Drivers are exposed to very high levels of air pollution when they stop at red lights, a new study shows.
The British researchers tracked drivers' exposure to small bits of air pollution, called nanoparticles, as they drove their cars during a normal workday. Cars are known to emit nanoparticles, they added. These harmful pollutants have been linked to increased risk of lung and heart diseases.
At red lights, peak nanoparticle exposure was 29 times higher than when the cars were in free-flowing traffic, the study findings showed. Spending just 2 percent of a journey passing through intersections with traffic lights contributed to about 25 percent of drivers' total exposure to the harmful particles, the researchers found.
Reasons why drivers are exposed to higher levels of nanoparticles while at red lights include that the vehicles are closer together, and because drivers rev the engine to accelerate quickly when the light turns green, the University of Surrey researchers said.
The findings were published online Feb. 12 in the journal Atmospheric Environment.
"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," study author Prashant Kumar said in a university news release.
"It's not always possible to change your route to avoid these intersections, but drivers should be aware of the increased risks at busy lights. The best ways to limit your exposure is to keep vehicle windows shut, fans off and try to increase the distance between you and the car in front where possible," he suggested.
"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 [or overpasses]," Kumar added.
The World Health Organization has linked air pollution to 7 million premature deaths worldwide every year, Kumar noted in the news release.