Organic matter terrestrial weathering

The terrestrial weathering of organic matter derived from shales and soils results in the oxidation of carbon, which generates CO2. Dissolution of this CO2 in water produces carbonic acid. This weak acid serves to enhance chemical weathering reactions... 

Humic substances constitute the bulk of the organic matter in most terrestrial soils. The functions they perform are multiple and varied and include the weathering of rocks and minerals, mobilization and transport of metal ions, and formation of stable aggregates by combination with clay minerals. Humic substances make a significant contribution to the cation-exchange capacity of the soil, and they are involved in the sorption of organic molecules applied to soils as pesticides. 

Atmospheric Pollutants. Ozone is present in the earth s atmosphere both as a result of uv photolysis of oxygen in the upper atmosphere and as a result of reaction between terrestrial solar radiation and atmospheric pollutants such as nitrogen oxides and hydrocarbons from automobile exhausts. It is a powerful oxidant that can react rapidly with elastomers and other imsatin-ated polsrmeric materials to cause stiffening and cracking, particularly imder mechanical stress. Other common air pollutants include sulfur oxides, hydrocarbons, nitrogen oxides, and particulate matter such as sand, dust, dirt, and soot. Some of these may react directly with organic materials, but have a much more severe effect in combination with other weather factors. 

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