A warning has been issued to anyone with a gas hob in their kitchen after it emerged that more pollution comes from a gas hob than from one of Britain’s busiest roads. Which? carried out a snapshot investigation into how everyday cooking activities affected levels of nitrogen dioxide (NO2) and fine particulate matter (PM2.5) inside the average home.
It gave air quality monitors to five volunteers – four with gas hobs and one with an induction hob – in order to find out how everyday cooking activities affected levels of pollution inside the average home. The study, conducted in November 2024, found that NO2 levels from a gas hob increased in line with the amount of cooking time and the number of gas rings used. Even when slow-cooking a meal using one ring, NO2 levels more than doubled – in one case, pushing past 60 micrograms per cubic metre. The WHO recommended limit for NO2 is 10 micrograms per cubic meter.
Three of the volunteers using a gas hob experienced PM2.5 peaks of more than 100 micrograms per cubic metre on several occasions, and one volunteer experienced a peak PM2.5 of nearly 650 micrograms per cubic metre. The WHO recommended limit for PM2.5 is 15 micrograms per cubic metre.
Elevated levels of both continued for several hours after cooking, showing that pollution spreads rapidly through the home. NO2 experienced by the volunteer in Which?’s study who used the induction hob was mainly from outdoor pollution.
Over the same period, average hourly NO2 levels on London’s busy Marylebone Road reached 33 micrograms per cubic metre.
The latest Climate Change Committee report highlighted the dangers posed by gas ovens and hobs, focusing on the harmful pollutants they release. NO2 and PM2.5 are known to be some of the most damaging both indoors and outdoors, with long-term exposure contributing to serious health risks.
Gas cookers have also been linked to respiratory issues, including asthma, coughing, and wheezing. A study published in The International Journal of Epidemiology revealed that children living in homes with gas stoves were 42% more likely to develop asthma.
PM2.5 has been linked to the worsening or development of several diseases, including respiratory illnesses, lung cancer, an increased risk of heart disease and Parkinson’s disease.
Which? also found awareness of indoor air pollution is low. In a survey about air pollution, only 25% of those with gas hobs and 20% with electric hobs said they were worried about the impact it could have on their health.
However, a third of the people were concerned about outdoor air pollution coming in through open windows.
Which? energy and sustainability editor Emily Seymour said: “It’s shocking to think that something as routine as cooking dinner could be releasing harmful pollutants into our own homes.
“But our snapshot research shows that once it spikes, air pollution can spread rapidly through the house and linger for long periods of time.
“We still don’t know the full impact of indoor pollutants on our health but if it is something you are concerned about, ventilating by using your extractor hood and opening windows can make a big difference.
“If you are using a gas hob you could consider switching to induction when you next need to replace your hob.”