In-Car Exposure To Particulate Air Pollution Twice As High As Previously Thought

The levels of some forms of particulate air pollution (PM2.5 in particular) present inside of car cabins while driving are up to twice as high as previously estimated, according to a new study that was performed as part of the Atlanta Commuter Exposures (ACE) Study.

To put that in way that’s perhaps clearer, many earlier studies have relied upon traffic pollution sensors placed on the ground alongside the road for their data, whereas the new study utilized specially designed sampling devices placed into the passenger seats of cars during rush hour commutes in downtown Atlanta in the morning.

These in-car sensors detected levels of particulate air pollution up to two times higher than the levels detected by the roadside sensors. Interestingly, the sensors also revealed that the air pollution contained around twice the amount of oxidative-stress-causing chemicals as previously thought. The chemicals in question are known to be associated with the development of numerous cardiovascular, respiratory, and neurodegenerative diseases, as well as various cancers.

“We found that people are likely getting a double whammy of exposure in terms of health during rush-hour commutes. If these chemicals are as bad for people as many researchers believe, then commuters should seriously be rethinking their driving habits,” commented Michael Bergin, professor of civil and environmental engineering at Duke University.

The first author of the new paper, Heidi Vreeland, commented as well: “There are a lot of reasons an in-car air sample would find higher levels of certain kinds of air pollution. The chemical composition of exhaust changes very quickly, even in the space of just a few feet. And morning sun heats the roadways, which causes an updraft that brings more pollution higher into the air.”

That makes sense, and serves as a good example of why real-world testing and measuring is often so much more valuable than laboratory work — this being the case even when there isn’t a clear intention to either commit fraud or look the other way as it happens, as with diesel vehicle emissions testing in Europe.

Green Car Congress provides some details on the research process: “For the experiment, Roby Greenwald, a research assistant professor at Emory at the time, built a sampling device that draws in air at a similar rate to human lungs to provide detectable levels of pollution. The device was then secured to the passenger seats of more than 30 different cars as they completed more than 60 rush hour commutes.

“Some drivers took highway routes while others stuck to busy thoroughfares in downtown Atlanta. While other details like speed and having windows rolled down varied, all of the sampling found more risk in air exposure than previous studies conducted with roadside sampling devices.

“Reactive oxygen species found by this study can cause the body to produce chemicals to deal with the reactive oxygen. Particulate matter causes the same response. In combination, the exposure triggers an overreaction that can be destructive to healthy cells and DNA.”

In turn, the damage caused by regale oxidative stress is seemingly involved in the development of numerous diseases and developmental disorders, including: too many cancers to name, Alzheimer’s disease, atherosclerosis, Parkinson’s disease, Asperger’s syndrome, ADHD, autism, various types of infections, sickle cell disease, depression, and chronic fatigue syndrome, amongst others.

Study co-author Michael Bergin noted: “There’s still a lot of debate about what types of pollution are cause for the biggest concern and what makes them so dangerous. But the bottom line is that driving during rush hour is even worse than we thought.”

It should be realized here that this is the case whether one is driving an electric car or not — you’ll be exposed to the pollution released by the cars around you and roadway under you anyways. So, while driving an electric car may be better from the perspective of the pollution that one releases themselves, it of course doesn’t shield one from the air pollution all around. A real solution would be to drive less, if possible (I’m aware that this isn’t close to being possible for many in the US). Or, at the very least, try to limit your driving to outside of “rush hour” … if possible.

I suppose that some of those reading this will probably now make mention of high-end air filtering systems — the one available in the Tesla Model X, for instance — and, yes, if you’re rich enough to afford a car with such a system, then the issue doesn’t affect you as much. Everyone else, though…

The new findings are detailed in a paper published in the journal Atmospheric Environment.