Air freshener. Shaving cream. Bug spray. Nearly everything under your sink or in your medicine cabinet is a source of air pollution. Scientists and regulators have known this for years, but a new study from UC Davis and the University of Colorado concludes that consumer products are bigger polluters than previously thought.
When engineering professor and study co-author Chris Cappa began measuring precursors of smog called volatile organic compounds in the air above Pasadena in 2010, he expected that the bulk of the emissions would come from cars and trucks. After all, that’s what regional air regulators estimated in their pollution inventories for Southern California.
Instead, he and his co-authors at University of Colorado Boulder and the National Oceanic and Atmospheric Administration found the opposite: consumer products made up almost 40 percent of the human-generated VOCs in the atmosphere, compared to only 33 percent from cars and trucks.
“VOCs in the atmosphere are actually much more of a balance now between cars and trucks and things like consumer products,” Cappa said. “This was absolutely surprising.”
VOCs are gases that waft off of liquids like gasoline,or solids like sticks of deodorant. When they hit the atmosphere and are baked by sunlight, they turn into ozone or smog. Greater Los Angeles has the worst smog problem of any metro area in the United States. During peak smog season last year, May through October, there were just 70 days of clean air. The region’s dirty air causes over 1,500 people to die prematurely.
“Anything you smell inside, and that smell disappears, it usually went outside,” Cappa said. “And that can have a real impact on air quality.”
Cappa and his co-authors say state and local air regulators are likely underestimating VOC emissions from consumer products and overestimating the contribution of cars and trucks. Over time, vehicles have gotten a lot cleaner due to tailpipe emissions standards and catalytic converters. But, they say, emissions from consumer products remain a significant source of smog-forming pollution.
Joseph Calavita, who manages the consumer products team for the California Air Resources Board, said the findings speak to the state’s success in cracking down on vehicle emissions more than an indictment of consumer product regulations.
California began regulating tailpipe emissions in 1966 – 23 years before CARB passed its first VOC emission standard on antiperspirant and deodorant in 1989. Since then, the agency’s rules have expanded to cover 130 different products, and under state law, manufacturers can be penalized for selling items that exceed emissions standards. In the past five years, CARB has issued at least $1.3 million in fines annually for violating consumer products emissions standards.
“We recognize consumer products are a large and important component of smog,” Calavita said.
Currently, CARB is finalizing its own survey of VOC emissions from consumer products sold in California, a survey that used different methodology than the UC Davis study. Preliminary results from CARB's survey show VOC emissions from consumer products are “modestly higher” than current estimates, but “I’m not sure we fully agree that they’re as big as motor vehicles,” Calavita said.
Suzanne Paulson, an atmospheric scientist at UCLA who studies urban air pollution, said quantifying VOC emissions from consumer products is just plain hard.
“When you have a can of paint open, the emissions can be very high. When they’re stored in a cabinet they can be a lot lower,” she said. “So just in general, assembling high quality emissions inventories is a challenging task.”
UC Davis study co-author Cappa said he hoped his work would inspire people to feel like they have more control over something as abstract as regional air quality. While there is not currently a list of which household products have lower VOC emissions than others, Cappa has a simple recommendation: use less.