Understand the connection between gas stoves and asthma

If you are an asthma or allergy patient, chances are you have been avoiding using a gas stove. After all, reports have suggested that cooking on these stoves could be triggering your allergies and leaving you with uncomfortable—and possibly dangerous—symptoms like coughing, sneezing, or headaches. However, before deciding to avoid using a gas stove altogether, it is important to understand the actual facts about how this type of kitchen appliance can affect those with breathing conditions such as asthma and allergies. In this blog post we will take an in-depth look at the potential benefits and dangers of cooking with a gas stove for people who suffer from respiratory problems so that you can make more informed decisions when it comes to your health.

Gruenwald T, Seals BA, Knibbs LD, Hosgood HD 3rd. Population Attributable Fraction of Gas Stoves and Childhood Asthma in the United States. Int J Environ Res Public Health. 2022 Dec 21;20(1):75. doi: 10.3390/ijerph20010075. PMID: 36612391; PMCID: PMC9819315.

Indoor gas stove use for cooking is associated with an increased risk of current asthma among children and is prevalent in 35% of households in the United States (US). The population-level implications of gas cooking are largely unrecognized. We quantified the population attributable fraction (PAF) for gas stove use and current childhood asthma in the US. Effect sizes previously reported by meta-analyses for current asthma (Odds Ratio = 1.34, 95% Confidence Interval (CI) = 1.12−1.57) were utilized in the PAF estimations. The proportion of children (<18 years old) exposed to gas stoves was obtained from the American Housing Survey for the US, and states with available data (n = 9). We found that 12.7% (95% CI = 6.3−19.3%) of current childhood asthma in the US is attributable to gas stove use. The proportion of childhood asthma that could be theoretically prevented if gas stove use was not present (e.g., state-specific PAFs) varied by state (Illinois = 21.1%; California = 20.1%; New York = 18.8%; Massachusetts = 15.4%; Pennsylvania = 13.5%). Our results quantify the US public health burden attributed to gas stove use and childhood asthma. Further research is needed to quantify the burden experienced at the county levels, as well as the impacts of implementing mitigation strategies through intervention studies.

So, 12.7% of of childhood asthma can be prevented if gas stove use was not present? Wait a minute, not so fast! Many strategies can be implemented to reduce or eliminate asthma that has nothing to do with gas cooking:

  • Follow your doctor’s instructions to use a controller medication for asthma. This simply means if you are prescribed an inhaled corticosteroid, use it to PREVENT exacerbations of asthma before they happen, not just when you get into trouble.
  • Be mindful of your asthma triggers. Asthma is a condition of respiratory inflammation that can be triggered by infection, allergies, exercise, irritants just to name a few. If you already have asthma, it’s probably not a good idea to increase your exposure to gas stoves, but be mindful of ALL of your asthma triggers.
  • Have a rescue plan for when you do get into asthma problems, such as steroids on hand, bronchodilators to use every 3-4 hours to abort an attack before it becomes a problem.

CookingwithNaturalGas: JusttheFacts, Please JohnR.Balmes1,2,3,StephanieM.Holm1,2,3,MeredithC.McCormack4,5,NadiaN.Hansel4,5,LynnB.Gerald6,7, andJerryA.Krishnan6,7 (American Journal of Respiratory and Critical Care Medicine Volume 207 Number 8 | April 15 2023)

