Temporal And Spatial Distributionsource And Environmentalsignificance Of Biogenic Aerosol:

Biogenic aerosol play an important role in climate by directly scattering orabsorbing solar radiation, and indirectly serve as ice nucleators (IN) and cloudcondensation nuclei (CCN), and have a potential impact on atmospheric chemical andphysical processes. The biological fraction of particulate matter lead to acute andchronic human diseases and animal diseases through diffusion and transmission. Inthis paper the following two aspects investigate biogenic aerosol. The section focuseon polar sulfur aerosols in marine boundary layer from the first to the sixth chapter.The seventh chapter discuss the city bioaerosol associated with human health.Sulfur is one of the most important elements whose biogeochemical cycles arepivotal to the atmospheric environment and to the climatic changes. The dimethylsulfide (DMS) emitted by microorganisms in the surface water of ocean, be oxidizedto produce methanesulfonate (MSA) and sulfate (SO₄^2-) as two major end products.The concentration of MSA, Nss-SO₄^2-, trace elements, and water-soluble ionscollected during the 3rdChina Arctic, the 24thand 26thChina Antarctic Researchexpedition, and areas of China, combined with air mass back trajectories, SRIFs,chlorophyll, SO2, meteorological data, and sulfur aerosol in other ocean referenced inprevious reports, discuss the distribution characteristic, sources and environmentalsignificance. The data update the concentration of marine sulfur aerosol in recentyears, explore the reasons for inter-annual variation. The sampling and analysis acrosslong period and a wide range from Norh to South hemisphere, summarize the maininfluence factors to sulfur aerosols. The main conclusions are as follows:(1)The concentration of MSAin MBL are higher than previously observationsin the same area during the Chinese polar and offshore research expedition, and MSAin Northern hemisphere exceed Southern. The important factor is enhanced seasurface temperature increase marine productivity. Nss-SO₄^2-concentration close toland increase significantly, little change in other oceans.(2)There are differences of MSAin Northern hemisphere, the concentration arerelative high in Bering Sea over Northwestern Pacific Ocean. In Southern hemisphere,distribution of MSA is consistent, and the Southern Ocean slightly higher.(3)The sea ice cover and thickness decreases in response to global climate change, make the open ocean to increase and large area growth of algae, enhance theair-sea exchange, organic sulfur emitted from phytoplankton greatly increase. Theseare the cause that MSA in Arctic Ocean and Southern Ocean are greater than data inpervious years.(4)The concentrations of NO_xwill improve the efficiency of the oxidation ofDMS. Polluted air with high NO_xgives higher MSA yields. Significant amounts ofanthropogenic NO_x can be transported to coastal China Sea.(5)The concentrations of Nss-SO₄^2-are low in remote ocean, have obviouspositive relationship with MSA especially in Southern Ocean, conclude that marinebiological emissions are the main source. Nss-SO₄^2-concentrations are high close toland and have no connection with MSA. The long-distance transport of sulfur oxidesgenerated by anthropogenic pollution is an important contributor.(6)The large amounts of SO2released from volcanic eruptions would beoxidized into sulfate aerosols, have great impact on Nss-SO₄^2-in the surroundingregions. During the Arctic expedition, volcanic erupting in Kasatochi, Alaska havesignificant influence to Nss-SO₄^2-in Arctic.(7)Precipitation and windy weather conditions have strong erosion and blendeffect on particulate matter, greatly dilute the concentration of sulfur aerosols.In the seventh chapter, a preliminary investigation about the urban biologicalaerosols been carried out. The total protein associated with bioaerosol particulatematter (PM) is generally measured as an all-inclusive indicator of airborne biologicalmaterial, which may enhance the effects of allergens, allergic and asthmatic responses.To investigate the level and seasonal variations of biological loading, PM10werecollected in a metropolitan area of Hefei, and analyzed for total protein mass, traceelements, and water-soluble ions. The protein concentration in PM10ranged from 2.08to 36.71μg m-3with an average of 11.42μg m^-3. Study found that:(1)The totalprotein was found to have a significant correlation with air pollution index (API) andmean visibility (VV), indicating the potential influence of anthropogenic sourcesand/or crustal sources.(2)The protein content displayed an obvious seasonalvariation with respect to weather conditions. In the rainy season the level of proteinwas low, while in the dry season and foggy weather the level of protein was relativelyhigh.(3)An correlation analysis revealed that the relationship between total proteinconcentration andwater-soluble ions K+and NO3-in PM10during the dry season are0.92 and 0.66 (P<0.05), respectively, suggesting that anthropogenic pollution and biomass burning are main contributors during this period.