Table 3 Estimated% difference (95% CI) in EBC nitrite, nitrite + nitrate, and malondialdehyde (MDA) associated with interquartile range change relative to the median, adjusted for pre-exposure level, in particle number concentration (cm ⁻¹ ,PN) and PM2.5 inside the respirator for all car rides

Nitrite

PN

0 hr

99.4%

(32.1% to 166.7%)*

6 hr

22.3%

(−21.9% to 66.5%)

24 hr

7.1%

(−16.2% to 29.8%)

PM2.5

0 hr

27.6%

(−27.3% to 82.4%)

6 hr

13.2%

(−18.6% to 45.0%)

24 hr

−1.9%

(−10.0% to 6.2%)

Nitrite + Nitrate

PN

0 hr

75.7%

(21.5% to 130.0%)*

6 hr

62.9%

(−35.5% to 160.3%)

24 hr

33.5%

(−18.6% to 85.2%)

PM2.5

0 hr

26.4%

(−13.7% to 66.5%)

6 hr

8.9%

(−61.0% to 78.8%)

24 hr

7.8%

(−33.0% to 48.6%)

MDA

PN

0 hr

11.3%

(−16.2% to 37.3%)

6 hr

0.3%

(−43.2% to 42.7%)

24 hr

15.1%

(−16.8% to 47.1%)

PM2.5

0 hr

−1.4%

(−20.6% to 17.9%)

6 hr

3.8%

(−27.0% to 34.5%)

24 hr

1.1%

(−24.3% to 26.6%)