EPA’s Office of Air Quality Planning and Standards has released a draft of its reassessment of the adequacy of the current national ambient air quality standard for particulate matter. Here’s the primary takeaway concerning PM_2.5:

The risk assessment estimates that the current primary PM_2.5 standards could allow a substantial number of PM_2.5-associated deaths in the U.S.

When taken together, we reach the preliminary conclusion that the available scientific evidence, air quality analyses, and the risk assessment, as summarized above, can reasonably be viewed as calling into question the adequacy of the public health protection afforded by the combination of the current annual and 24-hour primary PM_2.5 standards.

I just noted this Administration’s tendency to ignore scientific evidence of negative externalities. It will be interesting to see what EPA does when its own scientists are the source of the analysis. It’s pretty clear that environmental and public health NGOs will argue for a standard no higher than 8.0 micrograms/cubic meter. The analysis may give EPA sufficient wiggle room to propose a standard as high as 10 ug/m³. The real question will be whether EPA somehow tries to figure out a way to keep the current standard.

I’ll go out on a limb and make a few early predictions:

1. EPA will propose a standard of 10.0 ug/m³
2. If EPA proposes to keep the current standard, it will lose in court.
3. If EPA does propose a standard of 10.0 ug/m³, it will face challenges from both industry and environmental groups. The industry challenges will definitely lose. The environmental group challenges will be a close call.

You heard it here first.