EOHSI

Diesel exhaust is produced by many trucks, buses and trains.

Traffic-related air pollution can make asthma worse. A recent study at the Center for Environmental Exposures and Disease (CEED) found that diesel exhaust causes airway stress in people with asthma.

Traffic-related pollution has been associated with asthma attacks, but it’s not clear how this pollution makes asthma worse. Scientists try to answer this question by doing experiments with diesel exhaust, a major type of traffic-related pollution. Better understanding of how pollution makes asthma worse can lead to better ways to prevent or treat asthma.

In this study, sixteen volunteers with mild to moderate asthma participated in a diesel exhaust exposure study. The volunteers were exposed to clean, filtered air for 1 hour on one day and air with diluted diesel exhaust for 1 hour on another day.

Left: Nitrite levels in breath samples, before (pre), immediately after (post), and 4 and 24 hours after exposure to air with diluted diesel exhaust compared to clean air control. Right: Forced expiratory volume in 1 second (FEV-1) before (baseline), immediately after (post), and 4 and 24 hours after a 1-hour exposure to air with diluted diesel exhaust compared to clean air control.

After exposure to diluted diesel exhaust, we found a temporary decrease in the amount of air the participants could blow out in one second (forced expiratory volume in 1 second, or FEV-1), a standard asthma test. We also found an increase in airway constriction in another asthma test. The volunteers also had higher levels of nitrite in breath samples immediately after the diesel exhaust exposure, indicating that oxidative stress may cause these respiratory effects.

Next Steps: We are extending these studies to include people with asthma living near congested roadways and routes with high diesel truck traffic, and studies of how anti-oxidants in foods might combat the effects of traffic air pollution.

Read the published research: Hussain S, Laumbach R, Coleman J, Youseff H, Kelly-McNeil K, Ohman-Strickland P, et al. Controlled Exposure to Diesel Exhaust Causes Increased Nitrite in Exhaled Breath Condensate among Subjects with Asthma. Journal of Occupational and Environmental Medicine. 2012;54(10):1186-91. PMCID: PMC4443752.

Click here to learn about currently ongoing studies at EOHSI.

This research was funded in part by the National Institute of Environmental Health Sciences (NIEHS) through the Center for Environmental Exposures and Disease at EOHSI (NIH-NIEHS P30 ES005022) and USEPA STAR Grant R832144.

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