Annual atmosphere aerosol production

It is our estimate that all pollutant sources result in about 300 X 10 tons per year of particulate material being introduced into the atmosphere and that pollutant and natural sources combined amount to about 3000 X 10 tons per year. Thus, on a global scale 30 X 10 tons per year of pollutant photochemical aerosols are about 10% of the total pollutant aerosols and about 1% of the total annual atmospheric aerosol production. The 200 X 10 tons of aerosol particles resulting from the photochemical scavenging reactions involving natural organic emissions is somewhat less than 10% of the total aerosols emitted to the global atmosphere. 

The major ions have two main escape routes from the ocean (1) incorporation into sediments or pore water and (2) ejection into the atmosphere as seasalt spray. This spray is caused by bursting bubbles that produce small particles, called aerosols, that range in diameter from 0.1 to 1000 pm. The annual production rate of seasalt aerosols is large, on the order of 5 x lO kg/y, but virtually all of it is quickly returned when the spray fells back onto the sea surfece. A small fraction (about 1%) is deposited on the coastal portions of land masses and carried back into the ocean by river runoff. As shown in Table 21.6, seasalts represent a significant fraction of dissolved solids in river runoff, especially for sodium and chloride. Due to the short timescale of this process, seasalt aerosol losses and inputs are considered by geochemists to be a short circuit in the crustal-ocean-atmosphere fectory. The solutes transported by this process are collectively referred to as the cyclic salts. ... 

The chlorofluorocarbon compounds of methane and ethane are collectively known as freons. They are extremely stable, unreactlve, non-toxic, non-corrosive and easily liquefiable gases. Freon 12 (CCI2F2) Is one of the most common freons In Industrial use. It Is manufactured from tetrachloromethane by Swarts reaction. These are usually produced for aerosol propellants, refrigeration and air conditioning purposes. By 1974, total freon production In the world was about 2 billion pounds annually. Most freon, even that used In refrigeration, eventually makes Its way Into the atmosphere where It diffuses unchanged Into the stratosphere. In stratosphere, freon Is able to Initiate radical chain reactions that can upset the natural ozone balance (Unit 14, Class XI). 

Methylene chloride is a widely used industrial chemical with reported atmospheric emissions of more than 126 million pounds annually in the United States. The principal route of exposure for the general population to methylene chloride is by inhalation. Occupational and consumer exposure to methylene chloride commonly occurs from spray painting and contact with consumer products such as paint strippers or aerosol cans, that contain methylene chloride. Exposures may occur as a result of breathing the vapors given off by the product or from direct dermal contact. Occupational exposure to methylene chloride by the inhalation route offers the most opportunity for exposure but it can also be absorbed through the skin. 

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