The Tibet Autonomous Region in China is a unique place with high altitude and special Tibetan culture. The residents have different living habits and domestic fuels from those in other parts of China, however, knowledge on the emission characteristics of local residential fuels remain poorly understood until now. In this study, nine popular residential fuels in the Tibet are burned in situ to study the aerosol chemical compositions, mass spectral signatures, and emission characteristics from their burning emissions. Overall, emissions of particulate and gaseous pollutants depend strongly on the burning conditions, in addition to the fuel constituents themselves. Burning the biofuels of yak dung, WeiSang mixture fuels, and two powdery Tibetan incenses with relatively low combustion efficiencies can emit large amounts of CO and aerosols, especially organic aerosols (>90%) with large diameters. In contrast, burning of wood, coal, ghee lamp, stick-like Tibetan incense, and diesel can release abundant CO 2 but fewer aerosols from their flaming combustion. A comprehensive database consisting of the high-resolution mass spectra of organics and emission factors of multiple chemical components are established. Distinctly different mass spectral signatures are found among the different fuels, in particularly those unique Tibetan biofuels. All these findings have significant implications for the identification of aerosol sources, compilation of pollutant emission inventories, and assessment of potential environment effects in this remote region.

Fine particulate matter (PM 2.5 ) filter samples were collected from two high-altitude remote sites located in the southern (QOMS) and northern (WLG) regions of the Tibetan Plateau (TP) to explore the regional differences in brown carbon (BrC) properties. Chemical differences in BrC composition representative of these two areas were inferred from molecularlevel analysis of the PM 2.5 samples using high-performance liquid chromatography coupled with photodiode array and highresolution mass spectrometry detectors. The results show that more polar BrC chromophores were abundant in QOMS samples, while contributions from polar and less polar chromophores were comparable in WLG samples. A higher mass absorption coefficient of BrC was observed at QOMS than at WLG. Strong BrC chromophores in QOMS samples were identified as oxygenated aromatics and nitrophenol compounds, while organosulfate compounds were found in the WLG sample. The results of this study indicate regional differences in BrC chromophores and provide insights into their sources and chemical processes, which should be considered for predictive understanding and modeling of the radiative forcing of aerosol in the TP area.