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Air Pollution Is Hardening Your Arteries

Just breathing is killing you.
Photo: Warner Hocker/Flickr

That air pollution kills over 7 million people each year, more than AIDS and malaria combined, and that car exhaust is one of the fastest growing causes of death, are both pretty abstract, right? How about this latest bit of info on the harm caused by air pollution to make things more personal: New research in PLoS Medicine shows that air pollution can speed up the hardening of your arteries, leading to more heart attacks and strokes.

The study, conducted by professors from the University of Michigan and the University of Washington, found that higher concentrations of fine particulate air pollution (PM2.5) are linked with faster thickening of the inner layers of the carotid artery. Reducing this pollution slowed the thickening of these layers.

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Looking at over 5000 people between the ages of 45 and 84 from six US cities, and adjusting for other factors that could contribute to hardening of the arteries, they found that "people living in a more polluted part of town may have a 2% higher risk of stroke as compared to people in a less polluted part of the same metropolitan area."

To put this in perspective: This study looked at people living in Baltimore, Chicago, Los Angeles, New York, St Paul, and Winston Salem. The highest concentrations per cubic meter of PM2.5 pollution were in LA, at 23. The lowest were in St Paul, at 11.9, with the rest of the cities in the mid-15s range. Anything over 25 is generally considered to be unhealthy air quality. So all these cities, including smoggy LA, are under that threshold. Yetl the risk of heart attack and stroke increased—not a huge amount, but a significant one.

Compare this to what we've seen in China so far this year. Back in January air pollution in Beijing was so bad it went off the top of the US chart, which stops at 500 parts per cubic meter. In the first two weeks of January concentrations of PM2.5 pollution were regularly above 700, topping out at 886—37 times worse than the air pollution in Los Angeles, as measured in this study, and 54 times worse than the average air pollution for all the cities considered.

In the light of what this study shows for US cities, you have to wonder just how much worse this is for the cities of China—where 16 of the 20 worst-polluted cities in the world are. It also makes me wonder if 8,500 premature deaths caused by air pollution in China, as determined by a Peking University study, might not be underestimating things a bit.

Not to mention the effect of air pollution in places where air pollution is even worse than China: Like Ahvaz, Iran and Kabwe, Zambia.

Oh, and in case you forgot, or never knew in the first place: Air pollution has also been linked to brain damage, memory loss, and Alzheimer's disease.