New study demonstrates dangers of gas appliances to public health

By Josh Lee

We are in a time of profound change and isolation, but among all those changes, there is one that I have been particularly fixated on: all my friends are now baking bread. My social media feeds have been overwhelmed with photos of wonderful (and sometimes lumpy) loaves and rolls, and during this time the comfort of a fresh baked loaf of bread or the catharsis of kneading dough is more than welcome. But I can’t help but also notice that there is an insidious danger in this bounty of boules and baguettes. Baking requires long and extended use of the oven, and more often than not, at least for my peers, that means using outdated, gas-powered ovens in tiny apartments with limited ventilation. A new study by UCLA has highlighted the impacts of gas appliances on indoor air quality and public health, and they are damning: respiratory illness, cardiovascular diseases, and premature death, especially among the most vulnerable, including children, the elderly, low-income renters and communities of color.

While we know the climate benefits of moving away from gas to clean, zero-emission electric appliances, there have been few studies focused on the health impacts. Thankfully, the new study out of UCLA’s Fielding School of Public Health, titled “Effects of Residential Gas Appliances on Indoor and Outdoor Air Quality and Public Health in California,” helps provide insight on those impacts at a time when we are focused more than ever on public health. The nature of COVID-19 means that those who have certain respiratory illnesses, including asthma, are more vulnerable to the novel coronavirus, and this study helps reinforce our understanding that gas appliances can be drivers for increased respiratory illness and COVID susceptibility. The UCLA study was commissioned by the Sierra Club.

Gas appliances emit several pollutants, including carbon monoxide (CO), nitrogen oxides (NOx, including nitrogen dioxide (NO2)), fine particulate matter (PM), and formaldehyde, which have been linked to various acute and chronic health effects, including respiratory illness, particularly in children. UCLA researchers found that after cooking for one hour with a gas stove and oven, peak levels of NO2 inside the kitchen are so high they exceed both state and national outdoor acute air-quality standards in more than 90 percent of the homes modeled.

Inhaling NO2 is extremely dangerous, especially for children and the elderly, who are more susceptible to lung disease. Children exposed to elevated levels of NO2 are more susceptible to lung infections and allergies, and are at increased risk of lowered IQ, learning deficits, and asthma. In fact, a 2013 study found that children who grow up in a home with a gas stove are 42 percent more likely to develop asthma than those who don’t.

The report estimates that if all gas appliances in California homes were immediately replaced with electric alternatives, the reduced air pollution would result in approximately 350 fewer deaths, 600 fewer cases of acute bronchitis, and 300 fewer cases of chronic bronchitis every year. This is equal to approximately $3.5 billion in health benefits over the course of each year.

This is also an issue of equity and environmental justice, with impacts falling hardest on the most vulnerable among us. Renters and low-income residents are particularly at risk from gas appliances, with the UCLA study finding that “concentrations of CO and NO2 resulting from gas cooking are the highest for apartments”. UCLA researchers found that after an hour of cooking on a gas stove, 98 percent of smaller apartments had peak levels of NO2 that exceeded these state and national air-quality standards. In other words, the air quality inside nearly every apartment was so bad that it would be illegal if measured outside. Renters also often have old and unmaintained appliances in households, smaller and overcrowded residences where air pollution can reach higher concentrations, and limited ability to control appliance choices or afford maintenance. 

Emissions from gas appliances are harmful under normal circumstances, and they are even more frightening in light of a recent Harvard study that determined that “a small increase in long-term exposure to fine particulate matter leads to a large increase in the COVID-19 death rate.” This shows how critical it is that we address community electrification as part of our response to COVID-19.

While we have seen some fascinating impacts of this pandemic on outdoor air quality, indoor air quality has remained largely undiscussed. As we respond to this public health crisis, we have an unprecedented opportunity to not just return to the status quo, but to build a better, safer future, inside and out. Decarbonizing our homes and communities is key in not only mitigating our emissions, but in protecting our communities’ health. A just response to the pandemic by our cities, state, and country must recognize that.

Some immediate actions we can take as individuals to mitigate the impacts of gas appliances include: opening windows, using the exhaust range hood, installing carbon monoxide detectors, or switching out our gas run appliances with electric induction technology. However, we have greater power collectively pushing our representatives to respond appropriately. Policymakers at all levels must set science-based guidelines for indoor air quality, provide incentives for electrification, and join communities like Berkeley and San Jose in moving forward with gas-free building ordinances.

Learn more about building decarbonization by joining one of our upcoming webinars and build the skills to advocate for your city to adopt gas-free and electric-ready ordinances. For more information or to get involved, reach out to Melissa Yu at

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