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\nEach year, a form of air pollution known as PM\u00a02.5 contributes to 100,000 premature deaths in the United States and 4 million globally.<\/p>\n
Microscopic airborne particles known as PM 2.5 contribute to 100,000 premature deaths in the United States each year. A new University of Notre Dame study finds that 40 percent of these deaths can be attributed to pollution that crosses state lines, highlighting the impact of the problem and pinpointing which states are responsible.<\/p>\n
\nEach year, a form of air pollution known as PM\u00a02.5 contributes to 100,000 premature deaths in the United States and 4 million globally.<\/p>\n
The study, published in Environmental Research Letters<\/a>, provides a tool to quantify responsibility for PM 2.5 pollution, a type of fine particulate matter. It comes amid renewed debate over pollution regulations in the United States. In January, the Environmental Protection Agency said it will stop calculating the\u00a0economic value of health benefits<\/a> \u2014 including lives saved and health care costs avoided \u2014 from air pollution rules targeting ozone and PM 2.5.<\/p>\n The research was co-authored by Paola Crippa<\/a>, assistant professor in the Department of Civil and Environmental Engineering and Earth Sciences<\/a> and Richard (Drew) Marcantonio<\/a>, assistant professor of environment, peace and global affairs in the Keough School of Global Affairs<\/a>, along with Wenxu Liao<\/a>, a doctoral student in the Department of Civil and Environmental Engineering and Earth Sciences<\/a>.<\/p>\n \u201cOur analysis gives states an evidence-based way to demonstrate when cross-state pollution exceeds safe thresholds and threatens public health,\u201d Marcantonio said. \u201cRather than relying solely on an economic evaluation, policymakers can use clear data on health risks to guide decisions that protect vulnerable residents and communities.\u201d<\/p>\n The new study translates the concept of an airshed \u2014 a geographical area where air moves together as a single unit, similar to hydrology\u2019s concept of a watershed \u2014 into a practical framework that regulators around the world can use.<\/p>\n \u201cOur study introduces a simpler, data-driven framework that policymakers and regulators can readily adapt,\u201d Crippa said. \u201cThis is an important improvement upon previous studies, which have had limited scalability and adaptability.\u201d<\/p>\n Findings underscore pollution\u2019s unequal impact<\/p>\n The study highlights the inequality of pollution in the United States. Researchers found that:<\/p>\n The percentage of premature deaths attributed to cross-state PM\u00a02.5 pollution has remained constant at approximately 40 percent since 1998, even though air pollution has fallen by 35 percent in the same time period.<\/p>\n More than half of U.S. states are net exporters of air pollution; roughly a third are net zero contributors, meaning they are neither importers nor exporters; and the remainder, less than a fifth, are net importers.<\/p>\n Florida stands out as the largest exporter of cross-state pollution (affecting Georgia and the Carolinas), followed by Vermont and Iowa.<\/p>\n Exporters include a number of states across the Upper Midwest, the Mid-Atlantic and the Southeast \u2014 including Wisconsin, Michigan, Indiana, Ohio, Kentucky, West Virginia, Virginia, Tennessee, Mississippi, Alabama and South Carolina \u2014 as well as California, Oregon and Washington on the West Coast.<\/p>\n Instead of relying primarily on complex chemical transport models, the authors drew on the concept of an airshed to design a simpler, data-driven approach. They highlighted concentrations of PM 2.5 that exceed established safety thresholds and mapped how these particulates, pushed by prevailing winds, cross state lines, harming communities in which they did not originate.<\/p>\n The research builds upon previous work<\/a>, which has documented that major air polluters are more likely to be located near a state\u2019s downwind borders than other types of polluters. This dynamic allows states to economically benefit from industry while avoiding the health issues that come with it.<\/p>\n \u201cOur findings underscore the unequal distribution of both health risk and responsibility across state lines,\u201d Marcantonio said.<\/p>\n Informing policy to address pollution<\/p>\n Crippa and Marcantonio want their work to inform policy both in the United States, where legal challenges are the main barriers to regulation, and in other global contexts, where a lack of resources is the main barrier.<\/p>\n \u201cUltimately, we want to provide an evidence-based approach to protecting public health and supporting human dignity,\u201d Marcantonio said.<\/p>\n In the United States, air pollution regulation faces legal and political challenges. Traditionally, it has been decentralized and the Clean Air Act\u2019s \u201cGood Neighbor\u201d provision has been the strongest regulatory tool. In 2024, the Supreme Court paused<\/a> an updated Environmental Protection Agency plan aimed at strengthening that provision and addressing shortcomings in state plans.<\/p>\n In lower-resource contexts outside the United States, regulators often have limited access to complex, resource-intensive air quality models. But they face a similar public health problem: pollution that crosses political boundaries and harms other communities.<\/p>\n Whether the regulatory challenges are legal or technological, Crippa and Marcantonio said their work can provide a more timely and complete picture of pollution\u2019s impact, furnishing policymakers with data that can help them protect vulnerable downwind communities.<\/p>\n The researchers are extending their work globally through a multi-year project co-led with Danielle Wood, director of the Notre Dame Global Adaptation Initiative<\/a>, focused on how pollution that originates in mega-cities affects other communities.<\/p>\n Funding for that work and the cross-state study was provided through a Notre Dame Strategic Framework Grant;<\/a> additional support for the cross-state research came from Notre Dame\u2019s Environmental Change Initiative<\/a> and the Lucy Family Institute for Data & Society<\/a>.<\/p>\n This work aligns with Notre Dame\u2019s Just Transformations to Sustainability Initiative<\/a>, a University-wide effort to build a sustainable future where people and nature flourish together.<\/p>\n \u201cOur research can inform policy and help regulators prioritize permitting, monitoring and enforcement activities,\u201d Marcantonio said. \u201cUltimately, we want to provide an evidence-based approach to protecting public health and supporting human dignity.\u201d<\/p>\n Crippa is the principal investigator for the Atmospheric Modeling Group<\/a>, part of Notre Dame\u2019s College of Engineering<\/a>, and Liao is also affiliated with the group. Marcantonio is affiliated with the Business Ethics and Society Program<\/a> and the Deloitte Center for Ethical Leadership<\/a> in Notre Dame\u2019s Mendoza College of Business<\/a>; with the Environmental Change Initiative<\/a> and Lucy Family Institute for Data & Society<\/a>; and with the Keough School\u2019s Kellogg Institute for International Studies<\/a> and Kroc Institute for International Peace Studies<\/a>.<\/p>\n How PM 2.5 harms public health<\/p>\n PM 2.5 affects the lungs, heart and brain, contributing to cancer, COPD, stroke and cognitive decline.<\/p>\n It disproportionately affects vulnerable communities worldwide.<\/p>\n Pregnant women, children, seniors\u00a0and people with asthma, diabetes, obesity\u00a0or kidney disease face higher risks.<\/p>\n Originally published by Josh Stowe at keough.nd.edu<\/a> on Jan. 28.<\/p>\n![\"Two](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/01\/interstate_air_pollution.webp.webp\")
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\nRegulators can use new research by Paola Crippa and Drew Marcantonio to measure responsibility for deadly air pollution that crosses political boundaries.<\/p>\n