On February 7, the EPA announced its revision of one of the National Ambient Air Quality Standards (NAAQS). It tightened the regulation of annual Fine Particulate Matter – particles measuring 2.5 microns or less, known as PM2.5 and sometimes referred to as soot. When a federal agency takes small steps to do something that helps protect communities and the planet, it’s worth taking a moment to appreciate it.
But there is a caveat (isn’t there always a caveat with good environmental news?). Since the revision of the standard was publicly announced, the AP reports that 25 states and a variety of industry groups have filed lawsuits challenging the EPA’s rule on PM2.5. So, let’s start with the good news, then move on to the bad.
The Clean Air Act of 1970 authorized the EPA to establish the NAAQS “to protect public health and public welfare and to regulate emissions of hazardous air pollutants.” The Agency, therefore, determines what it deems to be acceptable concentrations of five prevalent air pollutants – PM2.5, PM10, Ozone, Carbon Dioxide, NOx, and SOx. The EPA is also required to revisit standards periodically. In the case of PM2.5, it reviewed it in 2021in response to new scientific evidence and technical information. The review is what prompted the tightening of the regulation of ambient concentrations from 12 ug/m3 (shorthand for micrograms per meter cubed) to 9 ug/m3.
Could it be lower, safer, better? Yes, of course. Studies have shown public health risk exists at 5 ug/m3, which is the World Health Organization’s standard. But 9 ug/m3 is more protective than 12 ug/m3. Dr. Doris Browne, 118th President of the National Medical Association said, “Administrator Regan and President Biden deserve thanks for taking this vital step to curb soot pollution – a dangerous and even deadly pollutant that has taken an oversized toll on underrepresented and overburdened communities less equipped to deal with its severe health impacts.” She continued, “This new standard of 9 micrograms per cubic meter will save lives based on scientific evidence. That is the bottom line. And as a physician, an advocate for clean air, and the past president of the National Medical Association representing physicians, our ultimate goal is health equity.”
What is PM2.5 and what are the risks it poses?
PM2.5 is composed of droplets and particles measuring less than 1/30th the diameter of a human hair. It is most frequently associated with pollution from combustion activities – so any time fuel is burned in industrial processes, energy production, transportation, and in residential settings. Large industrial facilities are, of course, of greatest concern.
PM2.5 has long been known to be associated with acute and chronic health conditions, including cardiovascular and respiratory diseases. In January 2024, EPA released its Final Regulatory Impact Analysis (RIA) for the lowering of the PM2.5 standard. Among other public health benefits, the change is expected to avoid up to 4,500 premature mortalities per year for adults; over 2,600 hospital visits; 800,000 asthma events, and 290,000 lost workdays.
Getting to compliance
Most counties are already in compliance with 9 ug/m3. That is, their average annual PM2.5 concentration is at or below 9 ug/m3. Fifty-nine counties, however, will need to work with industry actors to lower emissions of PM2.5. Across these counties there needs to be a total reduction of almost 33,000 tons/year. Regionally, 21% of the reduction needs to be in the Northeast, 10% in the Southeast, 10% in the West (minus California), and 59% in California alone.
EPA has a tool for estimating emissions reductions and engineering costs associated with end-of-pipe control technologies and area source controls. It’s called the Control Strategy Tool (CoST). Reductions will primarily be achieved by two mechanisms: End-of-Pipe Controls (controlling the intentional discharge of emissions) and Area Source Controls (reducing emissions by changing processes or materials used). The EPA acknowledges that controls of these types won’t bring the total ambient concentration all the way but will go much of the way. Additionally, annualized control costs by 2032 are to be nearly $600 million. The AP reports, “EPA Administrator Michael Regan said the new soot rule, finalized last month, would create $46 billion in net health benefits by 2032…”
As stated at the outset – and not unexpectedly – this has not been uniformly greeted positively. On March 6 Reuters reported that many Republican attorneys general and industry groups filed three lawsuits challenging EPA’s action on PM2.5. Russell Coleman, Attorney General of Kentucky, filed a lawsuit against the change on behalf of 24 states. He said the revised standard would raise costs across sectors and would impact families. This rule will drive jobs and investment out of Kentucky and overseas, leaving employers and hardworking families to pay the price.” That same article reports, “Opponents have claimed that the rules could block permitting for new manufacturing facilities and stop new infrastructure construction.” These claims deserve their own blog post, so stay tuned for that.
The regulatory action by EPA and the challenges that have followed are occurring at a time when federal agencies’ authority is being challenged across a range of topics by some on the right. Who is in the White House and Congress come 2025 will determine whether environmental and climate regulations can gain more ground or can be constrained through legislation or court cases.