How to reduce exposure to pollutants while stuck in traffic

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New study says simple adjustments to a car's ventilation system during traffic jams can reduce exposure to pollutants by up to 76 percent.

We can now thank outdoor air pollution for seven million premature deaths a year, according to the World Health Organization (WHO), which ranks it among the top 10 health risks faced by our species. In London, for example, air pollution kills more than 10-times the number of people than traffic accidents do. In urban areas, says WHO, outdoor air pollution is as carcinogenic to humans in October 2013 as smoking was in February 1985. What a mess.

Looking at the problem, last year a group of researchers led by the University of Surrey's Dr. Prashant Kumar found that drivers stopped at traffic lights were exposed to up to 29 times more harmful particulate matter than those driving in moving traffic. In a new study, Prashant takes a look at reducing exposure to these pollutants.

What he and his team found is that when stuck in traffic, if we close the windows and turn off the fan – or turn the fan on recirculating – we have the lowest exposure to the pollutants.

"Where possible and with weather conditions allowing, it is one of the best ways to limit your exposure by keeping windows shut, fans turned off and to try and increase the distance between you and the car in front while in traffic jams or stationary at traffic lights,” say Prashant. “If the fan or heater needs to be on, the best setting would be to have the air re-circulating within the car without drawing in air from outdoors."

While this may not be rocket science, what is surprising is just how effective it is. With the windows closed and fan and heating switched off while under “delay conditions" (euphemism for "crazy-making traffic jam"), the researchers measured a 76 percent reduction of “in-cabin” exposure to PM1 (particulate matter of 1 micron or less in diameter and thought to be the most harmful). Having the windows closed and recirculating fan on was the best scenario for reducing other sizes of PM, but overall, the study recommends the windows-closed-fan-off combination for the best reduction of exposure.

Not great news for those of us who get antsy without fresh, or at least moving, air – but at least it's good to know how to protect our poor bodies from this assault of pollutants. And it all really makes one wonder: If we keep adding pollution-sputtering cars to congested cities – rather than opening them up more to cyclists and pedestrians – how long until urban denizens will all need scuba gear or spacesuits to simply survive the air?

The current research was published as part of the 2016 Emerging Investigators Issue in the Royal Society of Chemistry's Journal Environmental Science: Processes and Impacts.

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