I’ve written a lot about how the developing science around particulate exposure supports making the PM2.5 NAAQS more stringent. So it won’t come as a surprise that a new study published in the Proceedings of the National Academy of Sciences indicates that the benefits of on-road emissions reductions from 2008 to 2017 could be measured in the hundreds of billions of dollars and almost 10,000 fewer deaths. The authors go on to note that more stringent regulation would provide additional benefits in economic savings and reduced mortality.
It’s pretty clear to me that the study supports lowering the PM2.5 NAAQS. However, I think it does more – it supports getting rid of the NAAQS system completely. The Clean Air Act requires that NAAQS be set to protect the public health “with an adequate margin of safety”. Unfortunately, the PNAS study suggests – and this is not unique to particulate pollution – that the level that would truly provide “an adequate margin of safety” is probably very low, i.e., much lower that any levels currently under consideration by EPA.
The problem with the NAAQS approach is that, once the NAAQS is set, regulators and the regulated community only have an incentive to control emissions to reach or maintain the NAAQS. If we acknowledge that there are adverse impacts resulting from ambient concentrations below the NAAQS, we should want to provide incentives to the regulated community on a continuous basis. Imposing standards that set a NAAQS and then saying “Thou shalt not violate the NAAQS” fail to provide any incentive for continuous improvement.
I don’t pretend to be the first person to notice this flaw in the system. Among the many smart people who have addressed this issue is my friend Dan Esty, whose article “Red Lights To Green Lights: From 20th Century Environmental Regulation To 21st Century Sustainability” focuses in large part on making changes to our regulatory system so as to provide continuous incentives for reducing pollution.
Spoiler alert: There’s a tried and true means for doing so. It’s called the market.
It’s time to lower the PM2.5 NAAQS. It’s also time to replace the NAAQS approach itself with something better.