The chemicals found in items you use every day — like your shampoo, perfume and cleaning products — now have as much of an impact on air pollution as vehicle emissions. That's according to a new study led by the National Oceanic and Atmospheric Administration (NOAA) that also includes researchers from several universities.
We use 15 times more petroleum as fuel than as ingredients in consumer and industrial products, researchers said, yet the amount of chemical vapors released into the atmosphere through scented products is roughly the same as through fuel emissions.
Those vapors are volatile organic compounds (VOCs). They react with sunlight to form ozone pollution, and the researchers found they also react with various chemicals in the atmosphere to create fine particulates in the air.
"As the transportation sector gets cleaner, these other sources of VOCs become more and more important," lead author Brian McDonald, a NOAA scientist, said in a statement. "A lot of stuff we use in our everyday lives can impact air pollution."
Measuring the air
The study specifically looked at pollution over Los Angeles. (Photo: Andrius K/Shutterstock.com)
For the study, which was published in the journal Science, researchers specifically studied air pollution over greater Los Angeles. The team couldn't reconcile measurements made over the area with estimates of transportation emissions. So they reassessed sources of air pollution by combing through recent chemical production statistics and evaluated indoor air quality measurements that were made by other groups.
The team found that the VOC levels emitted by chemical products are actually two or three times more than earlier estimates, which had also overestimated emissions from vehicles. As an example, the Environmental Protection Agency estimates that about 75 percent of VOC emissions come from vehicles and about 25 percent from chemical products. The new study says the sourcing is closer to 50-50.
The lopsided air-quality impact is due to an inherent difference between scented chemical products and fuels.
"Gasoline is stored in closed, hopefully airtight, containers and the VOCs in gasoline are burned for energy," said NOAA atmospheric scientist Jessica Gilman, co-author of the study. "But volatile chemical products used in common solvents and personal care products are literally designed to evaporate. You wear perfume or use scented products so that you or your neighbor can enjoy the aroma. You don't do this with gasoline."
Though the focus of the study was Los Angeles, the researchers believe the results are applicable to all major urban areas.
The results suggest that people can have an impact on air quality, and not just through their choice of transportation.
"What’s exciting about this work is that it shows that everyday consumer choices can have an impact on air quality in the U.S.," Christopher Cappa, professor of civil and environmental engineering at UC Davis and a co-author on the paper, said in a statement.
Your personal care rush hour
In a separate study, scientists springboarded off this research to study specifics of the morning emissions in Boulder, Colorado, and Toronto. They detailed VOC emissions from personal care products in both cities. These products evaporate quickly and emit decamethylcyclopentasiloxane, known as D5 or siloxane. Siloxane is added to products to give them a silky feeling.
They found that the emission rate of siloxane is similar to the emission rate of benzene, which comes from vehicles.
They discovered that chemicals in health care products contribute just as much to VOC emissions as fuel, at least in the early part of the day.
“We detected a pattern of emissions that coincides with human activity: People apply these products in the morning, leave their homes, and drive to work or school. So emissions spike during commuting hours,” said lead author Matthew Coggon, a scientist at the University of Colorado Boulder working in the NOAA Earth System Research Laboratory, in a statement.
The new study, published in Environmental Science & Technology, found that both siloxane and benzene declined throughout the day, then peaked again during the evening commute.
“In this changing landscape, emissions from personal care products are becoming important,” Coggon said. “We all have a personal plume, from our cars and our personal care products. Our team wants to learn more about these understudied sources of pollution.”
Editor's note: This story was originally published in February 2018 and has been updated.