Environmental impacts of polarity-resolved water-soluble organic matter from animal dung burning on the Qinghai-Tibet Plateau

Abstract. Animal dung was widely used for rural heating and cooking on the Qinghai-Tibet Plateau (QTP), its contributions to climate-relevant and health-related aerosol properties remain poorly understood. In this study, water-soluble organic matter (WSOM), which separated into neutral humic-like substances (HULIS-n), acidic humic-like substances (HULIS-a), and highly polar WSOM (HP-WSOM), in PM_2.5 from yak and sheep dung on the QTP were conducted to evaluate their radiative forcing and oxidative potential (OP). It showed that HULIS-a and HULIS-n exhibited the highest emission factors under heating (0.80±0.46 g/kg) and cooking (0.35±0.36 g/kg) scenarios, respectively. HULIS-n exhibited the strongest light absorption compared to the highest OP for HP-WSOM. Total WSOM-C emissions from animal dung combustion on the QTP were 7.5 Gg and 2.0 Gg for heating and non-heating season, with sheep dung for heating contributing the largest (40.6 %). Spatial distributions of radiative forcing and OP were highly correlated with the intensity of sheep dung. The estimated radiative forcing of WSOM corresponded to 10.9–34.7 % of black carbon, suggesting that WSOM may be an important contributor to regional atmospheric warming and cryosphere change on the QTP. Scenario analysis showed that replacing 50 % of sheep dung combustion with yak dung could reduce regional radiative forcing and OP by 2.4×10⁴ MW/km² and 948.8 (AU s^-1g^-1)/km². These findings highlight the importance of animal dung combustion to light-absorbing and redox-active organic aerosols on the QTP and provide scientific support for cleaner household energy strategies and fuel-use optimization in the region.