2 Ave ML Ave M H Ave S Ave D mg/ mi Ergostane ND 0.00108 ND ND 0.01064 0.00356 Sitostane ND 0.00201 ND 0.00532 0.03344 0.00994 diasterane 1 ND ND ND 0.00326 0.01493 0.01019 diasterane 2 ND ND ND 0.00179 0.01006 0.00521 cholestane 1 ND 0.00148 0.00214 0.00350 0.02215 0.00998 cholestane 2 ND ND 0.00351 0.00342 0.01343 0.00951 cholestane 3 ND 0.00112 0.00352 0.00328 0.02029 0.00785 trisnorhopane 1 ND 0.00135 0.00188 0.00323 0.00421 0.00395 trisnorhopane 2 ND ND ND ND 0.00486 0.00362 norhopane 1 0.00376 0.00766 0.00939 0.01644 0.02347 0.01965 norhopane 2 0.00641 0.00623 0.01249 0.01623 0.01105 0.01323 hopane 1 0.00427 0.00501 0.00721 0.01203 0.01533 0.01251 hopane 2 ND 0.00372 0.00485 0.00818 0.00719 0.00811 homohopane 1 ND 0.00134 ND ND ND ND homohopane 2 ND ND ND ND ND ND hopane 3 ND ND ND ND ND ND bishomohopane 1 ND ND ND ND ND ND bishomohopane 2 ND ND ND ND ND ND Sum 0.014 0.031 0.045 0.077 0.19 0.12 % of PM 0.20 0.11 0.073 0.036 0.030 0.021 Table 6.32. Average Summer Emission Rates of Hopanes and Steranes by FTP Phase Composite Ergostane sitostane diasterane 1 diasterane 2 Cholestane 1 cholestane 2  mg/ mi  L Phase 1 0.00251 0.00388 0.00183 0.00159 0.00231 0.00115 L Phase 2 0.00304 0.00347 0.00098 0.00133 0.00327 0.00112 L Phase 3 0.00363 0.00594 0.00121 0.00152 0.00401 0.00198 M Phase 1 0.00719 0.00947 0.00618 0.00491 0.00872 0.00344 M Phase 2 0.00495 0.00556 0.00309 0.00325 0.00596 0.00193 M Phase 3 0.00336 0.00386 0.00221 0.00211 0.00474 0.00156 H Phase 1 0.01647 0.01076 0.00881 0.00735 0.01319 0.00415 H Phase 2 0.00981 0.00665 0.00272 0.00251 0.00759 0.00224 H Phase 3 0.01408 0.00919 0.00448 0.00481 0.00834 0.00274 S Phase 1 0.08063 0.05678 0.05444 0.04332 0.07880 0.02625 S Phase 2 0.04075 0.02601 0.02403 0.01812 0.03353 0.01252 S Phase 3 0.05762 0.03859 0.03658 0.02720 0.05090 0.01709 D Phase 1 0.08982 0.06675 0.08096 0.03816 0.07090 0.02550 D Phase 2 0.10828 0.08241 0.33561 0.04590 0.09858 0.03317 D Phase 3 0.15304 0.11239 0.44692 0.05602 0.12788 0.04729 103 Table 6.33. Average Summer Emission Rates of Hopanes and Steranes by FTP Phase Composite cholestane 3 trisnorhopane 1 trisnorhopane 2 norhopane 1 Norhopane 2 hopane 1  mg/ mi  L Phase 1 0.00297 0.00162 0.00115 0.00896 ND 0.00581 L Phase 2 0.00177 ND ND 0.00574 ND 0.00513 L Phase 3 0.00398 0.00183 0.00114 0.01451 ND 0.01166 M Phase 1 0.00622 0.00345 0.00314 0.02076 ND 0.01219 M Phase 2 0.00496 0.00222 0.00210 0.01098 ND 0.00703 M Phase 3 0.00229 0.00142 ND 0.00926 ND 0.00649 H Phase 1 0.01214 0.00506 0.00338 0.01911 ND 0.01249 H Phase 2 0.00503 0.00339 0.00203 0.01196 ND 0.00825 H Phase 3 0.00684 0.00342 0.00219 0.01578 ND 0.01150 S Phase 1 0.07110 0.02698 0.01968 0.09039 0.00616 0.05341 S Phase 2 0.03339 0.01274 0.01002 0.04619 ND 0.02654 S Phase 3 0.04860 0.01877 0.01386 0.06329 ND 0.03715 D Phase 1 0.05213 0.03274 0.02372 0.11069 ND 0.08073 D Phase 2 0.09200 0.03674 0.02845 0.14576 ND 0.10265 D Phase 3 0.12008 0.06138 0.04100 0.20999 ND 0.13661 104 Table 6.34. Average Summer Emission Rates of Hopanes and Steranes by FTP Phase Composite hopane 2 homohopane 1 homohopane 2 hopane 3 Bishomohopane 1 bishomohopane 2  mg/ mi  L Phase 1 ND 0.00285 0.00098 ND 0.00091 ND L Phase 2 ND 0.00256 0.00169 ND 0.00140 0.00138 L Phase 3 0.00293 0.00560 0.00428 ND 0.00358 0.00282 M Phase 1 ND 0.00650 0.00522 ND 0.00372 0.00315 M Phase 2 ND 0.00271 0.00205 ND 0.00160 0.00170 M Phase 3 ND 0.00324 0.00239 ND 0.00113 H Phase 1 ND 0.00619 0.00459 ND 0.00343 0.00270 H Phase 2 ND 0.00402 0.00313 ND 0.00246 0.00190 H Phase 3 ND 0.00619 0.00475 ND 0.00392 0.00319 S Phase 1 0.00555 0.0217 0.0160 ND 0.01225 0.00828 S Phase 2 0.00274 0.0111 0.0079 ND 0.00578 0.00422 S Phase 3 0.00366 0.0169 0.0117 ND 0.00874 0.00560 D Phase 1 ND 0.0412 0.0286 ND 0.0226 0.0195 D Phase 2 ND 0.0474 0.0391 ND 0.0267 0.0219 D Phase 3 ND 0.0615 0.0454 ND 0.0359 0.0274 Table 6.35. Average Winter Emission Rates of Steranes by FTP Phase Composite Ergostane sitostane diasterane 1 diasterane 2 cholestane 1 Cholestane 2 cholestane 3  mg/ mi