A media firestorm about the impacts of gas cooking on indoor air quality was ignited after comments by a member of the Consumer Product Safety Commission (CPSC) about a potential national ban on new gas stoves (1). The CPSC later clarified that such a ban is not coming in the immediate future. We are writing to share the key facts on gas cooking and its relationship to climate change and adverse health effects. Do Gas Stoves Contribute to Climate Change? Natural gas is the primary residential fuel type for heating and cooking in the United States, with 15% of all natural gas use attributed to residential consumers (2). Methane, the primary constituent of natural gas, is a potent greenhouse gas that is 86 times more potent than CO2 (3). As a result, government policies have been directed at reducing methane emissions, including banning natural gas hookups in new residential construction in some municipal jurisdictions. Recently, government officials have also focused attention on the potential health co benefits of eliminating natural gas cooking as a source of indoor air pollution. What Are the Adverse Health Effects of Gas Stoves? Cooking-related emissions vary with the type of energy used. Some pollutants, such as fine particulate matter with an aerodynamic diameter <2.5 μm (PM2.5), are released during cooking, regardless of fuel type. The primary pollutant of health concern emitted uniquely by gas (and not electric) cooking is nitrogen dioxide (NO2), but products of incomplete natural gas combustion include polycyclic aromatic hydrocarbons, formaldehyde, carbon monoxide, and ultrafine particles (4). Nitrogen oxides are irritant gases that can cause bronchoconstriction, airway hyperresponsiveness, and airway inflammation with increased risk of asthma exacerbations, bronchitis, and wheezing (2). Outdoor NO2 is regulated by the U.S. Environmental Protection Agency with a 1-hour National Ambient Air Quality Standard (NAAQS) of 100 ppb, primarily because of epidemiologic studies that have demonstrated associations between exposure and worsening of asthma in children and adults as well as controlled human exposure studies that have demonstrated increases in airway responsiveness in adults with asthma (5). Peak indoor NO2 concentrations generated by gas cooking often exceed this healthbased NAAQS that has been set for outdoor air quality (2). This is especially true for kitchens with poor ventilation or where range hoods are not used or working properly. Even at levels below the current NAAQS, NO2 exposures may impact allergic asthma through enhancement of the airway responses to specific aeroallergens, though this is less well described (5). A 2013 systematic review and meta-analysis of gas cooking and current asthma (n= 10 studies in North America and Europe) reported a pooled odds ratio of 1.34 with a 95% confidence interval of 1.12–1.57 (6). A recent publication used this effect to estimate that 13% of childhood asthma could be prevented by eliminating gas cooking (7), but that does not mean that eliminating gas cooking is the only way to prevent those asthma cases. That article helped spur the CPSC and media to focus on the potential health hazards. Although the observational epidemiology studies used for that effect estimate suggest a strong association between gas cooking and asthma, this topic would benefit from a randomized controlled trial (RCT) to minimize confounding and support causal inferences.

So what can we learn from this study:

  1. RCT or randomized, controlled clinical trials are the gold standard to effective medical research. Remember that the best research comes when investigators and doctors realize the need for RCT design to determine cause & effect, not just survey results. Two of the authors (J.R.B. and S.R.H.) have secured California Energy Commission funding to conduct such a study. Kudos to your group. I look forward to results.
  2. How Can Exposure to Cooking-related Pollutants Be Reduced?
    By far, the most important question is what can we do about gas cooking? An RCT coauthored by two of us (M.C.M. and N.N.H.) demonstrated
    that electrification of cooking can decrease NO2 levels in the kitchen
    and bedroom. This key RCT also showed that air filtration devices
    can reduce NO2 levels, and there is additional evidence that the use of
    stove range hoods can reduce concentrations of both NO2 and PM2.5. All good findings to encourage good environmental control. But which type do I use?
  3. The use of a high-efficiency particulate absolute air filtration device (HEPA) will primarily reduce PM2.5; the inclusion of an activated charcoal filter can effectively reduce NO2. And here in lies the problem with bad ventilation: for the asthmatic patient, we need to reduce both PM 2.5 and nitrogen dioxide. Because emissions of PM2.5 occur with both electric and gas cooking, the regular use of a properly working
    and vented stove range hood is recommended for all cooking (using
    either kind of fuel), especially when frying foods at high temperature.
  4. What Are Evidence-based Recommendations
    for Clinicians?
    Both the latest National Asthma Education and Prevention Program guidelines and the Global Initiative for Asthma strategy report call for
    people with asthma to avoid exposure to respiratory tract irritants
    because of the potential for exacerbations. As noted above,
    NO2 is a respiratory tract irritant at concentrations that may occur in
    some homes during gas cooking. If you already have asthma, why risk cooking with a gas stove when the NO2 may exacerbate your asthma?
  5. Given the potential health co benefits of electrification of
    cooking, households that include individuals with asthma, chronic
    obstructive pulmonary disease, or other respiratory diseases should
    make the transition if feasible, and all households could consider
  6. All households should use good ventilation while cooking to
    reduce PM2.5 concentrations (e.g., a stove range hood vented to
    the outside) and/or a portable high-efficiency particulate air
    filtration device that includes an activated charcoal filter. (this gets rid of NO2)
  7. We hope that decreasing exposure to cooking emissions will improve
    the health of people with respiratory disease. Decreasing
    production of those emissions in the first place could also
    benefit the planet.

Tips for Improving Air Quality at Home – Learn how to make your home an asthma-friendly environment

As we spend more time indoors, it is becoming increasingly important to create a comfortable and safe living environment, especially for those with asthma. One potential irritant that many people may overlook is gas stove emissions. Gas stoves can release pollutants such as nitrogen dioxide, which irritates the lungs and can trigger asthma symptoms. Fortunately, there are steps you can take to make your home an asthma-friendly environment. For example, consider switching to an electric stove or installing a vent hood to help reduce gas emissions, particularly the use of activated charcoal to decrease NO2. By making small changes like these, you can help improve the air quality in your home and reduce the risk of an asthma attack.

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