Most Americans Are Breathing Cleaner Air—But Disparities Persist

U.S. air pollution has dropped substantially in recent decades, but not everyone has benefited equally from the decline and some demographics were breathing dirtier air in 2010 than in 1970, according to research set to be published Wednesday in Nature Communications.

Researchers at Columbia University's Mailman School of Public Health studied air pollution changes in the four decades following the enactment of the landmark Clean Air Act, with a focus on racial, ethnic, and socioeconomic disparities in emissions reductions at the county level.

"The analyses provide insight on the sociodemographic characteristics of counties that have experienced disproportionate decreases in air pollution emissions over the last 40 years," said Yanelli Nunez, an environmental health scientist at the Columbia Mailman School and the study's lead author.

Specifically, the researchers found that nationwide air pollution levels from all source sectors except ammonia emissions from agriculture and organic carbon particles from homes fell between 1970 and 2010.

However, according to a statement from the Columbia Mailman School, "an increase in a county's average Hispanic or Indian American population percentage resulted in a relative increase in sulfur dioxide, nitrogen oxides, and ammonia emissions from the industry, energy generation, and agriculture sectors, respectively."

Nunez asserted that "policies specifically targeting reductions in overburdened populations could support more just reductions in air pollution and reduce disparities in air pollution exposure."

"This is an important lesson gained from 53 years of Clean Air Act implementation," she added, "which is particularly relevant as we develop policies to transition to renewable energy sources, which will have a collateral impact on air quality and, as a result, on public health."

According to a 2023 report published by the Energy Policy Institute at the University of Chicago, global air pollution is reducing human life expectancy by an average of more than two years. Research has also shown that long-term exposure to the deadly effects of air pollution increases the risk of dying from heart disease or having a heart attack.