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Virus Prompts California to Study Air Pollution, Public Health

April 29, 2020, 10:01 AM

California regulators are seizing on a chance to study the public health effects of air pollution, as stay-at-home orders and drops in freight traffic related to the coronavirus pandemic have presented a unique research opportunity.

Gov. Gavin Newsom (D) issued statewide orders in March closing nonessential businesses, banning large gatherings, and ordering residents to stay home. Shipping and freight transportation traffic also fell due to the lockdown, bringing clear skies, empty roads, and more people working from home—aspects of California life previously thought to be nearly impossible.

The California Air Resources Board is taking notice, with an eye on environmental justice communities.

Long-term exposure to air pollution can cause asthma, respiratory issues, lost work days, and increased hospitalization. Disadvantaged communities often feel the brunt of the effects by living near industrial sites and transportation corridors, which advocates refer to as diesel death zones.

Researchers are comparing vehicle miles traveled, air pollution, traffic counts, and freight traffic to days before the spike in Covid-19, the disease caused by the coronavirus. They also plan to do a California-focused study similar to one conducted by Harvard University that looked at how air pollution affects susceptibility to the disease that is spreading across the globe.

“We have to recognize in this crisis there is an opportunity for learning,” Air Board Chairwoman Mary Nichols said during a public meeting April 23.

More attention needs to be paid to air pollution and health in terms of economic development and equity, said Phoebe Seaton, co-executive director and co-founder of the Leadership Council for Justice and Accountability.

“I am happy to see kind of more attention given there and would hope that that would expand to the state as a whole,” Seaton said.

The effort is California-specific, but other states could model work in the same way.

Influencing Factors

The Harvard study found that an increase of one microgram per cubic meter of fine particulate matter is associated with a 15% increase in the Covid-19 death rate.

California hopes to do the same evaluation but down to the census tract level, said Bonnie Holmes-Gen, chief of the Health and Exposure Assessment branch at the Air Board.

Evaluating each census tract will enable the state to take a more granular look because those boundaries cover populations of roughly 2,500 to 8,000 people. That means lower-income and wealthy areas could be examined separately.

The state study will also look at more pollutants and include hospitalizations, while the Harvard research focused on mortality alone.

Age, ethnicity, occupation, pre-existing conditions, and access to medical care may also be a part of the study, which is being finalized.

“A number of factors influence vulnerability to illness,” Holmes-Gen said April 27.

Focusing on census tracts means the state could hone in on minority and low income areas, particularly those by freight hubs or high traffic areas. But it’s too soon to tell how the information will inform future policy decisions.

“It’s a very unique experience that we’re going through,” Holmes-Gen said. “We want to look at what we can learn from this.”

Disparity Findings

A 2019 study by the Union of Concerned Citizens found that minorities in the state were exposed to more fine particle pollution—the PM 2.5 type cited in the Harvard study—than white populations.

Compared to white residents, exposure to the pollution from cars, buses, and trucks was 43% higher for African Americans, 39% higher for Latinos, and 21% higher for Asians, the study found.

In addition, low-income households live in areas where the fine particle pollution is 10% higher than the state average, while higher-income households live where that same type of pollution is 13% below the state average.

There still isn’t sufficient accounting for the health benefits of reducing pollution, said Bill Magavern, policy director at the Coalition for Clean Air.

“This is a time when public health is more important, particularly when our respiratory health is under attack from the Covid-19 infection,” Magavern said.

Water Tracking

The State Water Resources Control Board is also looking into ways to track when coronavirus first entered wastewater treatment plants. The facilities are set up to treat and remove viruses so there isn’t a transmission concern, Water Board Executive Director Eileen Sobeck said.

But if researchers can figure out when the virus arrived, it may help systems detect future viruses to act as an early warning.

The board isn’t recommending statewide monitoring now because it could pull resources, such as personal protective equipment or compounds used in testing, away from others who need it more, said Claire Waggoner, a chief in the division of water quality.

But in the future, wastewater monitoring could be more “cost effective than conducting health screenings for individuals in the population,” Waggoner said in an email.

Waggoner and a colleague are participating in an international research summit this week sponsored by The Water Research Foundation about Covid-19 indicators in sewersheds. The focus includes best practices to identify indicators, and estimate how virus concentrations translate to community prevalence.

“This is a time when we’re desperately in need of such an indicator,” Foundation CEO Peter Grevatt said during the summit.

To contact the reporter on this story: Emily C. Dooley at

To contact the editors responsible for this story: Gregory Henderson at; Rebecca Baker at