Impact of China’s Clean Heating Policy on Biomarkers of Inflammation and Oxidative Stress in Rural Beijing Adults: A Difference-in-Differences Analysis

Household air pollution from coal and biomass combustion can increase chronic inflammation and oxidative stress, two biological pathways central to noncommunicable disease (NCD) development. In 2015, Beijing implemented a clean heating policy (CHP), replacing household coal stoves with gas or electric heating devices in rural areas. Leveraging the phased village-level rollout of the CHP as a natural experiment, we estimated its effects on blood biomarkers of inflammation and oxidative stress (IL-6, TNF-α, CRP, and MDA) using a difference-in-differences (DiD) approach. We analyzed data from 1064 adults residing in 50 rural villages across two winter seasons (2018–2019, 2019–2020). Among the 50 villages, 10 were treated by the CHP between the first and second winter. Sociodemographic data were collected during home visits, and venous blood samples were obtained at village clinics. Biomarkers were measured using ELISA (IL-6, TNF-α, CRP) and HPLC (MDA). We applied generalized linear models with a Gamma distribution and log link, clustering standard errors at the village level. Missing covariate data were addressed via multiple imputation. We found no consistent evidence that the CHP affected the average levels of IL-6, TNF-α, CRP, or MDA in treated villages. Sex-stratified analyses suggested possible heterogeneity, although findings were not consistent across biomarkers. These results indicate that the short-term effects of the CHP on systemic inflammation and oxidative stress were inconclusive overall.