The Environmental Protection Agency may soon crack down on the deadliest form of air pollution: fine particulate matter.

Fine particulate matter, also called soot or PM2.5 to reflect its microscopic scale of under 2.5 microns, caused more than 4 million deaths globally in 2019.

In Nashville, the largest source is natural gas in homes and buildings, followed by cars and trucks.

“It’s anywhere you have those products of combustion,” said John Finke, the air pollution control director for Metro Nashville.

Nashville measures this air pollution at two sites. Between 2019 and 2021, the city recorded an average annual level of 9.1 micograms per cubic meter of air.

Nashville may be forced to lower its air pollution 

EPA is proposing to lower its annual limit from 12 micrograms to 9 or 10. If it picks 9, then Nashville will be subject to additional federal regulations for being in “non-attainment.”

“That’s a very tough pill to swallow for the city. Non-attainment is an economic killer,” Finke said.

The extra regulations for non-attainment involve tackling industrial sources of pollution. In 2020, Nashville’s largest stationary source of PM2.5 was Carlex Glass, an automotive glass manufacturer. There are also “area” sources like construction sites, waste facilities and farms.

Finke says fixing non-attainment would require a massive undertaking by the city.

Take cars and buildings: Ending this scattered fossil fuel burning requires electrification. The recently-passed Inflation Reduction Act does offer incentives for both residential and vehicle electrification, since this helps both reduce pollution and climate change.

Fossil fuel groups are fighting electrification, especially through state legislatures. The Tennessee General Assembly recently passed a law that preempts any local ban of natural gas in new buildings.

These groups are also fighting EPA’s proposed rule. The American Petroleum Institute, for example, came out against the rule, which would make companies spend more money controlling the pollution they create.

‘The air we breathe influences the risk’

EPA estimates that the proposed standard of 9 micrograms would cause about $400 million worth of annual compliance costs.

EPA’s analysis also estimates that up to 4,200 premature deaths would be avoided in the next decade — and the U.S. would see $43 billion in health benefits.

“These are very important steps to lower exposure across the board,” said Dr. Leonard Bacharier, a pulmonologist at Vanderbilt University Medical Center.

Fine particulate matter causes a host of health problems because it attacks the heart and lungs.

Asthma is a big concern, and it represents a classic example of a health disparity, according to Bacharier.

“Asthma is really influenced by the environment,” Bacharier said. “The air we breathe influences the risk of developing asthma in the first place, how active the asthma is going to be and the risk of having asthma flares.”

Location matters. Busy highways, oil refiners and factories — the highly polluting sites built next to Black or minority communities and away from white communities because of, in short, racism — are significant factors in asthma.

About 9% of children and 10% of adults in Tennessee have the chronic condition, which is a consistent inflammation in the lungs that has consequences ranging from exercise avoidance to lower school performance.

“Every child I know with asthma has had a family event, a vacation, a birthday … interrupted or ruined by an asthma episode,” Bacharier said.

Most health experts, including EPA’s own Clean Air Scientific Advisory Committee, want the agency to enact stronger standards than currently proposed for both the annual limit and the daily threshold.