People spend a significant amount of time in traffic, during which they are exposed to high levels of air pollution. Very few studies measured acute health effects after real life exposure in traffic. The large TRAVEL study assessed exposure and related acute health effects of people commuting by bicycle, car, and bus.
Exposure to and inhalation of ultrafine particles, particulate matter (PM10), PM2.5, and soot were measured during 2-hour commutes in Arnhem, a medium-sized city in the Netherlands. Commuting took place from 8 till 10 am. Before, immediately after, and 6 hours after exposure, we measured lung function, airway resistance, and nitric oxide in exhaled air as a marker of lung inflammation.
During the 47 measurement days, we collected 352 pre- and post-health measurements of 34 healthy, nonsmoking, adult volunteers. Exposures differed by mode of transport, route, and fuel type. Using mixed model analysis, we found negative associations between ultrafines and FEV1, and positive associations between ultrafines and airway resistance, and exhaled NO. Ambient NO2, but not ambient ozone, was significantly associated with increased exhaled NO levels.
Two hour in-traffic exposures to particle number counts were associated with decrease in FEV1, increase in airway resistance, and increase in exhaled NO, a marker of airway inflammation. Effects of exposure in traffic to PM2.5, PM10, and soot were not consistently associated with respiratory health outcomes.