Junk the gas range and go electric for improved indoor air quality and better health, a new report from the Rocky Mountain Institute (RMI) says.
Gas stoves are a major contributor to indoor air pollution, pushing levels of nitrogen dioxide and carbon monoxide to levels that would be unlawful under standards that apply to outdoor air, according to the report. Homes with gas stoves have nitrogen dioxide levels that are as much as four times higher than homes with electric stoves, with chances of children developing asthma 24% to 42% higher.
The report, “Gas Stoves: Health and Air Quality Impacts and Solutions,” was developed in collaboration with Physicians for Social Responsibility, Mothers Out Front, and the Sierra Club. It draws on a number of studies already on the record.
Although a “robust body of scientific research” shows that pollutants released by gas stoves can adversely affect health and worsen respiratory conditions, indoor air pollution is mostly unregulated, the report says. While establishing permitted pollution levels outdoors and in the workplace, the federal government has established no standards for small particulates and carbon dioxide inside the home.
Everyday use of a gas stove can elevate nitrogen dioxide concentrations to levels well above those set for outdoor air by U.S. and world health organizations. According to the report, for example, baking a cake or roasting meat in the oven pushes N02 concentrations to two or three times the 100 parts per billion limit set by the Environmental Protection Agency (EPA) for outdoor air. Even boiling water pushes levels of the pollutant to nearly double the EPA standard.
The potential for poor health is especially disturbing for children, the report says, because they have higher lung surface-to-body weight ratios and smaller bodies, and because their respiratory and immune systems are immature.
Health impacts may include increased risk of childhood asthma, learning deficits, wheezing, coughing, difficulty in breathing and greater risk of lung infections. Low-income households also may be at higher risk and show more cases of asthma than would be expected.
“Regulators have largely failed to act despite the fact that data accumulated for decades is publicly available,” the report said.
Gas use is widespread
About half of all U.S. homes use gas for heating, cooking, and other energy needs, with some 35% cooking primarily with gas. On average, people spend nearly 90% of their time indoors, where air quality is often worse than it is outdoors.
“The US EPA states that indoor levels of pollutants may be two to five, and occasionally more than 100 times higher than outdoor air pollution levels,” RMI says. “While outdoor emissions of six criteria air pollutants have decreased by 74 percent since the passage of the Clean Air Act in 1970, no federal regulations or guidelines have addressed indoor air pollution.”
Other findings and recommendations include:
- Older, poorly maintained, and poorly vented stoves are linked with higher N02 emissions. Stove with pilot lights are another source of contaminants.
- Even small increases in short-term exposure to N02 can increase the risk of asthma in children. A threshold for safe levels of the pollutant have not been established, and documented health effects occur at levels “well below” the EPA’s outdoor air standards.
- Higher concentrations of people living in smaller housing units contribute to higher levels of N02, making the problem more acute in lower-income, multifamily buildings. In some cases, low-income families use gas ovens for heat because central heating systems are inefficient or broken.
- Gas water heaters, furnaces, and clothes dryers must be vented to the outdoors, but no uniform venting requirements exist for gas stoves. Even in states where gas stoves must be vented, there are no comprehensive standards to make sure a ventilation fan is effective or is turned on automatically when pollution levels get too high.
- Exhaust hoods that recirculate air rather than vent it outdoors do not uniformly remove pollutants, especially from burners at the front of the stove. Even with hoods that vent to the outdoors, performance varies widely. “For units that have been tested,” the report notes, “most fail to capture more than 75 percent of pollutants and those that do are often noisy.”
Electric cooking is the cleanest possible cooking option, the authors say, because they do not emit high levels of combustion pollutants and are inherently cleaner than gas appliances.
Replacing a gas stove with an electric stove decreased N02 concentrations by 51% in one study and helped to reduce the contaminant throughout the house, not just in the kitchen.
Citing standards adopted in Canada in 2015, the RMI study made a number of policy suggestions. They included an appeal to the Consumer Product Safety Commission to set science-based guidelines for nitrogen dioxide and carbon dioxide, and require manufacturers to certify that any new gas stove won’t expose people to harmful levels of the pollutants.
“It’s time to address the root cause of much of the home’s indoor air pollution: the gas stove,” the report says. “Moving from gas to electric stoves can help protect the most vulnerable populations, including children and the elderly.”
Scott Gibson is a contributing writer at Green Building Advisor and Fine Homebuilding magazine.