Gas Stoves and Indoor Air Quality – Fresh Air on a Hot Topic

by Sandhya Sethuraman and Maria A. di Landro

gas stove
Emissions from gas stoves cause poor indoor air quality and health problems

Urged by scientists’ findings on the links between gas stove use and their contribution to indoor pollution and increased risk of respiratory illnesses, the CPSC (Consumer Product Safety Commission) has recently begun to consider a ban on gas stoves. More than 40 million U.S. households rely on gas stoves to cook with, but many are not aware of their negative impacts on indoor air quality and climate: natural gas appliances release nitrogen oxides, particulate matter, formaldehyde, and carbon dioxide into the air, and they can leak methane, even when not in use. Higher indoor pollution levels, as a consequence of gas stove emissions, can have various respiratory impacts, including asthma, coughing, wheezing, and difficulty breathing. In this article, we provide more details on what academic research has found, including the estimated fraction of current childhood asthma associated with gas-stove use in each state. We also discuss how various states are already taking initiative and are working to move away from new gas stove installation. Using New York as a case study, this article describes their new bill that effectively bans the use of gas stoves in the construction of new buildings starting in 2024 and what the response from the public has been. In the meantime, there are various measures the public can take to protect themselves from gas stove emissions.

What’s the controversy?

A torrent of information, data, and dissent followed the initial CPSC announcement — scientists urged reform while political parties made the debate about consumers’ freedoms. To make some sense of the dialog: 

  • In December, Senator Cory Booker (D-NY) and Representative Don Beyer (D-VA) published a report strongly urging the CPSC to consider a ban on gas stoves. They argued that gas stoves emit high levels of pollutants like nitrogen dioxide (NO2), carbon monoxide (CO) and fine particulate matter (PM2.5). 
  • Amid debates surrounding gas stoves, consultants with ties to the American Gas Association have criticized research which linked gas stoves to childhood asthma.
  • Voices on the right have argued that removing gas stoves from homes is an infringement on their basic rights. Senators Cruz and Manchin introduced legislation in early February to bar the CPSC from using federal funding to ban gas stoves, arguing that it “constitutes government overreach.” 
  • The American Gas Association also pushed back against the ban, arguing that housing would become more expensive as “electric homes require expensive retrofits.”

The resulting debate became clear: ban gas stoves in future buildings and transition to electric stoves instead, or continue as we always have? 

What’s happening right now? (NYC Case Study)

Currently, over 70 percent of greenhouse gas emissions in New York City comes from indoor air pollution in homes, but changing the internal piping and structures of old New York City buildings (retrofitting) is nearly impossible. Because many buildings went up before 1930, ripping out the existing infrastructure and effectively transitioning to more efficient and sustainable energy has proven to be a daunting task. 

In December 2021, New York’s City Council voted to ban the use of fossil fuels — and by extension gas stoves — altogether in new buildings. This law was scheduled to go into effect this year for structures shorter than seven-stories tall and in 2027 for all buildings. As of late, the council has asserted that co-ops and condominiums — newer, more modern buildings — are poised to make a difference in the short term if they make the necessary electrical upgrades and incentivize resident collaboration. 

Why gas stoves?

Simply put, gas stoves have gained attention because of how ubiquitous they are. Over one third of U.S. households — more than 40 million homes — cook with gas stoves. Natural gas appliances generate carbon dioxide, particulate matter, formaldehyde, and nitrogen oxides when natural gas is burned as a fuel, and leak methane into the air, often even when they are not in use. 

According to researchers at Stanford, gas stoves themselves have the same climate impact as about 500,000 gasoline-powered cars. Current EPA estimates are incomplete themselves, failing to account for the reality of gas pipelines (which leak much more than reported), and usually not including leakage within buildings at all. 

Additionally, the health impacts of having stoves in such close proximity to residents is well-understood. Because they are often central to homes, the respiratory impacts of pollutants — like asthma, coughing, wheezing and difficulty breathing — are often difficult to control and treat. People interact directly with their stoves (more so than other gas appliances), and the constant exposure to formaldehyde, carbon dioxide, nitrogen oxides, and methane can have long term health effects. 

The impacts of gas stoves are not equal either. As emphasized by Booker and Beyer, gas stoves have a larger impact on Black, Latino and low income households, who experience the “cumulative burden” of gas stove emissions and broader air quality impacts every day. In the global south, poor ventilation and living conditions mean that women and children are also disproportionately affected by indoor household emissions. 

What does the academic research say?

The push to “go electric” is backed by science, as the harmful byproducts of combustion are often emitted directly into the air indoors without proper ventilation systems in place. Indoor gas stove cooking is clearly connected to respiratory illness, and more than 12% of childhood asthma cases in the U.S. can be linked to gas stoves. 

