Weathering release occurs of Ca and other ions into surface waters. Rainfall is acidic because atmospheric carbon dioxide dissolves in the rainwater producing weak carbonic acid. In unpolluted environments, the rainfall pH is around 5.6. Acid rain occurs when gases such as sulfur dioxide and nitrogen oxides are present in the atmosphere. These oxides react in the rain water to produce stronger acids and can lower the pH to 4.5 or even 3.0. Sulfur dioxide, SO, comes from volcanic eruptions or from fossil fuels, can become sulfuric acid within rainwater, which can cause solution weathering to the rocks on which it
Factors of polymer weathering hydrocarbons from automobile exhausts is another source. Ozone plays a dual role in weathering. The concentrated layer in the upper atmosphere absorbs the short wavelength (≤300 nm) ultraviolet radiation emitted by the sun and thus plays a critical role in protecting terrestrial objects from this actinic radiation. Ozone is also a powerful oxidant and reported to react rapidly with elastomers and other unsaturated polymers. Ozonolysis typically results in stiffening and cracking, particularly under mechanical stress. However, the contribution of ozonolysis reactions to the overall photooxidation process is still subject to controversy. Atmospheric pollutants (e.g., sulfur dioxide, nitrogen oxides, hydrocarbons, etc.),