SUN EXPOSURE

   Ultraviolet (UV) rays are a part of sunlight that is an invisible form of radiation. UV rays can penetrate and change the structure of skin cells. There are three types of UV rays: ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC). UVA is the most abundant source of solar radiation at the earth's surface and penetrates beyond the top layer of human skin. Scientists believe that UVA radiation can cause damage to connective tissue and increase a person's risk for developing skin cancer. UVB rays penetrate less deeply into skin, but can still cause some forms of skin cancer. Natural UVC rays do not pose a risk to workers because they are absorbed by the Earth's atmosphere.

   Sunlight exposure is highest during the summer and between 10:00 a.m. and 4:00 p.m. Working outdoors during these times increases the chances of getting sunburned. Snow and light-colored sand reflect UV light and increase the risk of sunburn. At work sites with these conditions, UV rays may reach workers' exposed skin from both above and below. Workers are at risk of UV radiation even on cloudy days. Many drugs increase sensitivity to sunlight and the risk of getting sunburn. Some common ones include thiazides, diuretics, tetracycline, doxycycline, sulfa antibiotics, and nonsteroidal anti-inflammatory drugs, such as ibuprofen.

   Workers at increased risk of UV damage from sun exposure include lifeguards, construction workers, agricultural workers, landscapers, gardeners, and other outdoor workers.

   Source: http://www.cdc.gov/niosh/topics/sunexposure/default.html

Vocabulary:

sunlight: luz solar

estructure: estrutura

skin: pele

cells: células

layer: camada

tissue: tecido

increase: aumento

developing: em desenvolvimento

deeply: profundamente

even: mesmo

sunburn: queimadura do sol

tetracycline: tetraciclina

lifeguards: salva-vidas

landscarpers: paisagista.