Exploring the Relative Effects of Natural Gas and Biogas Cooking on Indoor Air Quality in Residential Kitchens

Indoor air pollution from gas stove combustion remains a public health concern, given links to adverse cardiorespiratory health effects, yet few studies have characterized or compared the air quality impacts of different gas-based cooking fuels. We investigated kitchen-level concentrations of nitrogen dioxide (NO2) and fine particulate matter (PM2.5) concentrations in four homes in Central Pennsylvania that used natural gas and/or biogas fueled stoves. We conducted time-resolved kitchen monitoring and assessed pollutant concentrations during cooking and non-cooking periods. We applied linear mixed-effect regression models with kitchen-level random effects and time-varying covariates to estimate the influence of fuel type on indoor air quality. During cooking, mean kitchen NO2 concentrations during cooking were more than 160% higher in homes using natural gas compared with biogas (95% confidence interval [CI]: 109.4%, 211.1%), although both levels remained below the WHO guideline. PM2.5 concentrations showed limited sensitivity to fuel type, with modest differences observed. Adjusted mixed-effect regression models revealed attenuated but consistent associations, with natural gas use increasing NO2 exposure by 2.8 ppb, or 60.3% (95% CI: 1.7, 4.6 ppb). These findings suggest further research into understanding the exposure and health benefits of alternative fuels in residential kitchen settings is merited.