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

EBC biomarker	Pollutant**	Time pt.	% Response/IQR increase
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%)

*p < 0.01 for change from baseline.

**Inter-quartile ranges: PN = 36,392, PM2.5 = 5.25, BC = 4.66.