Sources of Atmospheric Particulate Matter

Wildfires represent a major source of atmospheric particulate matter (PM) especially fine particles with diameter <2.5 pm (PM2.5). High ambient fine particle concentrations are associated with serious health problems [4], At times extensive... 

Table 4-5 shows the major sources of atmospheric particulate matter, for different aerosols and aerosol precursors. 

The Beijing area in north China is well situated for investigating relationships between the elemental composition of atmospheric particulate matter and air mass movements. The municipality of Beijing (Beijing shi) has a population of 7 million, half of whom live in the city proper, and pollution sources of trace gases... 

With modem methods of analysis of atmospheric particulate matter, especially neutron activation, one can determine atmospheric concentrations of vanadium in remote locations. Comparisons of vanadium concentrations with those of other elements in remote areas suggest that much of the observed vanadium orignates from mans activities. Atmospheric vanadium concentrations in most United States cities are less than 20 ngrams/meter, but many cities in the northeastern United States have up to several figrams/meter. A study of Boston shows that residual fuel combustion is the only source of vanadium of sufficient magnitude to produce the concentrations observed. Because of the high sensitivity for its analysis, vanadium can serve as an indicator of wide-scale movement of particulates from this identified anthropogenic source. 

Estimations of global emissions, as reported by many authors, have shown that natural and anthropogenic sources can contribute to the principal dimensional classes (coarse, fine and ultrafine) of atmospheric particulate matter (PM). About 10-20 % of the aerosols can be characterized as anthropogenic on a global scale, but these values may drastically change due to local scenarios, human activities and the prevailing particle cut-off. 

Historically, the sulfur oxides have long been known to have a deleterious effect on the atmosphere, and sulfuric acid mist and other sulfate particulate matter are well established as important sources of atmospheric contamination. However, the atmospheric chemistry is probably not as well understood as the gas-phase photoxidation reactions of the nitrogen oxides-hydrocarbon system. The pollutants form originally from the S02 emitted to the air. Just as mobile and stationary combustion sources emit some small quantities of N02 as well as NO, so do they emit some small quantities of S03 when they bum sulfur-containing fuels. Leighton [2] also discusses the oxidation of S02 in polluted atmospheres and an excellent review by Bulfalini [3] has appeared. This section draws heavily from these sources. 

Another potential source of atmospheric radium is particulate matter created by uranium mining and milling operations. However, no information was located on estimated releases or atmospheric concentrations. 

Atmospheric particles influence the Earth climate indirectly by affecting cloud properties and precipitation [1,2], The indirect effect of aerosols on climate is currently a major source of uncertainties in the assessment of climate changes. New particle formation is an important source of atmospheric aerosols [3]. While the contribution of secondary particles to total mass of the particulate matter is insignificant, they usually dominate the particle number concentration of atmospheric aerosols and cloud condensation nuclei (CCN) [4]. Another important detail is that high concentrations of ultrafine particles associated with traffic observed on and near roadways [5-7] lead, according to a number of recent medical studies [8-11] to adverse health effects. 

The presence of heavy metals in the atmospheric particulate matter in Antarctica can be attributed to different sources, both natural and anthropogenic. Some authors state that almost all natural sources of heavy metals in Antarctica are generally situated in the southern hemisphere (4, 14, 15). The natural sources are normally volcanic activities, erosive processes, continental dusts, marine spray from the ocean, low-temperature biological processes, etc. (7, 10, 16-18). Important local human sources of heavy metal emissions into the Antarctic atmosphere are presumed to be the Antarctic stations and their activities, especially all kinds of transport, power plants, waste burning (incinerators), etc. (10, 12, 15, 19). 

Most of the direct releases of PAHs to the environment are to the atmosphere from both natural and anthropogenic, sources, with emissions from human activities predominating. PAHs in the atmosphere are mostly associated with particulate matter however, the compounds are also found in the gaseous phase (NRC 1983 Yang et al. 1991). The primary natural sources of airborne PAHs are forest fires and volcanoes (Baek et al. 1991 NRC 1983). The residential burning of wood is the largest source of atmospheric PAHs (Peters et al. 1991 Ramdahl et al. 1982) releases are primarily the result of inefficient combustion and uncontrolled emissions (Freeman and Cattell 1990 NRC 1983 Tan et al. 1992). Other important stationary anthropogenic sources include industrial power... 

Understanding heterogeneous chemistry (4) the structure of natural organic matter (2) air sources and characterization of toxics (1) speciation of toxic metals (1) smokestack emissions beyond SOx and NOx (1) chemical sources of toxicity of fine particulate matter (PM2.5) (1) environmentally persistent free radicals (1) understanding of greenhouse gases in the atmosphere (carbon cycles and sinks)... 

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