The road ahead of you is free-flowing finally! You get passed all that traffic and are finally moving at a good pace. As you come up to the intersection, the light turns yellow. The car ahead of you stops, and if your in New Jersey, you honk because it was clear both of you could have made it through. None-the-less, you are stopped at this red light and it is pretty annoying. But what if I told you it was also bad for your health to be stopped at this light?
A University of Surrey study found that drivers stopped at traffic lights are “exposed to harmful nanoparticles” while stopped at a traffic light. These nanoparticles are being released by the vehicles at the lights. According to the study, approximately 25% of the time drivers are exposed to these nanoparticles, they are at traffic lights. However, they are only at traffic lights 2% of the time they spend driving. That is a significant amount of exposure for an occurrence that only happens 1/50 of the time one spends driving.
So will keeping the windows shut or turning off the fan keep the amount of exposure to these harmful nanoparticles down? The study tested this theory with an experimental trial featuring a control group where the windows were wide open (See Table: Set 1). The trial also featured groups where the windows were shut, but with the fan slightly on with the heat (Set 2) and fully on (Set 3). Another group featured the windows shut with the heat on (Set 4).The last group featured the windows shut and the fans off (Set 5).
Table A explains the Particle Number Size Distribution (PND) which is the exposure to the nanoparticles in each setting. Set 1 is clearly the most exposure, whether it is morning or evening, with the windows down. Using both heat and fan in Set 2 also created more exposure than the other choices. Using the fan and heat individually in Set 3 and Set 4, respectively, created slightly less exposure than the previous settings. The least exposure during the settings was Set 5 with windows up with the fans and heat off.
This study, even though it is individual, does indicate the nanoparticles are least harmful at traffic lights if the windows are shut with the fans and heat off. The exposure was least in this case. There are not other studies to compare with this studies results or do a meta-analysis on, but the well-done nature of the experimental trial makes its findings somewhat trustworthy. Based on the results, it appears stopping at traffic lights is harmful and it is wise to keep the windows shut with the fans/heat off when stopped at a red light or avoid intersections as much as possible.