Soap, paint chemicals found in LA smog

LOS ANGELES—When it comes to air quality, the products you use to smell nice or scrub your kitchen could be just as bad as the car you drive. A new study of the air around Los Angeles finds consumer and industrial products now rival tailpipe emissions in creating atmospheric pollutants.

The findings, published Thursday in the journal Science, reveal a shift in the balance of polluting power in cities — one that might prompt researchers and regulators to focus more on a wide range of consumer and industrial goods, such as hairspray, paint and deodorant.

Air-pollution exposure is a leading cause of health problems worldwide. Among risk factors to human health, it ranks fifth behind malnutrition, poor diet, high blood pressure and tobacco, according to a report last year in the journal Lancet.

Much of the stuff in air pollution forms from reactions with volatile organic compounds, or VOCs, a wide range of carbonbased chemicals that easily escape into the air and that humans produce in huge amounts.

In the past, car exhaust was responsible for much of those man-made VOCs. That’s been especially true in Los Angeles, a freeway-laced land of long commutes that a few decades ago was wreathed in dark, heavy layers of smog.

But as restrictions on tailpipe emissions have tightened and automotive technology has improved, the amount of VOCs has dropped and the air has cleared. (Cars still produce tons of carbon dioxide, an invisible greenhouse gas that scientists say is contributing to global warming.) Scientists wanted to see what that meant for L.A.’s air-pollution profile.

Study co-author Christopher Cappa, an environmental engineer at the University of California, Davis, and his colleagues looked at data on the contents of outdoor air to see what pollutants they would find. They soon noticed that levels of certain VOCs, such as ethanol and acetone, were far too high to be explained by vehicle emissions alone.

The scientists went looking for those sources. They found that many common products, including pesticides, coatings, paints, printing inks, adhesives, cleaning agents and personalcare products such as body spray and hairspray, were full of volatile organic compounds that could be released into the air.

Given that many of these VOC-containing products are used indoors, the scientists checked previous research on the air quality of interior spaces. Sure enough, the indoor concentrations of VOCs from these products were roughly seven times higher than they were in ambient air.

Cappa and his colleagues believe some of those compounds were probably leaking out of those buildings and polluting the greater environment.

VOC-filled products such as deodorant and hand sanitizer account for only about five per cent of the oil and natural gas used in Los Angeles, and yet, consumer and industrial products emit roughly the same level of VOCs as fuel-burning vehicles, since they’re intended to evaporate.