Ultraviolet radiation skin protection

Darr D, Combs S, Dunston S, Manning T, Pinnel S (1992) Topical vitamin C protects porcine skin from ultraviolet radiation-induced damage. Br J Dermatol 127 247-253... 

Sunscreens are transparent organic substances that penetrate into the skin and absorb ultraviolet radiation. Common classes of sunscreens include benzophe-nones, PABA derivatives, cinnamates, salicylates, and dibenzoylmethanesJ3 Ben-zophenones have a primary protective range in the UVA region and include oxy-benzone (Fig. 12.9.1), 270-350 nm dioxybenzone (Fig. 12.9.2), 206-380 nm ... 

Several studies have linked lutein to a lower risk for eye, skin and other health disorders, probably through its antioxidant activity. Lutein is apparently metabolized to zeaxanthin, an isomer, and several other compounds which protect the macula from ultraviolet radiation. The suggestion is that lutein may play a positive role in reducing macular degeneration. Other reports have linked lutein to a reduction of risk of cancer.13 Regardless, lutein is currently being promoted as an important dietary supplement. 

Sunscreens absorb ultraviolet radiation before it can be absorbed in the skin. They are recommended to protect the skin from the major toxicities of sun exposure sunburn and skin cancer. Most available agents primarily absorb UVB, although newer preparations also provide protection against UVA. Physical sunscreens (which are generally opaque, hke titanium dioxide and zinc oxide) block all ultraviolet radiation. 

All fine chemicals are used for making speciality chemicals, either by direct formulation or after chemical/biochemical transformation from intermediates to active substances. Specialty chemicals are solid (e.g., tablets) or liquid (e.g., solutions) mixtures of commodities or fine chemicals and exhibit specific properties. They are sold on the basis of what they can do (e.g., protect the skin against ultraviolet radiation), rather than on what they are (e.g., molecular structure 2-ethyl-hexylmethoxycinnamate). Within specialties, pharmaceuticals and other life science products use the largest amount of fine chemicals. They are described in detail in Sections 11.1-11.3. Uses of fine chemicals outside life sciences are discussed in Section 11.4. 

For example, persons with xeroderma pigmentosum are deficient in enzymes that repair DNA damage done by ultraviolet radiation, and they develop skin tumors on areas of the body exposed to sunlight. For their own protection, they should not be farmers, cowboys, or lifeguards on sunny beaches. Some chemicals mimic ultraviolet radiation in their effects on DNA, and such persons are expected to be especially susceptible to them. 

Ozone is O3. The ozone layer is a region of the stratosphere that contains higher concentrations of ozone than other parts of the atmosphere. The ozone layer is important for human health because it blocks ultraviolet radiation from the sun, and this helps to protect us from skin cancer. Research in the 1970s revealed that several gases used for refrigeration and other purposes were depleting the ozone layer. Many of these ozone-destroying molecules are short alkyl halides known as chlorofluorocarbons or CFCs. 

In 1993, a scientific link was established between ozone depletion and increases in ultraviolet radiation. It was found that increased exposure to UV-B radiation causes skin cancer, the formation of cataracts, and the suppression of the human immune system. Research has shown skin cancer to be as common as all other types of cancer combined. Sunscreens can protect humans from the risk of some skin cancers. Unfortunately they do not appear to provide protection against damage to the immune system. 

You come into contact with many different kinds of electromagnetic radiation in your daily life. For example, you use visible light to see the words on this page, you may cook with microwaves, and you should use sunscreen to protect your skin from the harmful effects of ultraviolet radiation. 

Ozone is vital to life it acts like a shield, protecting the earth s surface from destructive ultraviolet radiation. A decrease in ozone concentration in this protective layer would have some immediate consequences, including an increase in the incidence of skin cancer and eye cataracts. Other long-term effects include a reduced immune response, interference with photosynthesis in plants, and harmful effects on the growth of plankton, the mainstay of the ocean food chain. 

The reactor must he properly screened. Wear special protective goggles, or better still a face shield which offers protection against ultraviolet radiation if the apparatus is to be adjusted (or samples taken) while the lamp is on. When doing this also protect the hands with gloves and make sure that no other areas of skin would be exposed to radiation in... 

SPF is the ratio of the length of time of solar radiation exposure required for the skin to show redness (erythema) with and without protection. The term SPF or UPF (ultraviolet protection factor) has been introduced such that a garment of UPF 15 will provide the same amount of protection against solar ultraviolet radiation as a sunscreen of SPF 15. Garments with a UPF value of 20-29 offer high protection (UVR transmission 5.0-3.3%). A UPF value of 30-40 (UVR transmission 3.3-2.5%) offers very high protection and a UPF value of 40 + offers maximum protection with a UVR transmission of 2.5%. 

As we can clearly see from Figure 8.13 TiO particles absorb the ultraviolet radiation and prevent this type of radiation from reaching the skin offering protection from the suns rays that can cause skin cancer. 

The early test methods for determining the ultraviolet protective effects of clothing involved exposing volunteers to ultraviolet radiation until their skin reddened (erythema) to a specific degree. Fortunately, instrumental methods of evaluation have been developed that eliminate the need for sunburned assistants. AATCC Test Method 183-20005 determines the transmittance of ultraviolet light through fabric samples. Through the use of established tables and formulas, the UPF is calculated. 

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