Category Archives: PM2.5

EPA has finally proposed revisions to the national ambient air quality standard for PM2.5.  The Administrator is proposing to lower the standard from 12.0 ug/m3 to a range of 9.0 to 10.0 ug/m3. 

Readers of this space will recall that the Clean Air Science Advisory Committee recommended that EPA lower the PM2.5 NAAQS to between 8.0 and 10.0 ug/m3.  Environmentalists aren’t going to be happy with any standard above 8.0 ug/m3 and it’s likely that conservatives aren’t going to be happy with any decrease from the current standard.… More

The International Energy Agency has released its 2022 Coal analysis and forecast.  It is sobering. By the time 2022 is over, world-wide coal consumption will have exceeded 8 billons tonnes for the first time.  In other words, 2022 was a record year for coal.  It is true that demand was largely flat compared to 2021 and there were some extraordinary reasons – such as a war in Ukraine – for even the moderate increase.… More

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. … More

Two developments this week got me thinking about how our government deals – or fails to deal – with risk.  First, EPA proposed to ban the manufacture (including import) of chrysotile asbestos.  EPA’s authority for doing so is the Toxic Substances Control Act which provides that:  

if EPA determines through a TSCA section 6(b) risk evaluation that a chemical substance presents an unreasonable risk of injury to health or the environment,… More

Last week, the Clean Air Scientific Advisory Committee formally transmitted its recommendations to EPA Administrator Regan regarding the PM2.5 NAAQS.  Consistent with trade press reporting over the past few months, the majority of CASAC members recommended that the PM2.5 NAAQS be set between 8-10 ug/m3.  A minority recommended the range be set between 10-11 ug/m3.  I’d be surprised if the revised NAAQS is set above 10 ug/3. 

For me,… More

An article in the Proceedings of the National Academy of Sciences (login required) has documented the devastating impact caused by the use of leaded gasoline.  The study estimates that more than half of Americans alive in 2015 had been subject to unsafe blood lead levels as children.  The study further estimates that the impact of these elevated blood levels was a net loss of 824,097,690 IQ points as of 2015. … More

EPA has proposed to revoke the Trump administration finding in 2020 that it is not appropriate and necessary to regulate emissions of air toxics from coal- and oil-fired electric generating units.  Instead, EPA proposes to reaffirm its 2012 and 2016 determinations supporting such regulation. 

This is not surprising and should not be controversial.  It may seem odd that I’m citing to the Edison Electric Institute twice in one week in support of EPA regulatory authority,… More

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. … More

I’m not sure it’s even really news at this point, but earlier this week Ameren Missouri announced that it would close its Rush Island Energy Center generating plant early, rather than spend the money to install flue gas desulfurization technology in response to an injunction issued after the District Court found that the Rush Island facility had violated the Clean Air Act.  As Ameren noted in its filing with the Court: 

Retiring Rush Island early will have a much more beneficial environmental impact,… More

The momentum continues to build for a more stringent National Ambient Air Quality Standard for PM2.5.  In June, EPA announced it would revisit the Trump Administration’s decision to keep the PM2.5 NAAQS at 12 ug/m3.  In early October, EPA staff released a supplement to its assessment of the PM2.5 NAAQS.  That supplement also supported a more stringent standard. 

Now, the Clean Air Science Advisory Committee is about to weigh in. … More

Earlier this week, Greenwire (subscription required) had an interesting story about the role that EPA’s estimate of the cost to comply with the Mercury and Air Toxics Standards rule played in the politics and judicial review of the rule.  It turned out that compliance costs were much less than originally estimated by EPA – let alone by industry.  Unfortunately, the $9.6 billion price tag originally put on the MATS rule lived on,… More

Late last week, EPA released an external review draft of the “Supplement to the 2019 Integrated Science Assessment for Particulate Matter.”  For those of you who don’t recall, the original Integrated Science Assessment was the report by EPA scientists that very clearly called for a decrease in the National Ambient Air Quality Standard for PM2.5.  It was criticized by the Chair of the Clean Air Act Science Advisory Committee and ignored by Administrator Wheeler,… More

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,… More

EPA announced yesterday that it will “reconsider” the Trump EPA’s decision not to change the PM2.5 National Ambient Air Quality Standard.  I’ve blogged numerous times about the growing body of evidence that exposure to concentrations of PM2.5 below the current NAAQS causes significant additional mortality and morbidity.  The evidence is clear.

I certainly agree that climate change is an existential threat and that’s where our emphasis needs to be. … More

I’ve frequently discussed in recent years the mounting evidence for the need to lower the National Ambient Air Quality Standard for PM2.5.  There is also substantial evidence that PM exposure is an environmental justice issue.  In this context, electrification of our transportation system is seen as having a substantial co-benefit in the reduction of vehicle-related PM emissions, particularly in EJ communities. 

Two recent stories both confirmed the validity of these issues and made manifest the complexity of the problems we are trying to solve. … More

The evidence of the harm resulting from PM2.5 exposures keeps rolling in.  Earlier this month, Environmental Research published an article titled “Global mortality from outdoor fine particle pollution generated by fossil fuel combustion: Results from GEOS-Chem” (abstract available; full article requires purchase), which concluded that global annual mortality from PM2.5 exposure is roughly twice as high as previously estimated. 

Somehow,… More

Last month, I posted that EPA’s decision to retain the current PM2.5 NAAQS of 12 ug/m3 was the single worst decision by Trump’s EPA.  Since then, I have not received any comments suggesting that my ranking was incorrect.  In case anyone was still in doubt, Environmental Research recently released an on-line Pre-proof of A National Difference in Differences Analysis of the Effect of PM2.5 on Annual Death Rates. … More

Yesterday, EPA finalized its decision to retain the existing PM2.5 NAAQS of 12 ug/m3, rejecting substantial scientific evidence that PM2.5 causes significant harm at concentrations below 12 ug/m3.  In fact, as noted in one of my prior posts on this subject, an article in the New England Journal of Medicine estimated that exposure to PM2.5 at concentrations below 12 ug/m3 causes more than 10,000 deaths annually. … More

In April, I noted that researchers at the T.H. Chan Harvard School of Public Health had identified a relationship between PM-2.5 exposure and mortality from COVID-19.  That study received some criticism, and it certainly did not move the Clean Air Science Advisory Committee to alter its recommendation to keep the PM2.5 NAAQS unchanged at 12 ug/m3.

Earlier this month, the same researchers updated the study,… More