Embargoed: Not for Release Until 2 p.m. (14:00) U.S. Eastern Time on Wednesday, 07 October 2026.
Products such as hairspray, paint and household disinfectants are increasingly causing summertime air pollution – and cities aren't accounting for it, which makes air-quality advisories and regulations harder to enact, new research from Colorado State University, the University of Minnesota and Purdue University shows.
In fact, volatile organic compounds – the potentially hazardous gasses emitted by these products and often associated with indoor air pollution – are notable urban pollutants in the summertime, the research published in Science Advances finds.
“We found that volatile chemical products – think personal care products, paints, solvents and cleaners – and even building materials themselves were major emissions from the city in summer,” said Delphine Farmer, a CSU chemistry professor who helped lead the research. She works in the Department of Chemistry within CSU’s College of Natural Sciences.
“These sources are important but are not accurately included in current models that cities and states use to predict and reduce air-quality events,” Farmer said.
The research paper describes measurements taken in an urban area of Long Island, New York, during both summer and winter. The data reveals that vehicle emissions were the source of most wintertime air pollution, yet summertime air pollution largely arose from other sources, including chemical products and residences.
"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,” explained co-author Dylan Millet, a professor and expert in atmospheric chemistry at the University of Minnesota. “Many of these emerging pollution sources increase when it is hotter, meaning they are liable to increase during heat waves and as climate warms."
Current air quality models don’t account for the temperature-dependent pollution, the paper notes. That means city and state agencies could be missing key information in their decision-making frameworks for managing and regulating air pollution.
The research data was collected from a cellular tower using a method known as “eddy covariance,” which combines wind and chemical measurements to directly determine emission rates for a wide variety of pollutants.
The approach is rarely used in urban field studies because of the complex measurement requirements and the need to sample from a height that is well above that of the surrounding buildings.
While most urban air quality studies measure the concentrations of pollutants to understand what is in the air, this eddy covariance technique combined with machine learning tools allowed the team to better understand both pollutants and their sources.
“We used the most direct method available for measuring emissions from the urban surface, combining detailed chemical monitoring with wind measurements to determine what pollutants were actually being emitted and where they were coming from,” said Michael Vermeuel, the paper’s first author and an assistant professor at Purdue University. “Few field experiments have done this in urban environments, and it revealed a broad chemical fingerprint that changed substantially between summer and winter."
Science Advances
Surface temperatures drive strong seasonality in urban reactive carbon emissions
7-Oct-2026