US EPA won’t strengthen particulate matter limit

In a move backed by the US chemical industry, the Environmental Protection Agency (EPA) is proposing to keep the existing clean air standard for fine particulate matter rather than to strengthen it.

Breathing in fine particulate matter is linked to heart attacks, decreased lung function, asthma attacks, and premature death in people with heart or lung problems.

“With air quality improving, EPA’s decision will enable further environmental progress under the current standards and emissions controls,” the American Chemistry Council, the largest lobbying group of chemical manufacturers, says in a statement.

In practice, retaining the current standard of 12 µg/m³ of air for particulates that are 2.5 µm or less in diameter means most chemical plants won’t have to adopt more stringent pollution controls for particulate precursors such as nitrogen oxides and sulfur dioxides.

Health groups and environmental activists decry the EPA’s April 14 proposal to keep the standard, set in 2012. They say scientific evidence shows the fine particulate matter limit needs tightening.

“It’s especially egregious that EPA is making this announcement in the thick of the COVID-19 pandemic,” says Gretchen Goldman of the Union of Concerned Scientists in a statement. She points to early results from a study by Harvard researchers that found that a small increase in long-term exposure to fine particulate matter leads to a large increase in the death rate from COVID-19, the disease caused by the SARS-CoV-2 virus.

EPA Administrator Andrew Wheeler calls the Harvard study “interesting” but says it’s premature to draw conclusions from the results, which haven’t been peer reviewed yet. That work will not be considered as the agency finalizes the particulates proposal, which Wheeler hopes will happen by December.

“The current standard remains protective of public health,” he says.

The agency’s staff last fall recommended the EPA lower the fine particulate standard to between 9 and 11 µg/m³. In a split vote, the EPA’s Clean Air Scientific Advisory Committee, a panel of outside experts, recommended keeping the current standard.