I have a confession to make. I am a lung doctor who hosts a podcast and a website with the slogan “Don’t light things on fire and breathe them into your lungs.” However, I regularly light a fire in my home to cook for my family. I have a gas stove. When my husband and I were buying our first home together, I was excited to move on from the electric coil stove I had at our rented apartment, and had heard about gas stove superiority. I didn’t give it much thought, had learned nothing about gas stoves during my fellowship training in pulmonary medicine, and was happy to sign up for what I thought would be a better cooking experience. I’m sure I was also subconsciously influenced by the name “natural” in natural gas. After starting Air Health Our Health, I started to wonder a great deal more about these stoves, and have come to worry more about their potential health concerns and how to mitigate them. Maybe you are in the same boat? Do you have a gas stove in your own home? If so, hopefully this post and podcast episode will be helpful for you!
I was joined on today’s podcast by Dr. Laura Paulin MD, MHS of Dartmouth College. After graduating from the Johns Hopkins School of Public Health with a Masters in Health Sciences in Environmental Health focusing on Risk Sciences and Public Policy, she then went to medical school at the University of Massachusetts. She completed her Residency in Internal Medicine at Montefiore Medical Center and her fellowship in pulmonary and critical care medicine at Johns Hopkins University. In addition to caring for patients and teaching future doctors, she researches the impact of environmental exposures on lung health, with extensive experience in the field of air pollution exposure assessment. She has studied the impact of indoor air quality in homes, for example evaluating the use of solid fuel in rural Appalachia, as well as studying home interventions aimed at decreasing indoor nitrogen dioxide concentrations. She has studied indoor particulate matter and NO2 exposures and asthma outcomes as well as their impact on others with lung disease and pregnant women. She has published multiple articles in leading respiratory and environmental journals, and currently serves on the Environmental Health Policy Committee of the American Thoracic Society.
Today on the podcast, we talk about several of the studies in which she has participated. In one study, they evaluated 5 to 12 year olds with asthma living in homes with gas stoves and measured NO2 levels in the home and outside, and evaluated symptom and inhaler use. They found higher NO2 the longer the gas stoves were running, which was of particular concern in the winter.
One of the most concerning symptoms of poor asthma control is worsened symptoms at night or need for night time inhaler use. This is one of the things that we ask about at almost every asthma visit to ensure that baseline disease is under reasonable control. In this study, they found that higher levels of NO2 were associated with an increased need for inhaler use at night. Multiple studies have found similar poor control of airway disease related to NO2, including one showing kids growing up in multifamily housing with gas stoves had over double the risk of wheezing and shortness of breath and four times the risk of chest tightness.
It is hard to determine what will work to improve indoor air quality and what we should recommend to patients. Investments to clean up the air can cost money, so we would want to make sure we are recommending interventions that work. As I have come to learn, indoor air is the wild west in terms of regulation, and there are many interventions that are sold to clean up indoor air which may have dubious success or potentially be harmful. Dr. Paulin worked on a very practical study in which they randomized around 100 homes with gas stoves to either have the gas stoves replaced, install a ventilation hood, or use a HEPA filter with activated carbon. They lay out the benefits and trade-offs in this table with approximate costs at study time.
This was a great study in real-world conditions, and showed that the hoods surprisingly did not seem to help much either in the kitchen or in the bedroom. I know that my own hood often makes a lot of noise when it is on high, so I sometimes want to turn it down. Replacing the stove showed the biggest improvement, followed by the use of an air filter with HEPA and activated charcoal. The effects were biggest for stoves that had a pilot light, since homes with gas stoves with pilot lights emitted more NO2.
The improved effect of replacing gas appliances with electric ones is also consistent with another study that showed replacing gas heaters in schools with electric heaters cut asthma attacks, difficulty breathing, and chest tightness in children by more than half. It is interesting how much combustion is intimately involved in our everyday lives. So what have I done with this information and the growing burden of evidence in general that NO2 can be harmful to health, even at levels below legal thresholds? I also find the data about methane emissions and other harmful byproducts of natural gas in homes concerning.
We have tried to move away from using our current stove as much as possible- switching to an electric kettle to boil water, doing more pressure cooking, etc, and we ultimately plan to replace our gas stove. Honestly, I can’t help regretting the choice to get a gas stove in the first place. As always, this issue brings up the large inequities that often impact the quality of the air we breathe. Replacing a gas stove is expensive. I am a fortunate individual with a large kitchen, and hopefully, a reasonably powered hood, although my conversation with Dr. Paulin now makes me concerned that my hood may not be as protective as I hoped, especially in the way I was using my stove. However, many of my patients live in smaller multi-family with gas stoves that are likely not ventilated as well, if at all, and they and children growing up in those homes are likely exposed to higher levels of NO2 than children in larger single family homes like mine. I also worry about workers who are exposed to gas stoves in even greater amounts, such as those working in busy kitchens at restaurants, etc. Here in Portland, OR, we also have a lot of food trucks, and I always worry about the quality of ventilation in them for people standing over a stove for hours on end.
Listen to the podcast episode to learn more, and review the references below for more details.
TLDR= Don't Light Things on Fire and Breathe them into your Lungs
To Do– especially if a member of the Twitchy Airways Club
1- If you are looking for a new home or thinking of a change of kitchen, electric is likely a better choice than gas for the health of your family and community.
2- If you already have a gas stove, think through your options. If you have the means to replace it or are due to replace your stove, consider changing to an electric stove. If you can’t, make sure to ventilate as best you can. If you have a hood, run it on its highest setting, ensure it ventilates to the outdoors, and try to use the back burners. Consider using a HEPA filter with a carbon component to absorb NO2.
3- Contact your county, state and national representatives and advocate for policies to reduce the use of gas in indoor settings or help people transition away from gas while keeping energy and cooking costs clean and affordable. This is likely a complex issue that will require multiple stakeholders, but it is important to be a voice for health.
4- Consider a donation to the American Thoracic Society, who works hard to support research into clean air and to inform policy around the importance of clean air.
References
More Information:
Berkeley Lab- Indoor Environments – “Indoor Air Pollutants Sources and Exposures.”
