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San Diego may fall short on new EPA soot pollution rules

Cesar E. Chavez Parkway in Barrio Logan on May 11, 2023.
Erik Anderson
The Cesar E. Chavez Parkway in Barrio Logan is seen on May 11, 2023.

The federal government is tightening the standards for acceptable amounts of soot pollution in the air, and San Diego County may fall short of compliance.

Only 15 counties in the United States currently fail to meet the existing soot pollution standard, also known as particulate matter 2.5 (PM2.5). The Environmental Protection Agency estimates that 119 counties, including San Diego, will fall short of the new lower standard.

News that the EPA is lowering the amount of acceptable particle pollution from 12 micrograms to 9 micrograms per cubic meter was met with cheers.


“The science is clear,” Michael Regan, the administrator of the EPA, said when he unveiled the changes in February. “Soot pollution is one of the most dangerous forms of air pollution, linked to a range of serious and potentially dangerous illnesses, including asthma and heart attacks.”

Soot comes from burning wood, dust, vehicle exhaust, factories and basically anything that consumes fossil fuel. The particles are the smallest airborne pollutants, which are easily inhaled.

It takes roughly 30 of the largest PM2.5 particles to equal the width of a human hair.

Lowering the amount of airborne soot also lowers how much money the nation spends on health care.

“An impressive estimated $46 billion, billion with a B, in avoided health care and hospitalization costs by the year 2032,” Regan said.


According to air quality regulators, the biggest source of air pollution in San Diego is not factories or cars. It is homes. Residential fuel consumption and cooking, both indoor and outdoor, are two of the three largest contributors, according to the San Diego County Air Pollution Control District.

That is why California’s clean air officials are looking for ways to phase out gas-burning appliances.

“Because of the significant contribution they make to outdoor air pollution in this case, particle pollution, everything from furnaces to water heaters and even stoves,” said Will Barrett, a spokesman for the American Lung Association.

“Not being in attainment is heartbreaking because we know what that means for our communities.”
Nicholas Paul, Environmental Health Coalition

Local regulators have time to consider how to move forward.

That means that air quality officials will spend a lot of time reviewing existing pollution rules, looking for ways to bring the amount of pollution down.

“They’ll have to evaluate if those are going to do enough or if they have to tweak some existing rules or move ahead with new rules altogether,” Barrett said.

San Diego County Air Pollution Control District officials concede that the region will likely be out of compliance when the new standard takes effect.

Right now, the district constantly measures PM 2.5 at nine sites scattered around the region.

The San Diego County Air Pollution Control District recorded a yearly average of 11 micrograms in 2022, up from 10 micrograms the year before.

If air quality officials cannot get the region in compliance by 2032, they could face severe penalties, including the loss of federal highway funding.

That outcome is rare, but officials are already looking for a road map to compliance

“That plan is going to look at the sources that we regulate in San Diego County, predominantly stationary sources, and identify where we can achieve additional emission reductions from those sources in order to meet that standard,” said Paula Forbis, San Diego’s air pollution control officer.

By stationary sources, Forbis is referring to things such as factories and power plants.

Regulators also want to reevaluate whether homes are still one of the biggest sources of PM2.5 pollution, or whether that impact has been overestimated.

But it may not happen quickly, because San Diego County has issues that local air quality regulators cannot fix.

“The state, California Air Resources Board, along with EPA, has jurisdiction over motor vehicles. EPA has sole jurisdiction over sources such as locomotives,” Forbis said.

Also, California’s Office of Environmental Health Hazard Assessment finds that the highest concentration of soot in the county’s air is near the international border.

Local regulators cannot do anything about dirty air that originates in Mexico.

The possibility that San Diego will not meet clean air rules for particulate pollution hits particularly hard in communities along the border and near the working waterfront.

“Not being in attainment is heartbreaking because we know what that means for our communities,” said Nicholas Paul, of the Environmental Health Coalition.

Air pollution has long been concentrated in so-called environmental justice communities, which carry a disproportionate share of a region’s pollution burden. Those communities are frequently less affluent and more racially diverse.

It was something the EPA pointed out when officials announced the tighter air pollution standard.

A University of San Diego study with the Environmental Health Coalition found that Barrio Logan residents have an 85% higher risk of developing cancer than the U.S. population on average.

“There is no safe level of PM pollution, right!?” Paul said. “All that contributes to the asthma, the elevated cancer risk that we are talking about.”

California’s environmental assessment tool, CalEnviroScreen, identifies San Diego’s portside and border communities as among the most polluted regions in the state.