Australia’s federal government looks like it’s digging its heels in on gas but be warned, cooking with it is bad for your health. And while rangehoods can help, not all of them were created equal. In fact, the best ones are so loud people don’t turn them on.
Australia is on course for a gas-fired economic recovery, with renewed talk of putting in a $6 billion gas pipeline from one end of the country to the other. The fossil fuel’s credentials as a “transition fuel” have been contested loudly but there’s another downside to gas that gets far less airtime – cooking with the stuff is bad for your health, especially children.
Gas might be favoured by top chefs but there’s an overwhelming body of evidence that’s been gathered in the past 20 years to suggest that it puts our respiratory health at risk – something that’s pretty top of mind at the moment.
In fact, a recent study on the health effects of cooking with gas out of California opened with a reminder that air pollution and susceptibility to COVID-9 are linked.
“New evidence suggests that a small increase in long-term exposure to fine particulate matter (PM2.5) leads to a large increase in the COVID-19 death rate; this further establishes the substantial value in protecting the population from the respiratory vulnerability caused by widespread air pollution,” the study by UCLA Fielding School of Public Health stated.
The impact of gas on air quality has received scant attention considering how many people cook with gas around the world, with around 38 per cent of Australian homes fitted out with a gas cooking appliance.
A 2018 study led by University of Queensland researcher Luke Knibbs found that around 12 per cent of childhood asthma around the country can be contributed to gas cooking.
While this might not sound like many, as the researchers point out: “the proportion of the population exposed is relatively large, so that the contribution to the population asthma burden is considerable.” (Note that the study also included the contribution of household mould to childhood asthma).
In the US, the situation looks worse. A comprehensive literature review of two decades worth of research on this topic by the Rocky Mountain Institute, Mothers Out Front, Physicians for Social Responsibility, and the Sierra Club shows that living in a home with a gas cooking increases the risk of a child having asthma by 42 per cent.
How bad can it really be?
Childhood asthma is not the only adverse health effect we need to worry about.
Formaldehyde, carbon monoxide and nitrogen dioxide (NO2) are among a nasty cocktail of offending particles and gases emitted by gas cooktops that can cause adverse health effects. Homes with gas stoves found to have NO2 concentrations 50 – 400 per cent higher than homes with electric stoves.
According to research from organisations such as the Rocky Mountain Institute, exposure to NO2 only a little higher than outdoor concentrations can exacerbate symptoms of asthma in adults.
Beyond asthma, gas cooktops are linked to other respiratory conditions – everything from an uncomfortable wheeze to something more serious such as chronic obstructive pulmonary disease.
Elevated NO2 levels have also been linked to other conditions such as cardiovascular problems, diabetes, cancer, reproductive issues and brain development in children.
Extraction devices can help but relying on them is dangerous
Rangehoods that extract the problem particles out of the air can be effective, but these devices vary in quality and subsequent effectiveness. The best on the market vent the polluted air outdoors and can capture particles and gases with greater than 75 per cent efficiency.
From there, there’s a steep decline to lower performance devices with less extraction power or devices that simply recirculate air. At this lower end of the spectrum, as little as 15 per cent of pollutants are captured.
Good rangehoods work. According to Dr Knibbs from UQ, high-efficiency range-hoods could reduce the amount of childhood asthma associated with gas stoves from 12 per cent to just three per cent.
While a powerful rangehood that vents outside can be enough to offset most of the harmful effects of gas cooktops, these are typically super noisy.
As a result, people with the top-of-the-range ventilation equipment are likely to be among the significant cohort who don’t habitually turn them on. A survey of Melburnians found that 44 per cent of people in the city did not use them regularly.
It’s also unclear how many homes in Australia are kitted out with rangehoods that are effective, and regulation in this space appears patchy. According to Building Connection, the National Construction Code does not explicitly mention rangehood ducting or the ventilation of kitchens in the air quality section. There are some requirements, thankfully, for those living in combined living/sleeping area and large commercial kitchens (The Fifth Estate welcomes further information on this – firstname.lastname@example.org).
While proper ventilation indeed helps, RMI research concluded that “we cannot rely on current exhaust ventilation practices alone to protect families from unsafe levels of gas stove pollution”.
In addition, energy efficiency upgrades to stop air escaping and seal the build envelope can inadvertently exacerbate the impacts of gas stovetops.
What can be done
The RMI report proposes a series of recommendations to improve what it describes as a “significant and solvable health problem in plain view” in the US, with the switch to electric cooktops the ideal long-term solution.
“The health case for transitioning to all-electric cooking has been slowly mounting for more than 40 years but policymakers must urgently address air pollution now,” said Brady Seals, senior associate at Rocky Mountain Institute and report author.
Other suggestions are directed at regulation, such as rules forcing manufactures to produce appliances that are safe.
If you’re an individual worried about health effects but can’t afford to switch to an electric cooktop, there are ways to mitigate the problem.
Always open the windows and turn on the exhaust hood during cooking. Other options are installing a low-level carbon monoxide detector, or using a plug-in induction cooktop.