Poor air quality is the largest environmental health risk in the United States. Fine particulate matter pollution is responsible for more than 100,000 deaths each year from heart attacks, strokes, lung cancer and other diseases.
But not everyone is equally exposed to poor air quality, nor are all people equally responsible for generating it.
Black and Hispanic Americans bear a disproportionate burden from air pollution generated mainly by non-Hispanic white Americans, according to new research from a team led by the University of Washington and the University of Minnesota. The finding, which quantifies for the first time the racial gap between who generates air pollution and who breathes it, was published March 11 in the Proceedings of the National Academy of Sciences.
"Similar to previous studies, we show that racial-ethnic minorities are exposed to more pollution on average than non-Hispanic whites,” said first author Christopher Tessum , a research scientist in the UW’s civil and environmental engineering department and a recent University of Minnesota graduate. "What is new is that we find that those differences do not occur because minorities on average cause more pollution than whites - in fact, the opposite is true.”
The team compared what people spend their money on - like buying groceries or gas or getting clothes dry-cleaned - to the pollution these activities generate. Then the researchers overlaid these results on a map of where people live to see if there was the difference between the pollution that specific racial-ethnic groups generate and what they experience.
"Someone had to make the pen you bought at the store,” said co-author Julian Marshall , a UW professor of civil and environmental engineering. "We wanted to look at where the pollution associated with making that pen is located. Is it close to where people live? And who lives there?”
The team found that on average, non-Hispanic white Americans spend more money on pollution-intensive goods and services, which means they generate more pollution than other groups. But white Americans also experience a "pollution advantage” in that they are exposed to approximately 17 percent less pollution than they generate.
At the same time, black and Hispanic populations bear a "pollution burden.” On average, black Americans experience about 56 percent more pollution than they generate. For Hispanics, it is slightly higher: 63 percent.
These disparities may be influenced by longstanding societal trends, such as income inequality. Also, racial patterns in where people live often reflect segregation or other conditions from decades earlier. Black and Hispanic Americans are more likely to live in locations with higher concentrations of pollution compared to white Americans, which means they have increased average daily exposure to it.
In general, the U.S. has made strides to reduce air pollution across the country: Average exposure to particulate pollution declined approximately 50 percent between 2003 and 2015. But pollution inequity remained high over that same period.
"Our work is at the intersection of many important and timely topics such as race, inequality, affluence, environmental justice and environmental regulation," said corresponding author Jason Hill , an associate professor of bioproducts and biosystems engineering at the University of Minnesota.
The team hopes this pollution-inequity metric can provide a simple and intuitive way for policymakers and the public to see the disparity between the pollution that population groups generate and the pollution to which they are exposed.
"The approach we establish in this study could be extended to other pollutants, locations and groupings of people," Marshall said. "When it comes to determining who causes air pollution - and who breathes that pollution - this research is just the beginning."
The other co-authors on this paper are Joshua Apte at the University of Texas at Austin; Andrew Goodkind at the University of New Mexico; Nicholas Muller at Carnegie Mellon University; Kimberley Mullins at Lumina Decision Systems; David Paolella at the University of Washington, and Stephen Polasky, Nathaniel Springer and Sumil Thakrar at the University of Minnesota.