Abstract Residential solid fuel combustion is a significant source of products of incomplete combustion (PICs), raising concerns about air pollution and public health. While fuel and stove effects on PIC emission are well‐studied, the role of oxygen levels at different altitudes is less understood. This study quantitatively evaluated the influence of oxygen levels (18.2%–26.6%) on emission factors (EFs) of fine particulate matter (PM 2.5 ), organic carbon (OC), elemental carbon (EC), carbon monoxide (CO), nitrogen oxides (NO x ), and sulfur dioxide (SO 2 ), as well as on the oxidative potential (OP) of PM 2.5 from residential biomass combustion. The PIC emissions were significantly influenced by oxygen levels, with EFs of PM 2.5 , OC, EC, and CO at 18.2% oxygen levels being 6.9–49 g/kg, 0.39–5.7 g/kg, 0.050–0.76 g/kg, and 65.9–244 g/kg, respectively, significantly higher than those at 20.4%–26.6%, by up to 90%, consistent with reduced combustion efficiency under oxygen‐deficient conditions. Notably, oxygen‐enriched combustion (>24.4%) may increase PM 2.5 , EC, SO 2 , and particularly NO x emissions, likely due to enhanced combustion temperature. The effect of oxygen levels on OP is fuel‐dependent, with no consistent trend observed across different biomass types. Additionally, differences in PIC emissions among fuels were amplified at oxygen‐deficient combustion due to varying sensitivity, emphasizing the need to consider fuel‐specific responses in mitigation strategies, particularly in high‐altitude regions. The ratio of char‐EC/soot‐EC remained consistent across oxygen levels, serving as a more reliable indicator in source apportionment than the OC/EC ratios. These findings offer valuable insights for designing altitude‐specific emission control strategies and improving the understanding of oxygen effects on PIC emissions.
Du et al. (Thu,) studied this question.