The Biden administration announced Jan. 6 it will issue a proposed rule to tighten one of its national ambient air quality standards for particulate matter (PM), specifically for the smaller, fine particles of the PM2.5 category.
Particulate matter, often called soot, is a common emission from refineries and petrochemical plants, and it can be emitted wherever fossil fuels are burned, such as from diesel-fired generators at oil and gas drilling sites.
The Environmental Protection Agency (EPA) said its proposal is to lower the primary (health-based) annual PM2.5 standard to a level between 9 and 10 micrograms/cu m, down from the current level of 12 micrograms/cu m.
The text of the proposed rule was not immediately available. There will be a 60-day public comment period after it is published in the Federal Register.
EPA said it plans to finalize the rule by yearend.
Health benefits estimated
“These particles may be emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks, or fires,” the agency’s announcement said. Other particles “form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industrial facilities, and vehicles.”
Such emissions especially can contribute to lung disease if the particles lodge in the lungs.
EPA said it estimates that if finalized, a rule lowering the standard to 9 micrograms/cu m would prevent up to 4,200 premature deaths per year and 270,000 lost workdays per year, and would lead to as much as $43 billion in net health benefits in 2032.
EPA said it will take public comment on the full range—between 8 and 11 micrograms/c m—included in the Clean Air Scientific Advisory Committee’s latest report.
It has already gotten some comment from environmental activists. The Natural Resources Defense Council, the Environmental Defense Fund, and the Sierra Club all released statements Jan. 6 saying EPA should require a tighter 8 microgram standard, not something in the 9-10 range proposed.
Other regulatory options
The agency said it also is proposing to revise other aspects related to the particulate standards, such as monitoring requirements.
There are several particulate matter standards. The proposed revision is specifically for a health-based annual standard for PM2.5, but there also is a primary 24-hr PM2.5 standard set at 35 micrograms/cu m. EPA proposes to leave that 24-hr standard unchanged, although it added that it will take comment on revising it to as low as 25 micrograms.
The EPA last tightened the health-based 2.5 standard in 2013, after a 2012 review of the science. EPA’s new proposal is, like many Biden administration initiatives, a reversal of a Trump administration decision. The Trump EPA proposed in April 2020 to maintain the existing standard because the latest science was uncertain as to the benefits of lowering the standard.
That 2020 proposal—finalized in December of that year—was welcomed by a variety of industry groups, including the American Fuel & Petrochemical Manufacturers (AFPM), whose members include most US refiners and petrochemical makers.
“The United States has made incredible progress on reducing emissions, while continuing to deliver the essential fuel and petrochemical products that serve as the backbone of the global economy. Since 2000, PM2.5 concentrations have dropped 39 percent,” AFPM said in April 2020. “This proposal to maintain the standards will continue this progress.”
The public may be most familiar with the sight of soot billowing from a truck exhaust on the roads. EPA addressed that subject with a final rule issued Dec. 20 to toughen the emission standards for heavy-duty trucks starting with the 2027 model year.