ML Phase 1 ND ND ND ND ND ND ND ML Phase 2 ND ND ND ND ND ND ND ML Phase 3 0.004 0.0074 0.0030 0.0029 0.0055 0.0022 0.0041 M Phase 1 ND ND ND ND ND ND ND M Phase 2 ND ND ND ND ND ND ND M Phase 3 ND ND ND ND 0.0082 0.013 0.014 H Phase 1 ND 0.024 0.015 0.0080 0.016 0.015 0.015 H Phase 2 ND ND ND ND ND ND ND H Phase 3 ND ND ND ND ND ND ND S Phase 1 0.030 0.067 0.037 0.026 0.071 0.033 0.061 S Phase 2 0.011 0.025 0.013 0.0089 0.016 0.012 0.016 S Phase 3 0.0064 0.025 0.016 0.010 0.015 0.010 0.020 D Phase 1 0.011 0.023 0.022 0.010 0.025 0.013 0.017 D Phase 2 ND 0.015 0.0098 0.0054 0.0079 0.015 0.010 D Phase 3 0.0097 0.023 0.012 0.0081 0.012 0.0098 0.014 105 Table 6.36. Average Winter Emission Rates of Hopanes by FTP Phase Composite Trisnorhopane 1 Trisnorhopane 2 norhopane 1 norhopane 2 hopane 1 hopane 2  mg/ mi

ML Phase 1 0.0030 ND 0.0076 0.0076 0.0052 0.0038 ML Phase 2 ND ND 0.0069 0.0066 0.0044 0.0043 ML Phase 3 0.0027 0.0025 0.0092 0.0045 0.0060 0.0026 M Phase 1 0.0027 ND 0.0084 0.0094 0.0062 0.0054 M Phase 2 0.0028 0.0017 0.0087 0.012 0.0065 0.0063 M Phase 3 0.0047 0.0025 0.011 0.016 0.0094 0.0024 H Phase 1 0.0062 0.0038 0.025 0.022 0.018 0.0025 H Phase 2 0.0043 ND 0.016 0.017 0.012 0.012 H Phase 3 ND ND 0.011 0.011 0.0077 0.0072 S Phase 1 0.0048 0.0078 0.016 0.0082 0.011 0.0056 S Phase 2 0.0042 0.0043 0.027 0.014 0.017 0.0094 S Phase 3 0.0037 0.0038 0.022 0.0072 0.015 0.0041 D Phase 1 0.0052 0.0060 0.026 0.0087 0.016 0.0036 D Phase 2 0.0043 0.0031 0.017 0.015 0.011 0.0092 D Phase 3 0.0039 0.0037 0.020 0.014 0.013 0.0094 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 7. Emissions Inventory It is intended that the data presented in this report be used by state and federal agencies to improve PM emission inventory estimates. A complete examination of the PM emission inventory is beyond the scope of this report. However, a simple, preliminary estimation of the light duty exhaust emissions inventory for the Colorado Front Range area was made using the following assumptions. First, it is assumed that the FTP weighting of cold starts, hot starts, and hot stabilized running represents actual in use activity data for the region. Second, we assume that the FTP is an adequate representation of driving in the region, even though it is well known that it omits some driving conditions that may increase particulate emissions. Third, it is assumed that the smoking gasoline vehicle VMT is 0.1% of the total. This is based on a limited visual observation survey of smoking vehicles done for this program. Fourth, we assume that the vehicles tested in this program represent an unbiased sample with an adequate population to provide reasonable average emission rates. All of these assumptions could result in low estimates of real world PM emissions.