A few key results: 

  • State-by-state differences in pollution levels from gas stoves, and therefore impacts, are correlated with their prevalence in the household, which means that a one-size-fits-all solution via blanket legislation is likely to fail. For example, Illinois experiences the highest childhood asthma burden from gas stoves (21.1%), followed by California (20.1%), New York (18.8%), Massachusetts (15.4%), and Pennsylvania (13.5%). Florida, where the demand for gas stoves is low, has the lowest burden (3%) (U.S. Energy Information Administration, via CNN).
  • There are existing benchmarks for “unsafe” pollution and residential exposure limits. For instance, Canada has a maximum residential exposure limit of 90 parts per billion (ppb) over an hour of exposure, and 11 ppb in the long term (> 24 hours) for NO2.
  • Gas stoves contribute different amounts of methane to the atmosphere based on when and how they are being used. A recent study published in Environmental Science & Technology found that 76% of the total methane emissions from stoves come from the steady-state off state (indicating significant leakage). 
Population attributable fraction of current childhood asthma associated with gas stove use in the U.S. From Gruenwald et al., Int. J. Environ. Res. Public Health 202320(1), 75;

What can you do?

  • Ventilate: exhaust streams are necessary in any kitchen; turning on a fan or opening a window is a good way to mitigate some of the negative effects of cooking on a gas stove. Many range exhausts don’t vent to the outside, but rather recirculate stove emissions back into the kitchen. Ventilation to the outside can greatly improve indoor air quality.  
  • Educate: launch education campaigns to better understand the risks associated with gas stoves, and how these can be minimized, especially for disadvantaged groups. 
  • Advocate: push for gas stoves to be sold with range hoods that meet mandatory performance standards, and for ventilation to the outdoors instead of recirculation. Additionally, gas stoves should be equipped with leak proof valves, which can be shut on and off to prevent methane exposure. 

Como los Incendios Forestales Agotan el Ozono Estratosférico

Una nube de pirocumulonimbos sobre el Parque Nacional Alpino, Australia, durante el “Verano Negro” de 2019-2020. Foto por Merrin Macleod, Wikimedia Commons

Después de los incendios forestales del “Verano Negro” de 2019-2020 en Australia, las medidas satelitales mostraron una disminución en la capa de ozono estratosférico. Durante este tiempo, los científicos relacionaron la disminución del ozono al humo de los incendios que penetraron la estratosfera. Sin embargo, el rol de las partículas de humo en la química del ozono aún no estaba claro. En un artículo publicado en Nature, Susan Solomon y sus colegas muestran que si las partículas de humo, que contienen materia orgánica oxigenada y agua, son líquidas en la estratosfera, son capaces de absorber gas HCl y acomodar reacciones químicas con otros gases del “depósito de cloro” como ClONO2 y HOCl. De esta manera, pueden provocar el agotamiento del ozono de manera muy similar a otras partículas estratosféricas. A medida que los incendios forestales grandes se vuelven más comunes como resultado del cambio climático, este fenómeno puede retrasar la recuperación del “agujero de ozono” estratosférico.

Proyecto Estudiantil: Prueba de la Eficiencia de Filtración de Algunos Tipos de Máscaras Comunes

por John Garcia Almazán, Maria Di Landro, y Sandhya Sethuraman

Unas mascarillas N95, KF94, y quirúrgica
Unas mascarillas N95, KF94, y quirúrgica. Foto por V.F. McNeill

Los Estados Unidos ha entrado en su tercer año desde el primer caso del coronavirus (COVID-19) confirmado en el país. Debido a las vacunas y otros medidas de salud pública, los casos de COVID-19 están bajo control hoy, pero la enfermedad sigue siendo altamente transmisible y, a veces, peligrosa. En este artículo, consideramos opciones de equipo de protección personal (EPP) en forma de máscaras faciales. Mascarillas que filtran bien la materia particular del aire que inhalamos son valiosas para prevenir infecciones. Teniendo en cuenta la escasez de máscaras y la presencia de mascarillas falsificadas en el mercado, es importante saber qué máscaras disponibles al público son realmente eficientes y efectivas para prevenir la propagación de COVID-19.

Realizamos varios experimentos en una cámara climática. Una muestra del material de diferentes marcas de máscaras estuvo expuesto a partículas pequeñas (10-800 nm). Seguimos las líneas directrices de NIOSH y probamos la filtración de partículas de NaCl a tres velocidades faciales diferentes, midiendo la eficiencia de filtración (la eficacia de las máscaras para proteger al usuario de estas partículas) en función del tamaño de las partículas.

Eficiencia de filtración del material de una mascarilla quirúrgica negra, medida para varios tamaños de partículas y tres velocidades faciales
Tipo de máscara5.3 cm/s10 cm/s15 cm/s
3M Aura (N95)979797
máscara quirúrgica negra889178
Dr. Puri KF94989595
Eficiencia de filtración general (%) para tres tipos de máscara facial, y tres velocidades faciales.

