A study linking cooking with natural gas to about 12% of childhood asthma cases has ignited debate about the health risks of kitchen stoves, while the WHO says nitrogen dioxide, emitted when gas is burned, is “a pollutant closely linked to asthma and other respiratory conditions”.
The authors of the US study said their findings suggested that around 650 000 children would not have developed asthma if their homes had electric or induction stove-tops, comparing the impact on health to that of second-hand smoke.
But one expert who was involved in the study questioned its findings, saying gas was far healthier than cooking with wood, charcoal and coal, which are estimated to cause 3.2m deaths a year from household air pollution, overwhelmingly in developing countries.
The Citizen reports that the peer-reviewed US study was published in the International Journal of Environmental Research and Public Health.
It is based on a calculation of the risk of developing asthma in homes with a gas stove from a 2013 review of 41 previous studies. Combining that calculation with US census data, it linked 12.7% of US childhood asthma cases to gas cooking.
The same calculation was previously used in 2018 research that attributed 12.3% of childhood asthma cases in Australia to gas stoves.
Another recent report used the same calculation to link 12% of childhood asthma to gas cooking in the European Union, and was released by the energy efficiency group CLASP and the European Public Health Alliance.
N02 levels exceed limits
The European report included computer simulations conducted by the Netherlands’ research organisation TNO analysing exposure to air pollution in different European household kitchens.
The level of nitrogen dioxide was found to exceed EU and World Health Organisation guidelines several times a week in all scenarios except for a large kitchen with a range hood that vented outside the home.
This year, CLASP will collect air quality measurements from 280 kitchens across Europe in a bid to confirm the results.
The research comes amid heightened scrutiny of gas stoves in the United States.
The American Gas Association, a lobby group, denounced the US study as an “advocacy-based mathematical exercise that doesn’t add any new science”.
Brady Seals, a manager at the Rocky Mountain Institute and co-author of the study, rebuffed the lobby group’s statement.
“Of course it’s just math,” she said. “But it gives us a number we never had before.”
‘Not clean’
Rob Jackson of Stanford University, who has previously published research showing that climate-warming methane can leak from gas stoves even when they are switched off, said the US paper was “supported by dozens of other studies concluding that breathing indoor pollution from gas can trigger asthma”.
But researchers working to transition the 3bn people still cooking with harmful solid fuels like wood, coal and charcoal to cleaner sources expressed concern.
Daniel Pope, a professor of global public health at the UK’s University of Liverpool, said the link between asthma and pollution from gas stoves had yet to be definitively proven and further research was needed.
Pope is part of a team conducting research commissioned by the WHO to summarise the effects different kinds of fuel for cooking and heating can have on health.
The results, which will be published later this year, indicate a “substantial reduction in risk” when people switched to gas from solid fuels.
Study details
Population Attributable Fraction of Gas Stoves and Childhood Asthma in the United States
Talor Gruenwald, Brady Seals, Luke Knibbs, Dean Hosgood.
Published in the International Journal of Environmental Research and Public Health on 21 December 2022
Abstract
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.
Gas-Report
International Journal of Environmental Research and Public Health article – Population Attributable Fraction of Gas Stoves and Childhood Asthma in the US (Open access)
The Citizen article – Asthma study sparks debate about safety of cooking with gas (Open access)
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