Table 7.1 gives the average PM emission rates for the summer period used in this exercise. No distinction was made between truck and car PM emission rates, since the population of vehicles tested was judged to be too small to subdivide further. The averages do, however, contain approximately 30% light duty trucks. Since only 9 smoking vehicles were tested in the summer, the average of the summer and winter indoor smoking vehicle emission rates ( 300 mg/ mi) was used for this category. Also, both summer and winter indoor diesel tests were combined to obtain an average light duty diesel emission rate of 637 mg/ mi for 1972 80 vehicles and 326 mg/ mi for 1981 85 vehicles. No newer lightduty diesels were tested. Newer diesel vehicles tested in the summer were in the heavyduty classification. Therefore an emission rate of 80 and 100 mg/ mi was assumed for the 1991 96 and 1986 1990 diesel vehicles, respectively. The winter PM emission rates are given in Table 7.2. Since there was little difference between indoor and outdoor diesel PM emission rates, the same average rate was used for the winter as the summer.

Table 7.1. Summer PM Emission Rates Vehicle Type 1991 96 1986 90 1981 85 1972 1980 PM Emission Rate, mg/ mi LDGV 2.8 44.4 47.4 95.5 LDGT1 2.8 44.4 47.4 95.5 LDGT2 2.8 44.4 47.4 95.5 LDDV 80 100 579 637 LDDT 80 100 326 637 LDGV Smoker 330 330 330 330 137 Table 7.2. Winter PM Emission Rates Vehicle Type 1991 96 1986 90 1981 85 1972 1980 PM Emission Rate, mg/ mi LDGV 24.9 28.5 48.2 82.6 LDGT1 24.9 28.5 48.2 82.6 LDGT2 24.9 28.5 48.2 82.6 LDDV 80 100 579 637 LDDT 80 100 326 637 LDGV Smoker 330 330 330 330 Table 7.3 gives the Colorado Front Range area daily vehicle miles traveled ( VMT) for each category. With the exception of the smoking vehicle VMT, these data were supplied by the State of Colorado. Smoking vehicle VMT was arbitrarily assigned to the two oldest year categories, since most smoking vehicles are relatively old. Multiplying the emission rates and the daily VMT gives the tons of PM per day in each of the categories. Results for the summer and winter are given in Tables 7.4 and 7.5.

Table 7.3. Front Range Daily VMT by Vehicle Category.

Vehicle Type Daily VMT/ 1000 1991 96 fraction 1986 90 fraction 1981 85 fraction 1972 80 fraction LDGV 29,308 0.501 0.316 0.137 0.046 LDGT1 9,883 0.424 0.323 0.162 0.091 LDGT2 4,936 0.373 0.323 0.184 0.12 LDDV 185 0.122 0.057 0.651 0.169 LDDT 114 0.131 0.114 0.638 0.117 LDGV Smoker 400 0.0 0.0 0.5 0.5 138 Table 7.4. Front Range Summer PM Emissions by Vehicle Category.

Vehicle type 1991 96 1986 90 1981 85 1972 80 Total Metric tons/ day LDGV 0.041 0.41 0.19 0.13 0.77 LDGT1 0.012 0.14 0.076 0.086 0.32 LDGT2 0.005 0.071 0.043 0.057 0.18 LDDV 0.002 0.001 0.070 0.020 0.092 LDDT 0.001 0.001 0.024 0.008 0.035 LDGV Smoker 0 0 0.066 0.066 0.13 Total 1.53 Table 7.5. Front Range Winter PM Emissions by Vehicle Category.

