Abstract
Abstract Air pollutant long-range transport has received increased attention in recent years (Wang, Tsay et al. 2011). With the aid of westerlies, aerosol emissions from China (such as from urban and industrial centers), as well as biomass burning (BB) emissions from south-east Asia can be easily transported to Taiwan, which is located in the outflow region of the Asian continent. Here, biomass burning emissions from Indochina have been investigated upon long-range transport at two sampling sites: a site near the biomass burning sources in Sonla Province, Vietnam, and a receptor/background site, Mt. Lulin, Taiwan. Near-source observations of fresh smoke emissions from various burning processes allowed the chemical and physical characterization of source emissions and the comparison with ambient aerosol potentially influenced by such smoke emissions upon long-rang transport at a downwind site in Taiwan. Primary Bioaerosols PBAs (including pollen, fungal spores, bacteria, viruses, and fragments of animals and plants) could influence precipitation and energy budget of the earth by acting as cloud condensation nuclei and ice nuclei, while also playing an important role in the transport of trace elements and pathogens into and away from specific biomes. Fungal spores are considered to be the most dominant fraction of bioaerosols in the size range 2-10 µm, and are able to survive even harsh environmental conditions. However, a study of fungal material in fine particulate matter would be more essential, since fine aerosaol particles (with aerodynamic diameters < 2.5 μm, PM2.5) could easily get though respiratory tracts and reach deeply to human lungs, cause more severe symptoms when entering the blood stream at the alveoli. BB processes across the globe release large amounts of aerosols, causing visibility impairment, adversely affecting human health, and contributing to climate change. Furthermore, in this study, we found BB emissions to also interact with microbial activities, affecting fungal spore release, about which very little is known. This work is based on three main aims: 1. Biomass burning source emissions characterization 2. Assessment of BB emission long-range transport 3. Investigation of BB-Fungal spore interactions. Results from the near-source aerosol characterization in the biomass burning source region, i.e., at the Son La site in northern Vietnam showed that particulate mass in PM2.5 accounted for 75% of the PM10 mass, with high organic carbon (OC) concertrations compared to elemental carbon (EC), indicating the dominance of smoldering over flaming fire regime during the entire dry season. The relative abundance of particulate components, specifically the diagnostic ratios of BB tracers – levoglucosan/mannosan and levoglucosan/K+ – help to further classify the biomass types and show that the burning source was likely a mixture of wood and agricultural residues. The investigation of the BB-fungal spore interactions revealed that at the near-source site, Son La, levoglucosan exhibited excellent correlations with fungal spore tracers (arabitol, mannitol and xylitol) in fine particle fraction. Characterization of the ambient aerosol at the high-altitude station at Mt. Lulin (LABS), Taiwan, acting as a downwind receptor site, allowed to see the effects of BB on fungal activity after long-distance transport. It was revealed that the fungal spore tracers arabitol and mannitol appeared in PM2.5 only during the biomass burning season, while they were always present in PM10, with the fungal tracers exhibiting better correlation with levoglucosan in PM2.5 than in PM10. However, during periods when the air masses were advected from the BB region according to the back trajectory analysis, levoglucosan showed better correlation with fungal spore tracers in PM10, indicate that local fungal activities could be affect by biomass burning activities even after a long-distance of transport