Brian Zhang, Contributing Photographer

Underlying the strict air pollution regulations in California is a failure to provide proportionate protection to people from minority and low-income neighborhoods, a team of Yale and University of California, San Diego researchers found.

When Luke Sanford, assistant professor of environmental policy and governance, and his colleagues at the Yale School of the Environment were walking down the streets of San Diego at the height of the pandemic, they saw almost no cars. A feeling of austerity and quiet permeated the cityscape that was once vibrant with beach life and traffic. Multiple pieces of published literature already detail how the pandemic as a whole helped curb air pollution, but the group was specifically interested in how changes in air quality varied across different neighborhoods in California. After checking the air quality sensors in a number of cities, they found significant disparities among communities in exactly how much air quality improved. The team’s work was published in the journal Nature Sustainability.

“In places where primarily white people live in — people with higher income — there wasn’t actually that much of a change in air quality,” Sanford said. “And then in places where Hispanic, Latinx and Asian people lived in — people with lower incomes, there were much larger reductions in air pollution.”

According to Sanford, there are two ways to approach this data. While one can see the improvements in air quality in communities of color and lower socioeconomic status as a sign of progress, the team of researchers preferred to go backwards in time — to use the pandemic data to envision the historical inequalities that existed in pre-pandemic times, as well as explore what charted such inequalities in the first place. 

According to Richard Bluhm, an assistant professor of macroeconomics at Leibniz University Hannover, before the COVID-19 pandemic broke out, the task to determine the most important factor leading to disparities in air quality across communities was challenging, given the U.S.’ longstanding history of environmental injustice and confounding variables in power plant generation, climate and road density. 

However, with the shutdown of the transportation sector, the pandemic presented the perfect opportunity to study a California that has strayed away from its pre-pandemic in-person economy. After finding that power plant generation levels did not change much during the pandemic, Sanford’s team pointed to transportation as the main culprit for these disparities across communities: a 97 percent reduction in overall transportation emissions during COVID-19 led to major improvements in air quality for communities that had poor air quality before the pandemic. 

By tracking anonymous GPS ping data from mobile phones across communities, the researchers learned that during the pandemic, people whose home locations were registered as part of primarily minority and low-income neighborhoods commuted for longer than their white counterparts. 

According to Sanford and Bluhm, one possible explanation for this is that people of color made up an overwhelming proportion of the essential workforce. Initially, this finding did not align with the fact that air quality improved much more in communities of color than in white communities — should more frequent driving not correlate with greater emissions levels and thus poorer air quality?

“Is it you driving around or is it everybody else driving through your neighborhood that’s causing [these] pollution disparities?” said Bluhm, suggesting that more people were driving through communities of color during pre-pandemic times. 

This aligns with the fact that historically, freeways in California have been built through communities of color, said Pascal Polonik, a doctoral candidate at the Scripps Institute of Oceanography at the University of California, San Diego.

Bluhm added that there were further disparities within communities of color. For Asian and Hispanic-dominated neighborhoods, the once-steep pollution curves now resembled horizontal lines, supporting that air quality was improving drastically. For Black communities, however, there was very minimal change to the curves — an issue that Bluhm said requires further investigation and more data, given the underrepresentation of Black populations in California.

Moving forward, the group hopes that their work will bring to light which factors state officials choose to consider and prioritize when creating and implementing environment-related policies. Sanford noted that there is currently no equality standard for air pollution in California. Such a standard would be a critical measure to account for the disparities in air pollution and extent of environmental justice across communities. 

“This is systemic,” Polonik said. “There is probably no single way to address the issue … but policies that [engage] transit and non-car usage would … be beneficial.” 

Based on a 2018 analysis of 112 Californian cities, the state averaged a fine particulate matter concentration of 12.1 μg/m3, which exceeds the World Health Organization recommendation at an annual exposure of 10 μg/m3

Brian Zhang covers COVID-19 and Yale New Haven Health, as well as housing and homelessness. Originally from Brooklyn, New York, he is a student in Davenport majoring in English and creative writing.