Unhealthy particulate matter comes from, among other things, factories, cars, construction, and fossil fuel power plants. A new study analysing 14 major sources of air pollution shows that in the U.S., they disproportionately affect people of colour.
For the study, published in Science Advances on Wednesday, researchers used an air quality model to estimate the PM2.5 emitted from 5,434 sources listed in the Environmental Protection Agency’s 2014 National Emissions Inventory. They then grouped these sources into 14 different sectors, including industry, construction, residential gas combustion, agriculture, and commercial cooking, and mapped out who lives closes to each of the sectors of pollution.
People of colour experience greater-than-average exposures from 12 sectors of particulate matter pollution that cause 75% of overall exposure. Blacks and Hispanics bore even more of a burden than other people of colour, with sectors behind 78% and 87% of pollution in the study taking a heavier toll on them than average. White people, on the other hand, that figure dropped to 40% of pollutants. This applied to both rural and urban areas and across income levels.
“Before we did all the research, we had this initial sense, as is often the case with environmental problems, that there would be some really bad actors that might be the efficient ones to target if you want to solve the air pollution injustice problem. We thought you could look for especially unjust sources,” said Joshua Apte, a pollution scientist at the University of California, Berkeley who co-authored the study. “But what we were really struck when we tried to find when we sort of looked at our results, is how basically every major source sector in the US. disproportionately impacts … people of colour.”
As the study notes, this disproportionate exposure is no accident — it happens by design. Research shows both the public and private sector are more likely to build all kinds of polluting infrastructure in and around areas where more nonwhite people live.
That’s in large part due to the long history of policies to enforce racial segregation in the U.S. For instance, areas that were subjected to redlining — the discriminatory lending practice where Black people were denied home loans and insurance due to their neighbourhoods being labelled “hazardous” — still see higher rates of respiratory problems tied with air pollution. The particles — which are generally a byproduct of burning fossil fuels — are super small, standing at 100 times thinner than a strand of human hair. Beyond respiratory impacts, PM2.5 is particularly dangerous because when humans inhale it, the particles can penetrate our blood and get carried into our brains, causing a host of other issues.
Christopher Tessum, an assistant professor of civil and environmental engineering at the University of Illinois Urbana-Champaign and study co-author, said redlining is just one example of discriminatory zoning practices.
“An important thing to consider is that [redlined] areas only include a very small per cent of the total population because the geographic area of most urban areas has greatly expanded since the 1930s, and that the effect that we see is just as large in current urban area extents as it is in the historically red-lined areas,” he wrote in an email. “So although documented historical racism and oppression are an important factor, our results suggest that areas that are more recently built aren’t on average any better in terms of environmental justice.”
The disparity is also because of the geographical areas where corporations and governments choose to site infrastructure, and where different groups of people tend to live. For instance, agricultural emissions are one of the few pollution sources that affect white people more than average. That pollution comes from farms, which are most often placed in rural areas that tend to be whiter than urban ones. By contrast, there are more cars and construction projects in big cities, where more nonwhite people tend to live.
Since this disparity was created by many policies and practices, there’s no silver-bullet solution to fix it. That’s especially true because of how U.S. policy is written.
“The way that the Clean Air Act works is that we have ambient air quality standards, and you’re in violation as a general as a metropolitan area if your average levels of pollution fall above that standard,” Apte said. “Most areas in the U.S., by definition of the way we have our laws, meet our air quality standards, thankfully.”
As standards get stricter, Apte said, air pollution overall is decreasing as entities fall into compliance. “But if the sources are disparately sited in communities of colour at of every spacial scale … tightening standards simply lowers the total levels pollution, but doesn’t get rid of the baked-in disparities,” he said. “To me, that means you need to think about where these sources are. Until we get to a world with no pollution, making that burden more equally shared is probably going to be an important component of the solution.”
That doesn’t mean, of course, that we should start building new gas plants and highways in white neighbourhoods to up pollution levels. Rather, Apte said, the U.S. could find ways to incentivise companies and municipalities to pay particular attention to reducing pollution in heavily impacted communities.
As the authors note, though their findings are remarkably stark, they’ll likely come as no surprise to community groups who have been fighting air pollution for decades and know that people of colour are more likely to suffer the effects of it.
“Probably the best way to do this is to listen to the people that live in the communities that are most affected, and organisations that represent them,” said Tessum.
Apte also added that while working with grassroots organisers is a great idea, we shouldn’t put the burden on them to fight against air pollution but rather support them both locally and in the push for holistic policies.
“When you have a problem that’s so systemic, there’s got to be a call for centralised federal action,” said Apte.