Skip to main content

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.