After I read the news brief warning Americans about the dangers of cooking with natural gas, I decided to research the subject in more depth. What I found was definitely something for consumers and home builders to consider when they’re shopping for new home appliances. The news brief reported that gas stoves emit potent greenhouse gases that have an irritant effect human bronchial tubes and lungs. The harmful effects are most noticeable in adults with pre-existing lung disease, but there is concern that these emissions can cause normal lungs to become fibrotic or emphysematous.
Last year, there were rumors circulating that the U.S. government was soon going to issue a ban on gas stoves. Officials in the know quickly denied this and stated such claims “are absurd.” However, the state of California has issued a ban on gas stoves because much of the research on gas stoves was done in California and a sympathetic legislature agreed with the findings. Nationally, such a ban would be a big deal because an “estimated 38% of U.S. homes have gas-fueled cooking appliances (ranges, cook tops, and ovens)” which means a ban would affect more than “40 million homes” and families.
Natural gas used for cooking contains methane (CH4) and propane. “The combustion of both gases generates multiple pollutants of public health concern, including nitrogen dioxide (N02). Nitrogen dioxide is a “greenhouse gas,” and we all know greenhouse gases are the subject of ire and activism by climate change advocates. Gas stoves are of concern because they have the potential to release high concentrations of NO2 into a confined space (your kitchen) in close proximity to children and adults. Concentrations of NO2 are measured in parts per billion (PPB). A “normal” acceptable level is 53 PPB or less. The combustion of methane during cooking generates NO2 levels in excess of 100 PPB. A level of 150 PPB, or greater, has been reported to cause death from pulmonary edema. So this is a serious concern.
When gas appliances had continuously-burning pilot lights, emissions were produced constantly. Now, however, gas appliances are required to have electronic ignition systems, and emissions, though still present, are a fraction of what they were with pilot lights.
Many studies have shown that certain situations put people at greater risk than others. During scientific studies, nitrogen dioxide levels were measured in the summer, in the winter, in urban and rural areas, indoors and outdoors, and with the stove turned on and turned off. Comparisons of risk were then determined. The results were interesting:
In both winter and summer months, indoor NO2 levels were “significantly” higher in rural areas than urban homes. Is that because rural people cook more or because of environmental factors? I don’t know.
In winter, outdoor levels of NO2 were significantly higher in urban and lower income areas.
Outdoor NO2 levels were low (2.4 PPB) in summer and higher (3.9 PPB) in winter in urban areas.
Indoor and outdoor NO2 levels were significantly higher in any home with a gas stove than any home with an electric stove. That makes sense.
Gas stoves emit methane both when the stove is on, and also, when it is off “highlighting the potential for gas stoves to continuously contribute to indoor air pollution and to greenhouse gases even when not in use….Leakage is due to loose and leaky pipe fittings and connectors….methane leakage can occur even with newly installed gas stoves.” I think this data is confusing, but it points out that natural gas cooking produces enough harmful pollutants to be a public health risk not to be ignored.
Adequate ventilation and “a ventilation hood with adequate air flow can decrease NO2 concentrations by up to 95% when cooking is limited to the back cooktop burners.” That is rather limiting and inconvenient, and I suspect easily forgotten. The natural tendency is to use the front burners which are closer to the cook. High efficiency particulate air filtration devices to absorb gases have been shown to lower indoor NO2 concentrations “to a modest extent.” But data suggests that families who don’t use range hoods or who have poor ventilation can surpass dangerous levels of NO2 within a very few minutes.
As stated in the news brief, gas stove emissions are known to trigger asthma flare-ups and have been linked to chronic obstructive pulmonary disease and pulmonary fibrosis. Exposure to NO2 causes “chest tightness, shortness of breath, wheezing, cough, and an increase in rescue inhaler use.” What is in question is whether the cause of human lung injury is NO2 directly, or is it other activated pollutants that are the real culprits. One study has found a positive association between nitrogen dioxide and COPD.
“We do know with certainty…..gas stoves are a source of indoor air pollution and contribute to greenhouse gas emissions, and there is a precautionary imperative to protect those who are susceptible….” Increasingly, there are calls to ban the installation of new gas stoves, but opponents and proponents are at odds on the right course to follow. Some call for stricter regulation of gas stoves and measures to reduce or stop leakage. Others want an outright ban. The answer is somewhere in between. Could gas stoves be sold/installed with a warning label like has been on cigarette packages for decades warning consumers to use a gas appliance at their own risk? It is a fact, however, that the only way to eliminate this problem is replace all gas stoves with electric stoves. That will effectively eliminate the phrase, “I’m cookin’ with gas!” but it will also impact many aspects of modern culture.
I don’t think this concerns people enough to inconvenience themselves even a little. Most people like the ease and temperature variation control afforded by gas burner cooking. And the lung problems caused by gas stove emissions haven’t hit close enough to home for people to demand a change, and we have limited data on how likely lung problems are to occur. Not everybody quit smoking even though they were warned there is clear evidence of the multiple harms from tobacco and nicotine, and cigarettes were not banned completely. And not everyone will trade their gas stove for an electric range. Some folks will still want the flexibility of gas cooking. Unless you have a family member whose asthma is triggered by natural gas emissions, you won’t be inclined to cook with an electric stove.
Is the impact on the indoor environment enough to warrant a ban? I don’t know. But I do know that “annual methane emissions from all gas stoves in U.S. homes have a climate impact comparable to the annual carbon emissions of 500,000 cars.” The world is not perfect so total elimination of greenhouse gases is nearly impossible, but the United States has been much better and more compliant with environmental controls than many other countries of similar size and population.
References: Paulin LM, Samet JM, Rice MB. Gas Stoves and Respiratory Health: Decades of Data, but Not Enough Progress Ann Am Thor Soc 2923 Dec;20(12):1697-1699.
Lebel ED, Finnegan CJ, Ouyang Z, Jackson JB. Methane and NO, Emissions from Natural Gas Stoves, Cooktops, and Ovens in Residential Homes Environ Sci Technol 2022 Feb;56(4):2529-2539.
Wi C, Gent J, Bublitz JT, et al. Paired Indoor and Outdoor Nitrogen Dioxide Associated with Childhood Asthma Outcomes in a Mixed Rural-Urban Setting: A Feasibility Study J Prim Care Community Health 2023 Jan-Dec;14.
Zhang Z, Wang J, Lu W Exposure to Nitrogen Dioxide and a chronic obstructive pulmonary disease in adults: a systematic review and meta-analysis. Environ Sci Pollut Res Int 2018 May;25(15):15133-15145.
Yoon HY, Kim SY, Kim OJ, Song JW Nitrogen dioxide increases risk of disease progression in idiopathic pulmonary fibrosis Respirology 2023 Mar;28(3):254-261.
Cui F, et al. Air pollutants, genetic susceptibility and risk of incident idiopathic pulmonary fibrosis. Eur Respir J 2023 Feb 2;61(2):2200777.
