Table 2.

Epidemiological studies of air pollution exposure in traffic.

Study population	Design	Main findings	Comments	Reference
Sixty mild to moderate asthmatic adults in London	Exposure during 2 hr walking in OS or HP, pre/postexposure physiologic measurements: median PM2.5 concentration, 28 (OS) vs. 11 μg/m3 (HP); median EC, 7.5 vs. 1.3 μg/m3; median UFP, 63,700 vs. 18,300 particles/cm3	Asymptomatic decrease in lung function and increase in inflammation after walking in OS compared with HP; changes most consistently associated with EC and UFP; per 1-μg/m3 significant increase in EC decrement in lung function of ~ 1% decrement in lung function and ~ 2% increase in exhaled NO (inflammation)	OS has diesel traffic only	McCreanor et al. 2007
Subjects (n = 691) with MI in Augsburg	Case–crossover study comparing the frequency of participation in traffic in the hours before the MI and a control period (24–72 hr before MI)	RR = 2.92 for participation in traffic in the hour before the MI; increased risk found for all transport means (car, bicycle, public transport)	May be stressors other than air pollution	Peters et al. 2004
Nine healthy young U.S. policemen	Physiologic measurements before and after 8-hr work shift; average in-vehicle PM2.5, 24 μg/m3	Significant increases of heart rate variability, ectopic beats, blood inflammatory and coagulation markers, and red blood cell volume; per 10-μg/m3 PM2.5 effect on C-reactive protein, +32%; neutrophils, +6%; von Willebrand factor, +12%; and ectopic beats, +20%.		Riediker et al. 2004
Twelve healthy young subjects	Physiologic measurements before and after 1-hr cycling trip from city center to university in Utrecht	Statistically nonsignificant 1–3% decrements in lung function per 105/m soot concentration and a 15% increase in exhaled NO per 38,000 particles/cm3		Strak et al. 2010

Abbreviations: EC, elemental carbon; HP, Hyde Park; MI, myocardial infarction; NO, nitric oxide; OS, Oxford Street; RR, relative risk; UFP, ultrafine particle count.