Emissions natural biogenic

Other sources of river sulfate Include natural biogenic emissions to atmosphere delivered to land in rain (3%), votanism (8%) and pyrite weathering (11 %). 

The sum of EC and OM contributes another 20-27% (at urban sites) and 18-24% (rural) to the PM mass, with OM dominating EC at most sites. Like in the case of SIA, differences between rural and urban sites appear modest which is probably caused by a considerable natural (biogenic) input. A study by ten Brink et al. [13] on the presence of 14C in PM filter samples revealed that at least 64% of the organic carbon measured at an urban Dutch site was contemporary (i.e. emissions from biogenic material and biomass wood combustion). 

O Dowd C, Jimenez JL, Bahreini R, Flagan RC, Seinfeld JH, Hameri D, Pirjola L, Kulmala M, Jennings SG, Hoffmann T (2002) Marine aerosol formation from biogenic iodine emissions. Nature 417 632... 

Pyrogenic and natural biogenic emissions to the atmosphere in the Amazon basin may have an impact on the global tropospheric chemistry, because this region exhibits intense convective activity that injects gases and aerosols to high altitudes where they can be transported over long distances (Andreae et al. 1996, 1998, Echalar et al. 1998). Elemental concentrations in aerosols from Amazonia and Africa are very similar (Artaxo... 

During the Amazonian wet season, rainwater chemistry is dominated by natural biogenic emissions, consisting mostly of... 

The physical and chemical status of the atmosphere is called climate (see Chapter 3.2 for details). Considering that the incoming solar radiation shows no trend over several hundred years, and accepting that natural biogenic and geogenic processes vary but also do not show trends on these time scales, it is only mankind s influence on land use and emissions into the atmosphere that changes air chemical... 

There are also significant natural sources of oxides of nitrogen, in particular nitric oxide, which is produced by biomass burning as well as by soils where nitrification, denitrification, and the decomposition of nitrite (N02) contribute to NO production. Figure 2.4b, for example, shows the relative emission rates for biogenically produced NO in the United States in 1990 (EPA, 1995). 

Table 2.1 gives an estimate for global-scale natural and anthropogenic emissions of NOx as well as of CO, CH4, and VOC (Muller, 1992). It is seen that biomass burning and biogenic emissions of NO are comparable and together equal to about half of the anthropogenic emissions. 

Natural emissions of sulfur compounds to the atmosphere occur from a variety of sources, including volcanic eruptions, sea spray, and a host of biogenic processes (e.g., Aneja, 1990). Most of the volcanic sulfur is emitted as S02, with smaller and highly variable amounts of hydrogen sulfide and dimethyl sulfide (CH3SCH3). Sea spray contains sulfate, some of which is carried over land masses. 

The composition and sources of particles are discussed in detail in Chapter 9. Major natural sources of particles include terrestrial dust caused by winds, sea spray, biogenic emissions, volcanic eruptions, and wild-... 

Konig, G., M. Brunda, H. Puxbaum, C. Hewitt, C. Duckham, and J. Rudolph, Relative Contribution of Oxygenated Hydrocarbons to the Total Biogenic VOC Emission of Selected Mid-European Agricultural and Natural Plant Species, Atmos. Enriron., 29A, 861-874(1995). 

The relative importance of biogenic emissions depends on the nature of the air mass into which they are... 

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