Household products like hairspray, paint, and disinfectants are increasingly contributing to summertime air pollution in cities, yet most urban air-quality models fail to account for them, according to new research
The study, conducted by Colorado State University, the University of Minnesota, and Purdue University, found that volatile organic compounds (VOCs), potentially hazardous gases often linked to indoor air pollution, are significant urban pollutants during summer months. These emissions come not only from personal care products, paints, solvents and cleaners, but also from building materials themselves.
Delphine Farmer, a chemistry professor at CSU’s College of Natural Sciences who helped lead the research, said: ‘We found that volatile chemical products … and even building materials themselves were major emissions from the city in summer. These sources are important but are not accurately included in current models that cities and states use to predict and reduce air-quality events.’
The researchers collected measurements in an urban area of Long Island, New York, during both summer and winter. Their data showed a clear seasonal shift, with vehicle emissions dominating wintertime air pollution, and summertime pollution being largely fed from chemical products and residential sources.
Co-author Dylan Millet, an atmospheric chemistry expert at the University of Minnesota explained: ‘Vehicles on U.S. roadways have become much cleaner burning. As a result, other less-studied sources of urban air pollution are becoming more relevant. Many of these emerging pollution sources increase when it is hotter, meaning they are liable to increase during heat waves and as climate warms.”
The researchers point out that temperature dependence is a critical gap in current air-quality models. Because cities rely on these models to issue advisories and enact regulations, missing these sources could lead to flawed decision-making.
To gather their data, the team used a method called ‘eddy covariance’ [a technique explained in this ground-breaking research from last year] from a cellular tower, combining wind and chemical measurements to directly determine emission rates for a wide range of pollutants. The approach is rarely used in urban field studies because it requires complex measurement setups and sampling from heights well above surrounding buildings.
Michael Vermeuel, the paper’s first author and an assistant professor at Purdue University, said; ‘We used the most direct method available for measuring emissions from the urban surface… to determine what pollutants were actually being emitted and where they were coming from. Few field experiments have done this in urban environments, and it revealed a broad chemical fingerprint that changed substantially between summer and winter.’
The findings suggest that as vehicles become cleaner, policymakers must broaden their focus to include consumer products and building materials, especially as rising temperatures amplify their emissions. Without updated models, cities may struggle to protect residents from increasingly complex summertime air pollution.
Photo: Jesus Kiteque
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