Saturday, March 24, 2018
Consumer, industrial products now a major urban air pollution source

Consumer, industrial products now a major urban air pollution source

New study finds big impact from paints, pesticides, perfumes as vehicle emissions drop

Chemical products like household cleaners, pesticides, paints and perfumes that contain compounds refined from petroleum now rival motor vehicle emissions as the top source of urban air pollution, according to a surprising NOAA-led study.

Far more fuel is consumed each year than petroleum-based compounds in chemical products—about 15 times more by weight, according to the new assessment, which is based on data collected in 2012. Even so, lotions, paints and other products contribute about as much to air pollution as the transportation sector does, said lead author Brian McDonald, a CIRES scientist working in NOAA’s Chemical Sciences Division.

What’s more,  these products produce about twice as many tiny particles that can damage people’s lungs as the transportation sector, researchers found. McDonald and colleagues from NOAA and several other institutions reported their results today in the journal Science.

“As transportation gets cleaner, those other sources become more and more important,” McDonald said. “We’ve reached that transition point already in Los Angeles. The stuff we use in our everyday lives can impact air pollution.”

For the new assessment, the scientists focused on volatile organic compounds or VOCs. VOCs can waft into the atmosphere and react to produce either ozone or particulate matter—both of which are regulated in the United States and many other countries because of health impacts.

Scientists captured this image of Los Angeles from a research aircraft that was part of a mission to study the region’s air quality and climate-related challenges. Among the findings now emerging from that effort: Emissions from common household and industrial products including perfumes, pesticides and paints now rival motor vehicle emissions as the top source of the city’s air pollution. Photo: Raul Alvarez, NOAA.

Pollution sources then, and now

Since adoption of the Clean Air Act in 1970, air quality efforts have focused a great deal of effort on controlling pollution from the transportation sector by adopting  pollution-limiting changes to engines, fuels and pollution control systems. McDonald and his colleagues reassessed urban air pollution sources by cataloging recent chemical production statistics compiled by industries and regulatory agencies, by making detailed atmospheric chemistry measurements in Los Angeles air, and by evaluating indoor air quality measurements made by others.

The scientists concluded that in the United States, current air pollution inventories underestimate the amount of VOCs emitted by consumer and industrial products by a factor of two or three, while at the same time overestimating the contribution from vehicular sources. 

The disproportionate air quality impact of chemical product emissions is partly because of a fundamental difference between those products and fuels, said NOAA atmospheric scientist Jessica Gilman, a co-author of the new paper. Fuel systems minimize the loss of gasoline to evaporation in part to maximize energy generated by combustion,” she said. But common products like paints and perfumes are literally engineered to evaporate. “Perfume and other scented products are designed so that you or your neighbor can enjoy the aroma,”Gilman said. “You don't do this with gasoline.”

The team was particularly interested in how those VOCs end up contributing to particulate pollution.

Indoor air poses problems

McDonald and his colleagues found that they simply could not reproduce the levels of particles or ozone measured in the atmosphere unless they included emissions from volatile chemical products. In the course of that work, they also determined that people are exposed to very high concentrations of volatile compounds indoors, which are more concentrated inside than out, said co-author Allen Goldstein, from the University of California Berkeley.

“Indoor concentrations are often 10 times higher than outdoors, and that’s consistent with a scenario in which petroleum-based products provide a significant source to outdoor air in urban environments,” said Goldstein.

The new assessment does find that the U.S. regulatory focus on car emissions has been very effective, said co-author Joost de Gouw, a CIRES chemist. “It’s worked so well that to make further progress on air quality, regulatory efforts would need to become more diverse,” de Gouw said. “It’s not just vehicles any more.”

For more information, please contact Theo Stein, NOAA Communications, at 720-391-0163 or by email at
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