I’ve written before about the developing science regarding the impacts of PM2.5 emissions. Short version – they’re bad for you. They’re even worse than we thought, and there’s increasing evidence that they cause a lot of harm at concentrations below the National Ambient Air Quality Standard of 12 ug/m3.
The most recent report comes from Canada, which is particularly useful in measuring the impact of low concentrations of PM2.5 precisely because PM2.5 concentrations are relatively low there. Tracking a large cohort, the authors developed a concentration-response relationship, then applied that relationship globally. They found that the World Health Organization undercounts annual PM2.5 mortality by 1.5 million. More than 400,000 of those deaths are in areas with PM2.5 concentrations below the NAAQS.
EPA is currently deciding what to do with a recommendation to lower the NAAQS to somewhere between 8 ug/m3 and 10 ug/m3. I’m confident that EPA will accept that recommendation, but whether the NAAQS lands at 8 ug/m3, 10 ug/m3, or somewhere in between is beyond my powers of prognostication. I am confident, however, that in the long run, the science is only going to drive the recommended number lower.
And so we come to the topic of electric vehicles and electrification more generally. Even aside from the climate benefits of moving to EVs, the immediate public health benefits – largely in areas of environmental justice concern – will be substantial. We have to make clear that moving to EVs is not just to make wealthy elites feel as though they are helping address climate change. Would it help to sell the EV revolution to focus on the public health benefits from electrifying vehicles (and the economy more broadly)?
As I have said before, I think the right way to get at this problem is by comprehensive tightening of emissions standards rather than argument over ambient standards. Even this new report misses the mark on sorting out confounding exposure factors ( like adsorbed PAH near oil, gas and petrochemical sources, interstate exposures, size differences among states, and non- inhalation causes of excess mortality). How tight should the emission controls be? Well, how about the old paradigm “Best Technology Economically Achievable “?