New method for mapping air pollution reveals disproportionate burden in disadvantaged communities
- 4 min. read ▪ Published
In recent years, environmental justice researchers have uncovered wide disparities in exposure to toxic pollutants between people living in low-income neighborhoods and those living in wealthier communities.
Much of the research has focused on air pollution emitted from factories, along with diesel truck and automobile exhaust from highways—which are generally situated far from high-income neighborhoods. Higher levels of air pollutants can cause adverse health outcomes.
But these previous studies have relied on limited data. They’ve generally used regulatory pollution monitoring reports that are collected as little as once a year—often from monitoring stations that are miles away from people’s homes—which don’t give an accurate, granular picture.
Jason G. Su, an environmental health sciences researcher at UC Berkeley School of Public Health, is changing that. Su led a study published in Science Advances that drew on a massive amount of data to create a nearly block-by-block picture of three air pollutants around the state of California.
“Our research revealed significant air pollution exposure disparities among vulnerable populations,” Su said. “However, what was pleasantly surprising was the observed decline in overall disparities related to traffic marker NO2 (nitrogen dioxide) and fine particulate matter exposure. This suggests that the gap in exposure is narrowing, which is an encouraging trend for public health.”
Su’s researchers used terabytes of data from 850 monitoring stations, weather and traffic reports; and other data from 2012 to 2019 to create daily air pollution maps for Fresno, Los Angeles, Sacramento, and the San Francisco Bay Area. They then matched the reports on three pollutants: NO2, particulate matter (PM2.5), and ozone, against census tract data showing race, ethnicity, and income.
“We found that communities with a higher proportion of minority populations were exposed to elevated concentrations of NO2 and PM2.5, compared to predominantly white communities,” the authors wrote.
“Our study revealed that disadvantaged communities are consistently exposed to higher air pollution concentrations than advantaged communities. Disadvantaged communities are often located near industrial facilities and manufacturing plants, major roadways, and other sources of pollution, leading to higher concentrations in nearby areas.”
The authors wrote that from 2012 to 2019, while the disadvantaged communities, described by lower-income census tracts, had higher levels of nitrogen dioxide and particulate matter than their more wealthy counterparts, their overall levels had declined, due to pollution reduction measures. They also wrote that ozone had increased in the wealthier communities, compared to the lower-income neighborhoods.
“Other people have done this, but not as elegantly as we have shown neighborhood levels of air pollution,” said Dr. John Balmes, emeritus professor of environmental health sciences at UC Berkeley School of Public Health and emeritus professor at UCSF, who co-authored the report.
By combining these different data sources through machine learning, Balmes said, Su was able to harness a massive amount of data from multiple sources, to create an air pollution map that shows distinctions neighborhood by neighborhood.
Balmes said that the research team will follow this study with an epidemiological study, examining the effect of air pollution on children’s school performance.
“The lower-income areas saw the biggest decline because they had the most pollution to begin with,” Balmes said. “Freeways, ports, railyards. They don’t put rail yards in Piedmont [a wealthy enclave that is surrounded by the city of Oakland].”
Su said his research team has expanded its fine-resolution data from eight years to over 30 years across California. This comprehensive dataset is now being utilized in several critical studies, including the impacts of air pollution on emergency department visits, hospitalizations, and mortality; preterm birth and low birth weight outcomes; life expectancy across multiple generations and cognitive decline.
“These studies will provide deeper insights into the health effects of air pollution, especially the impacts on vulnerable populations,” Su said.