The White House Environmental Justice Advisory Council recently weighed in on EPA’s decision whether to lower the National Ambient Air Quality Standards for PM2.5 and ozone. 
Specifically, with respect to PM2.5, WHEJAC recommended that the annual primary standard be lowered to 8.0 ug/m3 and the annual daily standard be lowered to 25.0 ug/m3. Both recommendations are lower than what EPA has proposed.
With respect to the ozone NAAQS,… More
Last week, the EPA Clean Air Science Advisory Committee provided EPA its review of EPA’s Policy Assessment for the Reconsideration of the National Ambient Air Quality Standard for ozone. As expected, CASAC has disagreed with the recommendation of EPA technical staff to retain the current 70 ppb standard. Instead, CASAC recommends a significantly lower ozone NAAQS of 55-60 ppb. 
This seems to be coming down to a fight between EPA’s reliance on controlled human exposure (CHE) studies and CASAC’s position that EPA is giving too little weight to epidemiological studies,… More
Last week, Inside EPA (subscription required) reported that the Clean Air Science Advisory Committee has pretty much agreed that the National Ambient Air Quality Standards for ozone must be made more stringent. Apparently, the panel is looking at recommending that the primary standard be reduced from 70 ppb to a range of 55-60 ppb. CASAC is also recommending a reduction in the secondary standard.
I’ve blogged numerous times about the role that CASAC recommendations play in judicial review of EPA’s decisions concerning setting the NAAQS. … More
Last week, D.C. Circuit Court of Appeals rejected challenges to EPA’s “Revised Cross-State Air Pollution Update Rule”. The Court found that the Rule was “an appropriate exercise of EPA’s statutory authority”. 
I find the decision noteworthy for two reasons. First, the decision is a full-throated endorsement of judicial deference to agency decision-making. Of course, this isn’t a Chevron case;… More
On Friday, EPA announced that it was reconsidering its 2020 decision to leave the National Ambient Air Quality Standards for ozone unchanged. The reconsideration will be based on the existing record. The notice does not identify any specific perceived flaws in the 2020 decision. However, EPA stated that it:
will reconsider the decision to retain the ozone NAAQS in a manner that adheres to rigorous standards of scientific integrity.… More
Yesterday, EPA formalized its decision to leave the ozone NAAQS unchanged, at 70 ppb. I don’t think that this decision is in the same category of egregiousness as EPA’s recent decision not to reduce the PM2.5 NAAQS. After all, only one decision can be the single worst environmental policy of an entire administration.
I’m not that close to the science on the ozone NAAQS,… More