The debate is heating up over whether indoor nitrogen dioxide (NO2) emissions from gas and propane stoves has risen to a dangerous level, contributing to asthma and chronic obstructive pulmonary disease (COPD). New research has provided quantified data on that debate.
In a recent study published in Science Advances, scientists looked at the health impact of the emissions as well as the demographic disparities of such exposure. Gas and propane stoves are used in more than 50 million U.S. homes and millions more around the globe. They emit pollutants like NO2 and benzene (C6H6), which are known pulmonary irritants linked to asthma and COPD.
The research confirmed that total gas or propane burned was the most critical factor in predicting NO2 exposure levels, followed by ventilation practices and time spent in the kitchen. Additionally, the study concluded that long-term and short-term NO2 exposure was much higher in smaller and low-income homes. Racial and ethnic disparities were highest among Indigenous, Latino and Black households exposed to NO2 versus white and Asian households. Researchers also looked at behavioral factors, including the duration and intensity of stove use. Among study participants, residences with high stove use saw significantly higher NO2 exposure over both the short and long term.
This study provided more detail than previous studies, which lacked precision in assessing exposure due to variations in stove usage and ventilation. The recent study defined various terms to standardize the terminology. For example, a flat surface featuring two to six cooking elements was defined as a cooktop, while a stove with “burners” was characterized by its use of a gas or propane flame. Researchers also looked at elements, such as open windows and doors, outside-venting range hoods and recirculating range hoods which filter and return polluted air back into the kitchen.
Finally, researchers used the CONtaminant Transport Analysis Model (CONTAM) multizone indoor air quality model, developed by the National Institute of Standards and Technology (NIST), to measure indoor NO2 concentrations. The research team calculated emission rates within private and rented spaces in large metropolitan areas, including the San Francisco Bay Area, Los Angeles, Denver, Houston, New York City and Washington, DC. The CONTAM model estimated NO2 exposure across a mix of environmental, behavioral and demographic conditions. Scientists also used epidemiological data to study health impacts, paying special attention to pediatric asthma.
