Figure 2

EBC outcome measurements before and after breathing either HEPA-filtered or unfiltered air during car rides. EBC nitrite (a), nitrite + nitrate (b), and MDA (c) at pre-exposure, immediately post-exposure, and 6 and 24 hr post-exposure with HEPA filtered breathing air (dashed line) or unfiltered breathing air (solid line). N = 20 for most data points, with missing single data points at some 6 and 24 hours (N = 19) *indicates significance at p = 0.02 for exposure effects comparing change from baseline for unfiltered rides to change from baseline for filtered rides.