Did I Turn Off the Stove? Yes, but Maybe Not the Gas

The debate over the effects of gas-powered appliances on human health and climate change has been added to by a new report.

The small study was based on the measurement of stove emissions from 53 homes in California and estimated that they emit between 0.8 and 1.3 percent of the natural gas they consume as unburned methane, a potent greenhouse gas. Three-quarters of the emissions occur when the devices are not in use, and this could be a sign of leaking connections to gas service lines.

The study estimated that emissions from stoves in the United States could have the same effect on the planet as half a million gas-powered cars.

Eric D. Lebel is a senior scientist at the nonprofit research institute PSE Healthy Energy and the lead author of the study.

He said that more and more evidence supports the idea that stoves are damaging health and climate at the same time.

In blue states like California and Massachusetts, more and more people are moving away from gas-powered cooking and heating. New York City banned gas hookups in new buildings. Most of the red states have banned cities from restricting gas use, often with the support of natural gas companies and utilities that see electric vehicles as a threat to their bottom lines.

There were more than 40 million gas stove in American households in 2015, the last year for which there is detailed data from government surveys. 13 percent of America's greenhouse gas emissions come from homes and buildings.

If methane isn't burned, it can warm the Earth more than carbon dioxide over a 20-year period. Ground-level ozone pollution can cause breathing problems and other health issues.

Efforts are underway to plug thousands of inactive, methane-spewing oil and gas wells across the country, as methane leaks from oil and gas installations have attracted increasing attention in recent years. Rob Jackson, an earth scientist at the university, said that less research has been done on emissions inside residences.

Plastic sheets were used to seal off kitchens in private homes and properties for sale or rent. They found that if you ignite a burner on a gas stove, it will emit the same amount of methane as if you leave it on and burn it for 10 minutes. They found that gas ovens emit methane at a higher rate than cooktop burners, because they periodically ignite and extinguish their main burner to maintain the set temperature.

The researchers did not try to find the source of the leaks, but they did measure emissions over five to 10 minutes when the stove was off.

The natural gas supply chain has a tendency to leak.

There were no gas leaks that were of a concentration that would cause an explosion.

Older stoves did not perform differently from newer ones when it came to methane emissions. pricier models did not beat cheaper ones.

They would like to have done more tests in homes owned by people who can't afford to replace old appliances. They said this would help capture the disproportionate impacts of gas emissions on low-income families.

Scientists don't fully understand why levels of methane in the atmosphere have gone up in recent years, according to a researcher who did not work on the new study.

More methane ends up in the air than in the ground. Home appliances are just one piece of the puzzle.