Rush hour pollution may be twice as harmful as thought

A study of in-car exposure to pollutants that cause oxidative stress during rush hour commutes has revealed worrying results. The levels of some forms of harmful pollutants inside cars was found to be double what was previously believed.

The first measurements of exposure to pollutants inside cars has found the levels to be twice as high as previously thought.

Most traffic pollution sensors are placed on the ground by the road and take continuous samples for a 24-hour period. However, such measurements do not take into account variabilities caused by road congestion and environmental conditions.

Now, researchers in America have detected what drivers are actually exposed to during rush hour by strapping sampling devices, which draw in air at a similar rate to human lungs, into the passenger seats of cars in Atlanta.

The scientists from Duke University, Emory University and the Georgia Institute found that these sensors detected twice as much particulate matter as the roadside sensors.

Furthermore, the pollution contained twice the amount of chemicals that cause oxidative stress, which is thought to be involved in diseases including respiratory and heart disease and cancer.

“We found that people are likely getting a double whammy of exposure in terms of health during rush-hour commutes,” commented Michael Bergin of Duke University in a statement announcing the findings.

He warned: “If these chemicals are as bad for people as many researchers believe, then commuters should seriously be rethinking their driving habits.”

The researchers secured the device to the passenger seats of more than 30 different cars as they completed over 60 rush hour commutes. While factors such as speed and windows rolled down varied, all the sampling found more risk in air exposure than previous studies.

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

Research assistant Roby Greenwald concluded that the findings point to “an urban planning failure”.

He explained: “In the case of Atlanta, the poor air quality on the highways is due to the fact that 6 million people live in the metro area, and most of them have little choice but to get into an automobile to go to work or school or the store or wherever. Auto-centric transportation plans do not scale well to cities of this size.”

Photo credit: Prayitno/ CC BY 2.0

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