Household spray cleaners and other common petroleum-based products used around the home, such as paints, pesticides, printer ink and perfumes, now contribute as much outdoor air pollution in some urban areas as car and truck emissions, according to a study published last week in the journal Science.

The specific pollutants cited in the study are known as volatile organic compounds (VOCs).  These chemicals contribute to the formation of ozone and to the fine airborne particulates in smog. VOCs have been linked to many short- and long-term health problems, including nose and throat irritation, nausea, headaches and damage to the lungs, liver, kidney and central nervous system. Some are also suspected or known to cause cancer.

Last year, a study in The Lancet estimated that air pollution killed 6 million people a year worldwide and that the greatest health risk came from VOCs.

Efforts to control tailpipe emissions have steadily reduced the amount of VOCs released into the atmosphere by motor vehicles. The new study suggests, however, that as cars and trucks become cleaner, the VOCs responsible for our cities’ air pollution are increasingly likely to be coming from consumer products.

Currently, the Environmental Protection Agency estimates that motor vehicle emissions make up about 75 percent of VOCs in urban areas, while chemical products make up the other 25 percent. According to the new study, the ratio is more like 50-50 in Los Angeles — and perhaps in other urban areas.

That finding is quite surprising, given that only about 5 percent of fossil fuels are used in non-transportation-related products.

How could products that use such a small percentage of petroleum be responsible for half of urban particulate pollution? 

“Gasoline is stored in closed, hopefully airtight containers, and the VOCs in gasoline are burned for energy,” explains Jessica Gilman, one of the authors of the study and a scientist with the U.S. National Oceanic and Atmospheric Administration (NOAA), in a press release. “But volatile chemical products used in common solvents and personal care items 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.”

“Indoor concentrations are often 10 times higher indoors than outdoors, and that’s consistent with a scenario in which petroleum-based products used indoors provide a significant source to outdoor air in urban environments,” says Allen Goldstein, another co-author and a professor of environmental science at the University of California Berkeley, in the same press release.

To reach their findings, the scientists used a number of sources of information, including data from various industries and regulators on the chemicals found in different products, indoor air quality measurements made by other researchers, and air-chemistry samplings taken in Los Angeles.

What you can do

If more progress is going to be made on improving air quality in metropolitan areas, the regulatory focus will have to expand to include consumer chemical products — including common ones used in the home, the study’s authors conclude.

Some consumer products have already been altered to reduce VOC emissions, such as the switch from oil-based paints to water-based ones.

But consumers don’t have to wait for the regulators, at least to limit their exposure to the chemicals (which don’t always smell) in their homes. Here are some tips from the Minnesota Department of Health:

Source Control:

• Only buy what you need when it comes to paints, solvents, adhesive and caulks. Unused chemicals stored in the home can sometimes “leak” and release VOCs into the air.
• Store unused chemicals in a garage or shed where people do not spend much time.
• Dispose of unused chemicals that are stored in your home or garage. Check with your city or county for household hazardous waste collection sites.
• Consider purchasing low-VOC options of paints and furnishing. 

Ventilation and Climate Control:

• When buying new items, look for floor models that have been allowed to off-gas in the store. Solid wood items with low emitting finishes will contain less VOCs than items made with composite wood.

• Increase ventilation by opening doors and windows. Use fans to maximize air brought in from the outside.

• Keep both the temperature and relative humidity as low as possible or comfortable. Chemicals off-gas more in high temperatures and humidity.

• Try to perform home renovations when the house is unoccupied or during seasons that will allow you to open doors and windows to increase ventilation. 

Of course, increasing the ventilation in your home is only going to release more of the VOCs from your household products into the air in your community. To reduce outdoor VOC pollution you’ll need to use brands and items that don’t contain those chemicals. One place to start is with cleaning products. The Environmental Working Group (EWG) has produced a helpful guide to healthy cleaning products, which you can find on its website.

FMI: The study in Science can be read in full on the journal’s website.