UNSW Sydney experts explain why cooking with gas contributes to poor Indoor Air Quality (IAQ) and causes asthma.
The last few years have seen mounting evidence that cooking on a gas stove is bad for our health and sourcing the gas is damaging for the environment.
While the concern over their safety is not exactly new, a recent study re-sparked the debate as research estimated that a significant proportion of childhood asthma cases in the United States is attributable to the exposure to emissions released from gas stoves.
The conversation culminated at the beginning of this year when the Consumer Product Safety Commission announced it would consider banning the use of gas stoves in the United States.
But putting US culture wars aside, what does the science say about the impact of cooking with gas?
Associate Professor Donna Green, chief investigator of the Digital Grid Futures Institute at UNSW Sydney, said cooking with gas means households are getting a regular does of air pollutants close to the face.
Gas stoves are turned on when gas flows through the supply pipe to the burner, where an electronic ignition system creates a spark to form the blue flame.
“When you're burning gas, you're largely burning methane. And the problem with that is that you create toxic compounds as a result,” Green said.
Burning methane, a primary component of gas, creates heat, which can enable nitrogen and oxygen to form nitrogen dioxide (NO2).
“NO2 is a problem because it can cause a range of very serious health problems, including asthma,” Green said.
But it doesn’t end there. "When the stove is lit, you’re burning a fossil fuel, and in the process, it can also emit carbon monoxide, nitrous oxides and formaldehyde.”
Carbon monoxide is another chemical with potentially dangerous repercussions on health.
“Carbon monoxide is emitted when gas is burnt and will deplete the oxygen in the air, and deplete oxygen in the blood too,” according to Dr Christine Cowie, an environmental epidemiologist at UNSW Medicine & Health.
Poisoning from elevated levels of carbon monoxide can cause headaches and dizziness.
“But people can also become unconscious from carbon monoxide poisoning, and in extreme cases it can lead to death,” she said.
There have also been studies which have shown gas stoves release other harmful components, including benzene, a cancer-causing agent.
“We have known there is an association between NO2 and asthma in that it can exacerbate symptoms in people with respiratory disease such as asthma and chronic obstructive pulmonary disease (COPD),” Dr Cowie said.
“Exposure to nitrogen dioxide in ambient air has been linked to an increased risk of asthma and other respiratory symptoms, but more recently there is increasing evidence to suggest that NO2 is likely to be a direct cause of asthma in children,” she said.
With an estimated one in 10 Australian children affected by asthma, these latest results are cause for concern. Then there are the climate concerns.
Methane is a very potent greenhouse gas, producing carbon dioxide, and that's heating the planet and causing a global climate emergency.
The main alternative to gas cooking is electrical stoves, which includes induction stoves. Induction stoves work by generating heat electromagnetically and are the most energy efficient method of generating heat for cooking.
