A recent US study has found that replacing gas stoves and hobs with electric alternatives can lead to a substantial 70% reduction in hospital admissions and days missed from work or school for individuals suffering from poorly controlled asthma. The findings, from a team in Ohio, indicate that the health improvements are comparable to, or even greater than, those achieved with commonly used asthma medications.
The study, initiated by Ohio’s publicly owned MetroHealth in December 2024, was originally designed to assess the impact of gas cooking replacement on asthma for 1,200 people near Cleveland. However, funding for the project was prematurely terminated by the incoming Trump administration, forcing the study to be scaled back significantly.
Prof Ash Sehgal of Case Western Reserve University, who led the project, expressed disappointment over the early termination. “We had completed the project at fewer than 100 households. As a result, over 1,100 households were unable to benefit. We also had to lay off about 20 project staff,” Sehgal stated.
Despite the drastic reduction in scope, with benefits clearly detected in a scaled-down study of 72 homes, researchers were surprised by the magnitude of the positive outcomes. “We were surprised when we analysed the results and found a very large effect size,” Sehgal noted, highlighting that the improvements in asthma symptoms were on par with or exceeded those seen in clinical trials for many asthma drugs.
Participants were evaluated for four weeks before and four weeks after the gas cooking replacement, using an internationally recognized asthma scale from zero to six. The average asthma score improved from 2.6 to 1.5, a change considered clinically significant given that a 0.5 point shift is deemed meaningful. This improvement included fewer hospital visits and fewer days off for asthma flare-ups, as well as reduced wheezing, less reliance on reliver inhalers, and fewer reports of asthma waking individuals during the night.
Measurements of air pollution in 44 of the homes revealed an average 70% drop in nitrogen dioxide levels after the switch to electric cooking.
Angela Bland, a 38-year-old resident of Akron, Ohio, shared her personal experience: “I didn’t realise my gas stove was the issue until I used the electric stove. I now need my inhaler way less often.”
Prof Sehgal also addressed the possibility of a placebo effect, stating, “The improvement in asthma control after changing stoves was much larger than improvements seen with placebo drugs, so the placebo effect is unlikely to explain our findings.” He suggested that repeating the study with a larger participant group and a control group would be beneficial.
Dr Tiffany Yang from NHS Born in Bradford, who was not involved in the US research, commented on the broader implications. “The Ohio study adds to the growing evidence that reducing indoor air pollution can have meaningful health benefits, particularly for people with asthma,” she said. Dr Yang emphasized that indoor air quality should be a key consideration alongside energy efficiency and decarbonisation when governments and housing providers invest in improving housing stock, to maximize health benefits.
Participant satisfaction was notably high, with over 97% of those in the Ohio study reporting they were satisfied or very satisfied with their new electric stove. Similar high levels of satisfaction have also been observed in a pilot stove and induction-hob replacement project in Greater Manchester.
The findings align with an evidence review conducted more than 10 years ago, which analyzed 41 studies and concluded that gas cooking increased the risk of asthma in children. With an estimated 40,000 early deaths each year attributed to gas cooking across the EU and UK, improved health outcomes represent a significant co-benefit of net-zero initiatives aimed at replacing gas cooking in homes.
