A US study found that when people with poorly controlled asthma replaced gas or stovetops with electric stoves, hospitalizations and absences from work or school were reduced by 70%.
Ohio’s publicly-run MetroHealth began the study in December 2024, but funding was cut off early by the incoming Trump administration. The study aimed to find out whether replacing a gas cooker would improve asthma in 1,200 people living near Cleveland, Ohio.
“We completed the project with less than 100 households. As a result, more than 1,100 households did not receive any benefits, and we also had to lay off about 20 project staff,” said project leader Ashish Sehgal, a professor at Case Western Reserve University.
The team completed the ongoing stove replacement work and closed the project, but to the researchers’ surprise, the effects were clearly visible in a scaled-down study of 72 homes.
“We were surprised when we analyzed the results and found a very large effect size. Improvements in asthma symptoms after stove replacement were comparable to or greater than those reported in clinical trials of commonly used asthma medications,” Sehgal said.
Each person was assessed over a 4-week period before and after the gas cooker replacement, including scoring their asthma using an internationally recognized scale of 0 to 6.
The mean asthma score improved from 2.6 to 1.5. On this scale, a change of 0.5 is considered clinically significant. This includes fewer hospital visits and fewer days missed from school or work due to asthma flare-ups. They also found that they wheezed less, used their Liver inhaler less often, and were less likely to say their asthma woke them up in the middle of the night.
Air pollution was measured in 44 of these homes. Nitrogen dioxide was reduced by 70% on average.
Angela Brand, 38, of Akron, Ohio, said, “I didn’t realize gas stoves were a problem until I started using electric stoves. Now I need my inhaler much less often.”
Sehgal said, “The improvement in asthma control after replacing the stove was much greater than the improvement seen with the placebo drug, so a placebo effect is unlikely to explain our findings.” He added that it would be advantageous to repeat the study with more people and a control group.
Bradford-born NHS Dr Tiffany Yang, who was not involved in the US study, said: “The Ohio study adds to the evidence that reducing indoor air pollution can have meaningful health benefits, particularly for people with asthma. As governments and housing providers invest in improving their housing stock, indoor air quality should also be considered alongside energy efficiency and decarbonization measures to maximize health benefits.”
In an Ohio study, more than 97% of participants were satisfied or very satisfied with their new stove. A pilot stove and induction hob replacement project in Greater Manchester also achieved a high level of satisfaction.
More than a decade ago, an evidence review looked at 41 studies and concluded that gas cooking increases the risk of asthma in children. With gas cooking estimated to cause around 40,000 premature deaths each year across the EU and UK, improved health could be an important co-benefit of net-zero alternatives to gas cooking at home.
