Friday, March 27, 2015
Don't breathe the air
If you're among my 4 1/2 readers, you've heard about air pollution before. Exposure to indoor air pollution is the fourth leading risk factor for disease worldwide. That's mostly in poor countries where people burn wood or dung indoors for heat and cooking. But outdoor air pollution is the ninth leading risk factor worldwide, and that's not just because of China.
Here in the U.S., the highest exposures occur to people who live near major highways.
There is a very large body of evidence showing that in the United States, non-white and low SES people are more likely to live in proximity to local sources of pollution, including high traffic roadways. We already knew they are at high risk for cardiovascular disease and heart attacks. But now the new BMJ has two papers, one a meta-analysis confirming a high risk of stroke associated with exposure to particulate pollution, the other an observational cohort study finding that exposure to air pollution is associated with anxiety.
You may find the latter observation odd, but it's well controlled. Exposure to particulate pollution is associated with systemic inflammation, and it may be that there is a link to mental health. There are even indications that short-term variation in air pollution is associated with suicide.
Of course, it might be that there are factors such as traffic noise or lack of open space. Nevertheless, whatever the mechanism, this once again is probably the most salient problem of environmental justice in the U.S. When you push a ton of metal at 70 miles an hour down the highway by burning the residue of ancient plants, you are poisoning the unfortunate people who live and work along the route. Maybe we should do something about it.