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New study confirms that gas stoves are bad for your health

Just using them for an hour pushes pollution above legal limits.

A new study from the UCLA Fielding School of Public Health confirms what we have been saying for years: gas stoves and appliances are bad for your health. Lead researcher Yifang Zhu says, “California’s state agencies often focus on greenhouse gas emissions and climate change impacts, but there has been much less focus on how fossil fuel use in household appliances can adversely impact indoor air quality and public health.”

The study starts off by reminding us of the link between air pollution and susceptibility to COVID-19:

California currently faces a global pandemic in which a rapidly spreading coronavirus disease, COVID-19, can cause severe respiratory illness and even death. New evidence suggests that a small increase in long-term exposure to fine particulate matter (PM2.5 ) leads to a large increase in the COVID-19 death rate; this further establishes the substantial value in protecting the population from the respiratory vulnerability caused by widespread air pollution .

The biggest indoor air problems came from cooking with gas, as most water heaters and furnaces are direct vented to the exterior, creating its own set of problems in CO2 and other emissions. Indoor air pollutants included Carbon Monoxide, Nitrogen Oxide, Nitrogen Dioxide and particulate matter. Nitrogen Dioxide was the worst, “exceeding the level set by both the chronic California Ambient Air Quality Standards (CAAQS) ambient annual average limit of 57 micrograms per cubic meter (μg/m3), and the acute National Ambient Air Quality Standards (NAAQS, set by the US EPA) 1-hour limit of 188 μg/m3 or 100 parts per billion (ppb). “

PM2.5 levels were significant too, but it's important to note that “studies measuring PM2.5 emissions found that increases attributed solely to gas kitchen appliances (with no cooking of food involved, though sometimes a pot of water was heated) were negligible.” The bulk of PM2.5 emissions come from the food, not the gas.

The problems of pollution from cooking are magnified by the issue of exhaust hoods, which I have called The most screwed up, badly designed, inappropriately used appliance in your home.

Gas stoves often lack adequate exhaust ventilation. The low-rise residential building ventilation code ASHRAE 62 .2 requires the installation of range hoods in kitchens, with minimum airflow and maximum noise levels, but it is estimated that only half of new homes in the United States comply with this standard. Furthermore, a study of California homes, using data from a real estate website, approximated that 47% of homes had combination microwave/range hoods, which do not meet the airflow and noise level requirements of ASHRAE 62.2, while 7% of homes had no range hoods at all.

Hoods are not appropriately sized or installed and fewer than 35 percent of California residents bother to even turn them on, mainly due to excessive noise. Many also have filters that are hard to remove and clean. “It is important to note that increased awareness of the need for ventilation during cooking and encouragement of range hood use may reduce exposures to pollutants emitted by combustion appliances for those with properly sized, installed, and maintained hoods.”

Another factor is residence size: In smaller residences, the indoor pollutants are more concentrated.

Peak concentrations in the kitchen resulting from usage of stoves and ovens simultaneously, by pollutant [(a) CO and (b) NO2 ] and housing type .Peak concentrations in the kitchen resulting from usage of stoves and ovens simultaneously, by pollutant [(a) CO and (b) NO2 ] and housing type ./Public Domain

As the graphs show, CO and NO2 levels are highest in apartments, CO is below recommended levels and NO2 well above. This is serious stuff.

Studies have found a robust association between NO2 from gas cooking and increased risk of respiratory illness in children, such as asthma, wheezing, and other respiratory symptoms. NO2 exposure from gas appliances is implicated in many other respiratory symptoms, including cough, lung obstruction, and shortness of breath. Women may be at higher health risk from NO2 exposure, due to greater susceptibility and higher frequency of cooking compared to men. Research suggests that due to the widespread use of gas for cooking, NO2 exposure from gas appliances has a substantial public health impact, particularly in children. The respiratory effects of acute NO2 exposure more broadly include decreased lung function, asthma exacerbation, and increased risk of respiratory infection. Short-term NO2 exposures above the CAAQS 1-hour standard are associated with lung inflammation, particularly in individuals with asthma or chronic obstructive pulmonary disease (COPD).

It goes on. “Studies have observed a relationship between chronic NO2 exposure and all-cause, cardiovascular, respiratory, and lung cancer mortalities, with greater risks among populations with preexisting diseases .” Yet we continue to allow people to put gas stoves in their giant open kitchens. And don't get me started on the dangers of PM2.5 and UFP or ultrafine particles.

Meanwhile, outside:

Using the EFs developed in this study’s indoor air quality analysis, and assuming all indoor emissions are transported to the outdoor environment, we find that approximately 12,000 tons of CO and 15,900 tons of NOX were emitted to outdoor air from the use of residential gas appliances in California in 2018. If all residential gas appliances were immediately replaced with clean electric alternatives, the reduction of outdoor NOX and PM2.5 would result in 354 fewer deaths, as well as 596 fewer cases of acute bronchitis and 304 fewer cases of chronic bronchitis annually in California.

It's time to cut off the gas.

This is a hard sell when gas is so cheap compared to electricity, and when so many people prefer to cook with gas, even though induction ranges have grown in popularity. But it's clear that we don't just have a carbon crisis, we have a health crisis, and we shouldn't have gas stoves in our homes, let alone in apartments and tiny houses.

There should also be building code enforcement on the rules for exhaust hoods; they should be properly sized and placed, should not be forehead-greaser recirculating hoods, and should be interconnected to the stoves so that you can't cook without them going on. This should be required for gas or electric stoves; both produce particulate pollution from cooking. We are killing ourselves and our kids with these things.

Just using them for an hour pushes pollution above legal limits.