Researchers at the University of Surrey monitoring a driver’s exposure to air pollutants find that stopping at red lights exposes the driver to high levels of pollution.

Road vehicles are known to emit polluting nanoparticles that contribute to respiratory and heart diseases, and where drivers spend 2% of their trip passing through traffic intersections managed by lights, this contributes to about 25% of total exposure to these harmful particles. For the study, researchers monitored drivers’ exposure to air pollutants during their trip.

The study revealed signalized traffic intersections were found to be high pollution hot spots due to frequent changes in driving conditions. A Science Daily news report notes that with drivers decelerating and stopping at lights, then revving up to move quickly when lights go green, peak particle concentration was found to be 29 times higher than that during free flowing traffic conditions. In addition, cars tend to be close together at traffic lights, increasing the likelihood of exposure to vehicle emissions.

Lead author of the study Prashant Kumar states, “Air pollution was recently placed in the top ten health risks faced by human beings globally, with the World Health Organization linking air pollution to seven million premature deaths every year. Our time spent travelling in cars has remain 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.”

Kumar adds that drivers should be aware of the increased risk at busy lights, so the best ways to limit exposure is to keep fans off, vehicle windows shut, and try to increase the distance between a driver’s car in front when possible. Kumar says, “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.”

Source: Science Daily