Insights into immune and oxidative stress in rural homemakers exposed to VOCs during typical solid fuel utilization activities

Exposure to volatile organic compounds (VOCs) emitted from solid fuel combustion can pose significant health risks, but the mechanism by which VOCs exposure affects health remains vague. This study explored the impacts of personal exposure (PE) to VOCs during three typical household solid fuel utilization scenarios (heating, cooking, and background) on inflammatory, oxidative stress, and hematological indices. Personal VOC samples from the three scenarios were collected using Tenax-TA adsorbent tubes with a portable device, and blood and urine samples were obtained from the subjects for biomarker analysis. The median total quantified VOCs concentration from cooking (671.8 ppbv) was 2.3 times higher than from heating and 10.5 times higher from background. The diverse fuel-use scenarios triggered unique pathogenic pathways in biochemical responses. Notably, cooking was associated with increases in measured serum biomarkers (glutathione peroxidase (GSH-Px), Clara cell secretory protein (CC16)), whereas heating produced greater adverse impacts on hematotoxicity than did cooking. The defensive and protective responses against oxidative stress induced by vinyl chloride (Spearman correlation coefficient, denoted as R = −0.629) and inflammation and oxidative stress induced by 1,4-dioxane (R = 0.536–0.564) were observed during cooking. Personal exposure to several non-carcinogenic VOCs (n-hexane, toluene, ethylbenzene, etc.) resulted in monocyte count reduction during cooking and heating (R = −0.872–0.542). Conclusively, indoor solid fuel combustion significantly induced human immune response and inflammation regulation. The findings provide insights into the health impact mechanism of VOCs from indoor fuel combustion and references for establishing precise strategies for various solid fuel usage scenarios.