Pollution from other states causes more air quality-related deaths in Massachusetts than almost any other state in the country, according to a new study from researchers at MIT.
The study tracked emissions of air-polluting compounds in all 48 contiguous states, researchers said. They found that half of the air pollution generated inside a state is carried by wind into other states.
Researchers said this increased the risk of early death for people no matter how clean their own state is. According to their findings, more than half of air quality-related deaths in the United States are caused by emissions from other states.
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“It’s not necessarily just the adjacent state (that is affected by air pollution), but states over 1,000 miles away that can be affected,” said Steven Barrett, study leader and associate professor of aeronautics and astronautics at MIT. “Different kinds of emissions have a different kind of range.”
The research, published Wednesday in the journal Nature, was compiled by MIT’s Laboratory for Aviation and the Environment and the MIT Joint Program on the Science and Policy of Global Change.
“Efforts to mitigate air pollution have focused mainly on the relationship between local emission sources and local air quality. Air quality can also be affected by distant emission sources, however, including emissions from neighbouring federal states,” the study said. “This cross-state exchange of pollution poses additional regulatory challenges.”
Current air pollution regulation allows largely for local regulation of local sources, Tracey Holloway, a professor at University of Wisconsin-Madison who studies air quality but did not work on the study, told Bloomberg News. “Each state can do a ton to control air pollution within their own borders, but they only have bits and pieces to address air pollution coming from other states.”
In 2018, about 950 Massachusetts residents died from air pollution from other states, according to the study. Only New York and New Jersey saw more deaths caused by out-of-state air pollution that year.
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Another 1,504 deaths in Massachusetts were caused by emissions generated inside of the state in 2018, researchers said. These emissions also traveled into other states and caused 427 early deaths of residents in those states.
Researchers said electric power generation likely caused most deaths that were related to air pollution. In 2005, for example, more than 75% of air pollution-related deaths in the U.S. were caused by power plant smokestacks in states the victims did not live in, according to the study.
Researchers noted that early deaths related to air pollution in the U.S. went down 30 percent between 2005 and 2018. They said new regulations, like the Environmental Protection Agency’s Clean Air Act, have contributed to this change.
“Regulators in the U.S. have done a pretty good job of hitting the most important thing first, which is power generation, by reducing sulfur dioxide emissions drastically,” Barrett said. “Now it’s looking like other emissions sectors are becoming important. To make further progress, we should start focusing on road transportation and commercial and residential emissions.”
Michael Brauer, an environmental health specialist at the University of British Columbia in Canada who was not involved in the study, agreed the findings show that work needs to be done to reduce pollution from smaller sources like commercial buildings and homes.
Decreases in early deaths from pollution from larger sources like power plants, he told The New York Times, are “a result of the effectiveness of federal regulations.”
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Barrett and other researchers tracked emissions from electric power generation, homes, businesses, and different types of transportation using data from 2005, 2011, and 2018.
Using various models, they tracked where these emissions were carried to in the United States and determined a state population’s chance of early death based off of how much out-of-state air pollution they had been exposed to, researchers said.
“We can figure out, for example, how much [air polluting] emissions from road transportation in Arizona in July affects human health in Texas, and we can do those calculations instantly,” Barrett said.
Researchers said northern Midwest states send more emissions to other states than they receive, partly because winds usually sweep them away. States on the East Coast, however, receive more emissions from other states than they produce because they are in the path of these winds.
Researchers hope the study will someday help prevent air pollution-related deaths across the country.
“There’s a big archive of data we’ve created from this project,” Barrett said. “We think there are a lot of things that policymakers can dig into, to chart a path to saving the most lives.”
Caroline Enos can be reached at caroline.enos@globe.com. Follow her on Twitter @CarolineEnos.