NIOSH Sun Exposure Fast Facts

A quick guide for protecting against the harmful effects of UV rays even on cloudy days.

Protecting Yourself from Sun Exposure

Anyone working outdoors is exposed to the sun’s ultraviolet (UV) rays, even on cloudy days. UV rays are a part of sunlight that is an invisible form of radiation. There are three types of UV rays. UVA is believed to damage connective tissue and increase the risk for developing skin cancer. UVB penetrates less deeply into the skin, but can still cause some types of skin cancer. Natural UVC is absorbed by the atmosphere and does not pose a risk.

Sunburn

Sunburn is not immediately apparent. Symptoms usually start about 4 hours after sun exposure, worsen in 24–36 hours, and resolve in 3–5 days. They include red, tender and swollen skin, blistering, headache, fever, nausea, and…