An anonymous reader quotes a report from The Guardian: Household cleaners, paints and perfumes have become substantial sources of urban air pollution as strict controls on vehicles have reduced road traffic emissions, scientists say. Researchers in the US looked at levels of synthetic "volatile organic compounds", or VOCs, in roadside air in Los Angeles and found that as much came from industrial and household products refined from petroleum as from vehicle exhaust pipes. The compounds are an important contributor to air pollution because when they waft into the atmosphere, they react with other chemicals to produce harmful ozone or fine particulate matter known as PM2.5. Ground level ozone can trigger breathing problems by making the airways constrict, while fine airborne particles drive heart and lung disease. Writing in the journal Science, De Gouw and others report that the amount of VOCs emitted from household and industrial products is two to three times higher than official US estimates suggest. The result is surprising since only about 5% of raw oil is turned into chemicals for consumer products, with 95% ending up as fuel.