Observamos eficiencias de filtración consistentes con las especificaciones del fabricante para N95, KN95, KF94 y mascarillas quirúrgicas. Las máscaras N95 (3M Aura) demostraron la mayor eficiencia de filtración en todas las categorías, pero incluso el material de la máscara quirúrgicas negras o azules que generalmente se encuentran en oficinas y edificios públicos filtró la mayoría de las partículas.

En esta obra solo examinamos la filtración de muestras del material de mascarillas. En realidad, el ajuste de la máscara y el uso también son muy importantes para saber la eficacia de las máscaras para proteger al usuario.

How wildfires deplete stratospheric ozone

A pyrocumulonimbus cloud over the Alpine National Park, Australia, during the 2019-2020 fires
A pyrocumulonimbus cloud over the Alpine National Park, Australia, during the 2019-2020 fires. Credit: Merrin Macleod, Wikimedia Commons

After the Australian wildfires of the “Black Summer” of 2019-2020, satellite measurements showed a decrease in the stratospheric ozone layer. At the time, scientists connected the decrease in ozone to smoke from the fires that penetrated into the stratosphere, however, the role that smoke particles play in ozone chemistry was still unclear. In a paper published in Nature last week, Susan Solomon and colleagues show that if smoke particles, which contain oxygenated organic material and water, are liquid in the stratosphere, they are capable of absorbing HCl gas and hosting reactions with other “chlorine reservoir” gases such as ClONO2 and HOCl. In this manner, they can drive ozone depletion much like other stratospheric particles. As large wildfires become more common in a changing climate, this phenomenon may slow down the recovery of the stratospheric “ozone hole”.

For the article and more discussion:

New ventilation guidelines from Lancet COVID-19 Commission

Ventilation with clean air is essential for maintaining healthy indoor spaces. Insufficient ventilation increases the risk of transmitting airborne pathogens such as SARS-CoV-2 and also can lead to the buildup of indoor air pollution. The Lancet COVID-19 Commission on Safe Work, Safe School, and Safe Travel released recommendations November 18, 2022 for the minimum rates of ventilation with clean air for a workplace, classroom, or public transportation. These recommendations expand on the ASHRAE recommendations for minimum outdoor air ventilation and explicitly considers the combination of outdoor air ventilation with air filtration and air disinfection.

Table 1. from: Lancet COVID Commission Proposed Non-Infectious Air Delivery Rates for Reducing Exposure to Airborne Infectious Respiratory Diseases. November 2022.

The continued drumbeat of attention surrounding ventilation and healthy indoor air is without question a positive thing. However, a central problem is: How do schools and businesses meet these guidelines? Issues of funding aside, even knowing the ventilation rate on a room by room basis (“are we meeting guidlines or not?”) is a big technical hurdle for many organizations. This recent open-access study by McNeill et al. discusses approaches that were used in universities and schools across the country to assess ventilation needs and discusses best practices.

Featured Resource: All We Can Save

All We Can Save is an anthology of writings about the climate crisis by 60 women, centered on “Truth, Courage, and Solutions.” Edited by Dr. Ayana Elizabeth Johnson and Dr. Katherine K. Wilkinson, the anthology covers many aspects of climate action, activism, policy, history and more, from a viewpoint grounded in feminism. As a whole, the collection conveys a refreshing message of realism, compassion, cooperation, and hope.

The All We Can Save project, also co-founded by Dr. Johnson and Dr. Wilkinson, offers additional resources for educators, for building community, on working with climate emotions, and for workplace climate action.

We recently participated in a high school climate event organized in the spirit of All We Can Save. Students and faculty read the anthology and gathered for a day of discussion and activities. We joined alongside presentations from climate activists, artists, experts in building science, the fashion and food industries, climate medicine, and more. Our contribution was a presentation and demonstration on climate science basics, renewable energy, and climate engineering.

COVID-19 in India: Local Language Resources

In response to the current COVID-19 crisis in India, a group of scientists and public health experts has developed an infographic with tips and facts for managing the spread of SARS-CoV-2. The information has been translated into more than 20 local South Asian languages, as well as Spanish, French, and Portuguese. The Hindi version is below, and the rest of the languages can be found here.

The information on this infographic was also published in FAQ form by Indian online magazine, The Quint:

Respuestas a unas preguntas sobre la transmisión de COVID-19: por Prof. Jose-Luis Jiménez

El mundo de la investigación de COVID-19 se está moviendo muy rápidamente. Cada día hay más datos disponibles sobre las rutas de transmisión del virus y sus efectos. Ahora está claro que el virus es transmitado a través de aerosoles en el aire, y usar cubrebocas puede disminuir la propagación. El profesor Jose-Luis Jiménez (Twitter: @jljcolorado), de la Universidad de Colorado, ha escrito las respuestas a preguntas típicas para una entrevista en español / castellano. Prof. Jiménez hizo público el documento para difundir la información ampliamente. Se puede leerlo aquí: