Atmospheric particulate organic matter, sources

Dalsey, J. M. Knelp, T. J. "Atmospheric Particulate Organic Matter Multivariate Models for Identifying Sources and Estimating Their Contributions to the Ambient Aerosol", This Symposium. 

Particulate matter is the term used to describe solid particles and liquid droplets found in the atmosphere. Particulates are produced by a host of natural and anthropogenic sources. Mist and fog are both forms of natural particulates, as are windblown soil, dust, smoke from forest fires, and biological objects, such as bacteria, fungal spores, and pollen. The incomplete combustion of fossil fuels is one of the most important anthropogenic (human-made) sources of particulates. Such processes release unhurned carbon particles, oxides of sulfur and nitrogen, and a host of organic compounds into the air. 

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)... 

The most abundant hydrocarbon in the atmosphere is methane, CH4, released from underground sources as natural gas and produced by the fermentation of organic matter. Methane is one of the least reactive atmospheric hydrocarbons and is produced by diffuse sources, so that its participation in the formation of pollutant photochemical reaction products is minimal. The most significant atmospheric pollutant hydrocarbons are the reactive ones produced as automobile exhaust emissions. In the presence of NO, under conditions of temperature inversion (see Chapter 16), low humidity, and sunlight, these hydrocarbons produce undesirable photochemical smog, manifested by the presence of visibility-obscuring particulate matter, oxidants such as ozone, and noxious organic species such as aldehydes. 

Emissions to the atmosphere from ammonia plants include sulfur dioxide (SOj), nitrogen oxides (NOJ, carbon monoxide (CO), carbon dioxide (COj), hydrogen sulfide (HjS), volatile organic compounds (VOCs), particulate matter, methane, hydrogen cyanide, and ammonia. The two primary sources of pollutants, with typical reported values, in kilograms per ton (kg/t) for the important pollutants, are as follows ... 

Primary organics are emitted to the atmosphere by industrial sources (oil refineries, chemical plants, producers and users of solvents and plasticizers), vehicles (as a result of incomplete fuel combustion, oxygenated degradation products of lubricating oil, polymers from tires), and agricultural activities (use of pesticides). An exhaustive literature survey is beyond the scope of this section, but can be found in Air Quaiity Criteria for Particulate Matter many useful references are also available. 

Organic compounds, natural, fossil or anthropogenic, can be used to provide a chemical mass balance for atmospheric particles and a receptor model was developed that relates source contributions to mass concentrations in airborne fine particles. The approach uses organic compound distributions in both source and ambient samples to determine source contributions to the airborne particulate matter. This method was validated for southern California and is being applied in numerous other airsheds. ... 

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