Ultraviolet sunlight

Zinc oxide is an example of zinc(Il) combining with a —2 anion. (Zn + O —> ZnO). Zinc oxide is also added to paints as a pigment and mold inhibitor and is known as zinc white when it is used as an oil paint by artists. It is used for cosmetics (ointment to protect nose and bps from ultraviolet sunlight), as a seed treatment, and as a dietary supplement. 

Long-range effects of having less ozone in the stratosphere involve greater ultraviolet sunlight transmission, alteration of weather, and an increased risk of skin cancer. The ozone depletion potential for CFCs and other fluorocarbons have been measured and are given below relative to CFC-11 and -12. Notice that the HCFCs with lower chlorine content have lower depletion potentials than the CFCs, and the one HFC studied shows no depletion potential because it contains no chlorine. 

There was a ban on chlorqfluorocarbons (CFCs) as aerosol propellants because they may react with ozone in the stratosphere, increase the penetration of ultraviolet sunlight, alter the weather, and increase the risk of skin cancer. CFCs are discussed in Chapter 12, Section 4. 

D3 (cholecalciferol) This is the natural form of vitamin D produced in the skin by ultraviolet sunlight. 

Frederick, J.E. (1993) Ultraviolet sunlight reaching the Earth s surface a review of recent research, Photochem. Photobiol., 57 175-178. 

Photochemistry is also important in present-day planetary atmospheres. The best-known abiotic example is the production of ozone (O3) in the Earth s stratosphere, initiated by the photodissociation of O2 by ultraviolet sunlight ... 

The examples in the previous paragraph all describe the effects of ultraviolet sunlight on planetary atmospheres. These chemical effects are largely confined to the atmospheres, since short-wavelength light is strongly absorbed by molecules. This same property has led to the view that ultraviolet photochemistry was probably not important in the much more massive solar nebula the cloud of gas and dust from which the Sun and planets formed. As a... 

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