Jonathan Lambert, NPR, March 11, 2019
Scientists and policymakers have long known that black and Hispanic Americans tend to live in neighborhoods with more pollution of all kinds, than white Americans. And because pollution exposure can cause a range of health problems, this inequity could be a driver of unequal health outcomes across the U.S.
A study published Monday in the journal PNAS adds a new twist to the pollution problem by looking at consumption. While we tend to think of factories or power plants as the source of pollution, those polluters wouldn’t exist without consumer demand for their products.
The researchers found that air pollution is disproportionately caused by white Americans’ consumption of goods and services, but disproportionately inhaled by black and Hispanic Americans.
“This paper is exciting and really quite novel,” says Anjum Hajat, an epidemiologist at the University of Washington who was not involved in the study. “Inequity in exposure to air pollution is well documented, but this study brings in the consumption angle.”
Hajat says the study reveals an inherent unfairness: “If you’re contributing less to the problem, why do you have to suffer more from it?”
The study, led by engineering professor Jason Hill at the University of Minnesota, took over six years to complete. According to the paper’s first author Christopher Tessum, a postdoctoral researcher at the University of Washington, the idea stemmed from a question at a conference.
It’s a big, complicated issue, but studying it could address a fundamental question: Are those who produce pollution, through their consumption of goods and services, fairly sharing in the costs?
“The different kinds of data, by themselves, aren’t that complicated,” says Tessum. “It’s linking them where things get a little trickier.”
The researchers generated maps of where different emitters, like agriculture or construction, caused PM2.5 pollution. Coal plants produced pockets of pollution in West Virginia and Pennsylvania, while agricultural emissions were concentrated in the Midwest and California’s central valley. “We then tied in census data to understand where different racial-ethnic groups live to understand exposure patterns,” says Hill.
To do that, the researchers actually worked backwards, following consumer spending to different sectors of the economy, and then ultimately to the main emitters of air pollution.
Consider one major contributor to emissions: agriculture. Consumer expenditure surveys from the Bureau of Labor Statistics provide detailed data on how much money households spend in various sectors of the economy, including food.
These data gave the researchers an idea of how much blacks, Hispanics, and whites spend on food per year. Other expenditures, like energy or entertainment, are also measured. Taken together these data represent the consumption patterns of the three groups.
After accounting for population size differences, whites experience about 17 percent less air pollution than they produce, through consumption, while blacks and Hispanics bear 56 and 63 percent more air pollution, respectively, than they cause by their consumption, according to the study.
“These patterns didn’t seem to be driven by different kinds of consumption,” says Tessum, “but different overall levels.” In other words, whites were just consuming disproportionately more of the same kinds of goods and services resulting in air pollution than minority communities.
While more research is needed to fully understand these differences, the results of this study raise questions about how to address these inequities.