Understanding Cooking with Gas: Indoor Air Quality and Health
There has been a lot of media attention in the past few months on gas stoves and health. Here’s a breakdown of what the research shows, what you can do today to improve your indoor air quality, and steps to electrify going forward.
New research provides a better understanding of the potential health and environmental impacts of both unburned gas (from small leaks when the stove is off) and burned gas (when the stove is in use).
Unburned and leaked gas from stoves
When does gas leak from stoves?
Research has shown that gas stoves leak gas. A study that surveyed 53 stoves found that over 75% of methane leaked in a 24-hour period was released when the stove was off. Another 25% was released due to incomplete combustion while cooking or when turning the stove on and off.
Methane emissions released while igniting or switching off a gas burner were found to be equivalent to 10 minutes of cooking. The total emissions of methane from gas stoves in the US is estimated to be the equivalent of the annual carbon dioxide emissions from 500,000 cars. The US Environmental Protection Agency does not currently include any estimates for methane emissions from incomplete combustion from gas appliances or indoor leaks in the estimate of total methane emissions contributing to global warming.
Presence of contaminants in gas
A study by the Harvard School of Public Health, PSE Healthy Energy, and HEET, in Massachusetts identified over 296 unique volatile organic compounds (VOCs) present in small quantities in the gas supply that comes to our stoves, including 21 different known hazardous air pollutants. Two of these pollutants, benzene and toluene, are known carcinogens that we are commonly exposed to in differing amounts from cigarette smoke, gasoline, forest fires, paints, varnishes, nail polish, glues and adhesives.
Research on emissions from burned gas
Cooking with gas produces nitrogen oxides (NOx) and particulate matter (PM2.5). If a stove is not well ventilated, these emissions can affect indoor air quality. Research suggests that a poorly ventilated gas stove can produce levels of NO2 exceeding the 1-hr EPA standard for outdoor air (100 ppb NO2) within a few minutes of turning on a stove. Consumer Reports conducted a lab test that found high levels of NOx near the stove when the hood was not turned on.
Both NOx and PM2.5 are associated with increased risk of asthma and triggering asthma symptoms. A meta-analysis in 2013 of 41 international studies suggests that children living in a home with gas cooking have a 42% increased risk of having current asthma. A re-analysis published in December 2022 based on US data, suggests that the attributable risk of asthma in children in homes with a gas stove that is not well vented is 12%.
More research is still needed to understand actual exposure and risk from indoor air-quality with an inadequately vented gas stove.
What can you do to improve your indoor air quality today?
When cooking with a gas stove, you can reduce your exposure by making sure that the hood above your stove is turned on and is ventilating to the outside. If you don’t have a hood, or your hood only recirculates into the kitchen, open a window. Be sure to do this every time you cook, whether using a gas stovetop or gas oven. This will help to reduce any indoor exposure to nitrogen oxides and particulate matter that are produced when cooking with gas.
If you are planning to replace your stove, consider replacing your gas stove with an induction-electric stove. Trying a portable induction cooktop is a good way to learn about the benefits of cooking with induction, hands on!
When you decide to replace your gas stove (or propane stove), know that residents in Massachusetts can receive a $500 rebate from Mass Save towards replacing their gas or propane stove with an induction stove. Income eligible residents can receive up to $840 rebate from Inflation Reduction Act funds towards replacing a gas or propane stove with either electric or induction. The cost of an induction stove has come down over the past few years, with popular models currently available starting around $1500.
