PARIS, France, (AFP) – New research that links cooking with natural gas to around 12 per cent of childhood asthma cases has sparked debate about the health risks of kitchen stoves, as well as calls in the United States for stepped-up regulation.

The authors of the study said their findings suggested that around 650,000 US children would not have developed asthma if their homes had electric or induction stovetops, comparing the impact on health to that of second-hand smoke.

But an expert who was involved in the study questioned its findings and cautioned that gas remains far healthier than cooking with wood, charcoal and coal, which are estimated to cause 3.2 million deaths a year from household air pollution, overwhelmingly in developing countries.

The peer-reviewed US study was published last month 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 per cent of US childhood asthma cases to gas cooking.

The same calculation was previously used in 2018 research that attributed 12.3 per cent of childhood asthma cases in Australia to gas stoves.

A report released Monday used the same calculation to link 12 per cent of childhood asthma to gas cooking in the European Union.

The report, which has not been peer-reviewed, was released by the energy efficiency group CLASP and the European Public Health Alliance.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 Organization guidelines several times a week in all scenarios except for a large kitchen with a range hood that vented outside the home.

Nitrogen dioxide, which is emitted when gas is burned, is “a pollutant closely linked to asthma and other respiratory conditions,” according to the WHO.

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.

Richard Trumka Jr, a commissioner at the Consumer Product Safety Commission, tweeted on Monday that the agency “will consider all approaches to regulation”.

“To be clear, CPSC isn’t coming for anyone’s gas stoves. Regulations apply to new products,” he later added.

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 told AFP. “But it gives us a number that 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”.