Vehicle type 1991 96 1986 90 1981 85 1972 80 Total Metric tons/ day LDGV 0.37 0.26 0.19 0.11 0.93 LDGT1 0.10 0.091 0.077 0.074 0.35 LDGT2 0.046 0.045 0.044 0.049 0.18 LDDV 0.002 0.001 0.070 0.020 0.09 LDDT 0.001 0.001 0.023 0.008 0.035 LDGV smoker 0 0 0.066 0.066 0.132 Total 1.72 A total of 1.53 and 1.72 tons per day of PM 10 is estimated to be emitted in this area in the summer and winter, respectively. For the summer the largest contributing category ( 26.8%) is the 1986 90 light duty gasoline vehicles. All 1991 96 light duty cars and trucks combined account for only 3.8% of the total. Smoking vehicles, even at an estimated 0.1% of the VMT contribute 8.5% of the total. Since this number is highly uncertain, the smoking vehicle contribution may be significantly larger. The small number of light duty diesel cars and trucks also account for 8.3% of the total. For the winter, the largest single category is the 1990 96 vehicles, which contribute 21.2% of the total PM 10. This value is also highly uncertain since the average emission rate for this category comes from only nine vehicles, two of which had very high emission rates. The whole fleet average PM 10 emission rate for the summer and winter, respectively, was 33.9 and 38.4 mg/ mi Given the number of assumptions that have gone into these estimates it is obvious that significant errors are possible. Despite that, the overall estimate is probably better than that currently used since the database is greatly improved. In addition, the exercise is useful in pointing towards areas where improved data are needed. 139 8. Conclusions The major conclusions from this study are:

  Late model ( 1991 96) light duty gasoline vehicles have low exhaust PM emission rates under FTP conditions.   Average exhaust PM emission rates are higher for older model year vehicles than for late model year vehicles.   PM emission rates are significantly higher in the cold start ( phase 1) portion of the FTP than in the hot stabilized or hot start portions ( phases 2 and 3).   Exhaust PM emission rates increase at low temperatures. As expected, the increase is for FTP phase 1 only.   An observed decrease in the average PM emission rate under FTP conditions between the summer and the winter is consistent with previously reported effects of oxygenated fuels.   Average PM emission rates are similar for the FTP and the IM240, suggesting that the IM240 can be used to estimate fleet average PM emission rates.   Impactor size distributions show that more than 91% of the PM 10 is smaller than PM 2.5. Mass median diameters ranged from 0.12 µ m to 0.18 µ m.   Continuous particle counts show that particle emission rates are highly variable during FTP tests, with the highest rates occurring during cold start and accelerations.   Most of the particulate mass is carbonaceous matter. The average fraction of carbonaceous matter that is organic is higher for gasoline vehicles than diesel vehicles.   Sulfate emissions averaged less than 1 mg/ mi for the gasoline fleet, but were higher for the diesel fleet.   Gasoline and diesel vehicles emit the same PAH compounds. However, there are differences in the relative emission rates of some of the compounds. These differences may be useful in source apportionment studies for separating diesel from gasoline PM emissions.   Gasoline and diesel vehicles emit the same hopane and sterane compounds. There is little difference in the relative emission rates. Therefore, these species are not useful in separating diesel and gasoline PM emissions in source apportionment studies.   The fleet average PM emission rate for the Colorado Front Range was estimated at 33.9 mg/ mi for the summer and 38.4 mg/ mi for the winter. The largest uncertainties are in the number of in use smoking vehicles and the winter PM emission rate for latemodel gasoline vehicles. 140 Acknowledgments This program would not have been possible without the assistance of the following individuals to whom we are indebted. Deborah Kielian from the City and County of Denver assisted in recruiting smoking vehicles. Phil Gee, Bill Miron, Sherry Larson, Zina Washington, and Dawn Mirabile from the CDPHE helping recruit vehicles and provided other assistance. Peter Groblicki from GM calibrated the electrical aerosol analyzer for use in this study. Jerrold Faircloth, Versal Mason, and Michael Wheeler helped operate the EPA emission test site. Judith C. Chow, Clifton L. Frazier, Eric M. Fujita, Terry Hays, Steven D. Kohl, John Sagebiel, Ewa Uberna, John G. Watson and Barbara Zielinska at the Desert Research Institute contributed to the sample analysis and validation. We also thank the Coordinating Research Council, the NFRAQS program, the Department of Energy, and Total Petroleum for their financial support of this project.

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