Drivers Exposed to 29 Times More Air Pollution While Stopped at Red Lights, Study Finds

Red Light Are Health Hazard for Drivers
The World Health Organization recently linked air pollution to 7 million premature deaths in 2012 alone. Gareth Williams/Flickr

Driving with the windows down on a clear blue day may feel refreshing. Really, though, that breeze is toxic.

According to new research, you're dosing yourself with high levels of harmful air pollution every time you stop at a red light. Braking at traffic lights, and then accelerating when they turn green, makes up only around 2 percent of the time a driver spends in the car. Yet that scant amount of time makes up fully 25 percent of a driver's total air pollution exposure, according to a study published Thursday in the journal Atmospheric Environment. The concentration of pollution particles in these moments are as much as 29 times higher than concentrations seen while the car is simply cruising, the study found.

"Our time spent traveling in cars has remained fairly constant during the past decade despite the efforts to reduce it, and with more cars than ever joining the roads, we are being exposed to increasing levels of air pollution as we undertake our daily commutes," Prashant Kumar, the study's lead author and a senior lecturer at the University of Surrey focusing on urban air quality and environmental engineering, said in a press release.

Kumar notes that keeping car windows shut and fans off at red lights helps to limit exposure, since fans suck in the outdoor air. It's also a good idea to try to increase the distance between one's vehicle and the car in front whenever possible, to reduce how much of that car's exhaust winds up in your airspace.

He also has advice for people on the sidewalk. "Pedestrians regularly crossing such routes should consider whether there might be other paths less dependent on traffic light crossings. Local transport agencies could also help by synchronizing traffic signals to reduce waiting time and consider alternative traffic management systems such as flyovers."

This news doesn't bode well for the cyclist who rides with traffic at rush hour, since there is virtually no way to create a barrier between a cyclist and a nearby car's tailpipe. But a recent study found that bike lanes that allow cyclists to ride separately from the flow of traffic significantly cut down on riders' air pollution exposure.

The World Health Organization recently linked air pollution to 7 million premature deaths in 2012 alone, which amounts to one in every eight people who died that year. Cardiovascular disease, asthma and cancer, among a host of other ailments, have been linked to chronic air pollution exposure. Air pollution has also been linked to adverse pregnancy outcomes, such as early birth and low birth weight. And a recent study concluded that pregnant women who are exposed to high levels of air pollution during the third trimester of pregnancy may be twice as likely to give birth to children with autism.

The authors of the newly released study called for further inquiry into the facet of air pollution that covers "diverse traffic and geographical conditions in urban environments," so that the contribution of exposure at traffic intersections can be better understood.