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An intensive field experiment was conducted at an urban and a rural site in Hong Kong to identify the influence of biomass burning emissions transported from distinct regions on ambient aerosol in coastal southeast China. Water-soluble ionic and carbonaceous species, specifically the biomass burning tracer levoglucosan, were analysed. Elevated levoglucosan concentrations with maxima of 91.5 and 133.7 ng m and overall average concentrations of 30 and 36 ng m were observed at the rural and urban sites, respectively. By combining the analysed meteorological data, backward trajectories, fire counts and Aerosol Index from the Earth Probe satellite, southwest China and the northern Philippines, together with the southeast China coast, were identified for the first time as source regions of the transported biomass burning particles at the surface level in rural Hong Kong. Occasional levoglucosan enhancements observed at urban Hong Kong were attributed to local incense and joss paper burning during the Ching-Ming festival period. The contributions of transported biomass burning emissions, especially from the northern Philippines, were estimated to account for 7.5% and 2.9% of OC and PM, respectively. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau is one of the highest regions in the world, exerting profound influence on the large-scale atmospheric circulation of Asia and the global climate. Here we report ambient concentrations of black carbon (BC), aerosol mass (PM and PM) and associated carbonaceous species and water-soluble inorganic ions from a remote mountain site in the southeastern part of the Tibetan Plateau during spring, in order to characterize the major sources contributing to the ambient aerosol in the background atmosphere of Southeast Asia. Significant build-up of aerosol and BC concentrations was observed during a dry period, accompanied by the occurrence of fires and transport of pollution from the nearby regions of Southeast Asia and the northern part of the Indian Peninsula. The concentrations of BC, PM and PM mass reached maximum hourly values of 1470 ng m, 107 and 117 μg m, respectively. Organic carbon (OC), elemental carbon (EC) and sulfate were the predominant aerosol components. OC showed strong correlations with EC ( R= 0.93 for PM and 0.74 for PM) and non-sea-salt potassium, especially in fine aerosol ( R= 0.95). In addition, the relative change rates of K against OC reached characteristically high values, highlighting the important contributions of biomass-burning smoke. [ABSTRACT FROM AUTHOR]