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
Titanium dioxide nitrogen oxides. A cement that uses titanium dioxide as a photocatalytic component, produced by Italcementi Group, was included in Time Magazine's Top 50 Inventions of 2008. Attempts have been made to photocatalytically mineralize pollutants (to convert into CO and HO) in waste water. TiO offers great potential as an industrial technology for detoxification or remediation of wastewater due to several factors: The photocatalytic destruction of organic matter is also exploited in photocatalytic antimicrobial coatings, which are typically thin films applied to furniture in hospitals and other surfaces susceptible to be contaminated with bacteria, fungi and viruses. Although TiO pigment does