Airborne particulate organics at the summit (2060m, a.s.l.) of Mt. Hua in central China during winter: Implications for biofuel and coal combustion

Sugars, n-alkanes and PAHs in PM ₁₀ and size-segregated samples collected from the summit (2060m, altitude) of Mt. Hua in Guanzhong Plain, central China during the winter of 2009 were characterized using a GC/MS technique. Concentrations of sugars, n-alkanes and PAHs in PM ₁₀ are 107±52, 121±63, 7.3±3.4ngm ^-3, respectively. Levoglucosan and fossil fuel derived n-alkanes are more abundant in the air masses transported from southern China than in those from northern China with no spatial difference found for PAHs, suggesting that emissions from biomass burning and vehicle exhausts are more significant in southern part of the country. Dehydrated sugars, fossil fuel derived n-alkanes and PAHs presented a unimode size distribution, peaking at the size of 0.7-1.1μm, whereas non-dehydrated sugars and plant wax derived n-alkanes showed a bimodal pattern, peaking at 0.7-2.1 and 5.8-9.0μm, respectively.Principal component analysis showed that biofuel combustion plus plant emission is the most important source in Mt. Hua, being different from the cases in Chinese urban areas where fossil fuel combustion is the major source. By comparison with previous mountain and lowland observations and aircraft measurements we found that wintertime PAHs in China are still characterized by coal burning emissions especially in the inland regions, although in the country increasing rate of SO ₂ emission from coal combustion has decreased and emissions of vehicle exhaust has sharply increased.