Most people other than Andrew Wheeler and the Trump Administration Clean Air Science Advisory Committee know that exposure even to low levels of PM2.5 causes increased morbidity and mortality. And now comes evidence that exposure to PM2.5 may adversely impact cognitive capacity as well. If the evidence is correct, then the externalities created by activities that release PM2.5 are likely much more significant than we had realized, shifting the cost/benefit analysis even further towards more stringent regulation of particulate exposure.
The recent work is summarized in a fascinating new episode of Freakonomics Radio. The episode is not just about the impacts of PM2.5 on cognition. It also includes a discussion of what could be considered early environmental justice impacts of industrialization. Over the course of the 19th Century, as coal combustion increased dramatically, population shifts occurred, with the result being that, by the end of the 19th Century, poor people came to live in the more heavily polluted areas. Cause and effect aren’t clear, but the disproportionate impacts seem pretty well established and should be of concern whatever the cause.
As to cognition, let’s just say that the science is not fully developed. Still, I’ll give the perfect blog teaser to pique your interest. Freakonomics discusses a study that shows that baseball umpires make more mistakes when the game is played in an area with higher PM2.5 concentrations. I love this. Someone actually came up with the idea of studying umpires’ performance to measure the impact of PM2.5 on productivity.
Time will tell whether PM2.5 exposure really does affective cognitive ability. However, this much I do know – the epidemiological evidence has been pretty much running in one direction: the more we know about PM2.5, the worse it looks, and the more it seems that stringent regulation of PM2.5 is justified.