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Table 1 Subject information and subject-level average exposure of PB-PAH (ng/m 3 ) across all the sampling sessions

From: Modeling personal particle-bound polycyclic aromatic hydrocarbon (pb-pah) exposure in human subjects in Southern California

   N (%) Arithmetic mean(STD a ) Geometric mean (STD a ) P-value b Range
Overall   28 (100.0%) 11.0(6.2) 9.3(1.9)   1.7-29.9
Complete days of measurements (≥6 h/day) 1 day 6 (21.4%) 8.1(6.5) 5.7(2.7) 0.17 1.7-15.4
2-5 days 8 (28.6%) 13.5(7.3) 12.2(1.6)   6.6-29.9
6-9 days 8 (28.6%) 11.3(6.7) 9.9(1.7)   4.6-24.3
≥10 days 6 (21.4%) 10.2(3.2) 9.8(1.5)   4.4-13.2
Age 18-29 15 (53.6%) 10.5(6.9) 8.4(2.1) 0.40 1.7-29.9
30-38 13 (46.4%) 11.5(5.6) 10.4(1.7)   4.4-24.3
Race/Ethnicity Asian 6 (21.4%) 11.7(4.7) 10.8(1.7) 0.42 4.4-15.8
Hispanic 13 (46.4%) 10.6(7.3) 8.4(2.2)   1.7-29.9
Non-Hispanic White 6 (21.4%) 13.4(6.2) 12.4(1.6)   6.6-24.3
Other 3 (10.7%) 6.2(1.6) 6.2(1.3)   4.6-7.7
Income Low (<$50 k/year) 15 (53.6%) 10.7(5.6) 9.3 (1.9) 1.00 1.7-24.3
High (≥$50 k/year) 13 (46.4%) 11.3(7.2) 9.3 (2.0)   2.4-29.9
Speaking English at home No 11 (39.3%) 12.5(4.9) 11.9(1.4) 0.11 6.6-24.3
Yes 17 (60.7%) 10.0(7.0) 8.0(2.1)   1.7-29.9
Worker No 11 (39.3%) 9.2(5.0) 7.6(2.1) 0.19 1.7-15.8
Yes 17 (60.7%) 12.2(6.8) 10.6(1.8)   2.8-29.9
Had work-related exposure to traffic pollutantsc No 23(82.1%) 10.1(6.0) 8.5(1.9) 0.10 1.7-29.9
Yes 5(17.9%) 15.2(6.1) 14.3(1.5)   7.7-24.3
Indoor time <90.7% 14 (50%) 11.9(7.9) 9.5(2.2) 0.91 1.7-29.9
≥90.7% 14 (50%) 10.1(4.1) 9.2(1.7)   2.4-16.3
In-vehicle time <3.8% 14 (50%) 9.3(5.2) 7.6(2.1) 0.11 1.7-16.3
≥3.8% 14 (50%) 12.6(6.9) 11.3(1.6)   4.6-29.9
Weekday <72.9% 14 (50%) 9.9(7.5) 7.6(2.2) 0.09 1.7-29.9
≥72.9% 14 (50%) 12.1(4.7) 11.4(1.4)   6.6-24.3
Daytime <54.1% 14 (50%) 10.7(6.8) 9.1(1.9) 0.85 2.4-29.9
≥54.1% 14 (50%) 11.3(5.9) 9.6(2.0)   1.7-24.3
Time in rush hour <21.6% 14 (50%) 10.8(4.1) 10.1(1.5) 0.54 4.4-16.3
≥21.6% 14 (50%) 11.2(8.0) 8.6(1.3)   1.7-29.9
GPS speed <1.9 km/h 14 (50%) 9.1(4.9) 7.6(2.1) 0.10 1.7-16.3
≥1.9 km/h 14 (50%) 12.8(7.1) 11.4(1.7)   4.6-29.9
Elevation <26.6 m 14 (50%) 12.0(5.3) 10.6(1.9) 0.30 1.7-24.3
≥26.6 m 14 (50%) 10.0(7.1) 8.2(2.0)   2.4-29.9
Length-weighted AADT within 500 m <23172 vehicles/day 14 (50%) 10.2(7.1) 8.1(2.1) 0.28 1.7-29.9
≥23172 vehicles/day 14 (50%) 11.8(5.4) 10.6(1.7)   2.8-24.3
Traffic density within 300 m <79891 vehicles per day*km/km2 14 (50%) 8.4(4.6) 7.0(2.0) 0.02 1.7-15.4
≥79891 vehicles per day*km/km2 14 (50%) 13.5(6.7) 12.3(1.6)   6.3-29.9
Ambient temperature <20.6 °C 14 (50%) 9.9(5.9) 8.3(1.9) 0.37 2.4-24.3
≥20.6 °C 14 (50%) 12.1(6.6) 10.4(1.9)   1.7-29.9
Ambient relative humidity <63.7% 14 (50%) 13.9(7.0) 12.2(1.8) 0.02 2.8-29.9
≥63.7% 14 (50%) 8.1(3.9) 7.1(1.9)   1.7-13.2
Wind speed <4.3 m/s 14 (50%) 11.2(6.6) 9.7(1.8) 0.75 2.4-29.9
  ≥4.3 m/s 14 (50%) 10.8(6.2) 8.9(2.1)   1.7-24.3
  1. a Standard deviation.
  2. b p-value for the difference in geometric means stratified by different sub-groups.
  3. cWork-related exposure includes working around parking garage, kiosk, auto shop, buses, trucks, or heavy traffic, or driving a car/bus/truck during the work.