What is the difference between UV and UVC light?

Light is fundamentally electromagnetic waves of various wavelengths. The UV range of the electromagnetic radiation spectrum is from 10nm to 400 nm. UVC is just one part of the UV spectrum. The UV spectrum has three broad categories: UVA (315nm-400nm), UVB(280nm -315nm), UVC(200nm – 280nm).

 Each UV band damages skin and poses risks for humans in different ways, depending on the wavelength and exposure times of light. Using broad-spectrum Sunscreen and tinted UV protective film in windows can help protect yourself from the sun’s harmful UV rays. Short wavelengths are more detrimental to cells. Luckily shorter wavelengths have minimal ability to penetrate the skin-saving us from much damage. 

UVA radiation – This accounts for 95% of the UV radiation that reaches earth. It can penetrate deeper layers of skin up to the second layer. Used for immediate tanning and plays a crucial part in skin aging and wrinkling.

UVB radiation- Atmosphere filters most of the UVB radiation. The intensity depends on the season, location, and time of the day. It can penetrate the top layer of skin and responsible for damaging the skin’s DNA linking it to increased skin cancer risk. It can burn unprotected skin and tan the skin in less than 15 min.

UVC radiation – The most damaging UV radiation. It has germicidal effects on microorganisms. No natural UVC radiation reaches the surface of the earth because of ozone. UVC radiation has low absorption length in human skin; almost all absorption happens in dead cell layers; some UVC radiation can reach the living cells in the skin. Radiation effects include redness or ulcers in the skin—severe acute damage to the eye can result in cornea injury. High levels can cause severe burns. Long term exposures can result in premature aging of skin or skin cancer.

People working in UV radiation environments should wear Personal Protective Equipment (PPE),  UV glasses or face shields, gloves. Brief exposure to UV radiation is usually not severe and can result in delayed symptoms. Consult a doctor if you suspect eye or skin damage after accidental exposure to UV radiation.


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