UVA radiation

UVA accounts for 95% of all of UV radiation reaching the Earth. UVA rays are present during all daylight hours and penetrate both cloud and windows. UVA rays are the dominant tanning rays. They have long been known to cause skin aging and wrinkles. A tan is the result of injury to the skin’s DNA and the skin darkens in an imperfect attempt to prevent further DNA damage. This process is now known to lead to the development of skin cancer. 

UVB radiation 
UVB rays are responsible for skin reddening and sunburns. These rays cause both skin cancers and skin aging. UVB rays damage your skin year-round. When reflected off a shiny surface such as water, they are 80% stronger than when coming directly from the sun. UVB rays do not penetrate glass significantly. 

Tanning Beds 
The high-pressure sunlamps used in tanning salons emit up to 12 x UVA as the sun. People who use tanning beds are up to 2.5 x more likely to develop skin cancer. Exposure to tanning in beds in young age is particularly linked to an increase in malignant melanoma. 

Sunscreens 
Someone using a broad spectrum sunscreen of SPF 30 correctly will take 30 times longer to get a sunburn than someone not using sunscreen. An SPF 30 sunscreen will protect against 97% of UV rays, while a SPF 50 sunscreen will protect against 98% UV rays. 

There are 2 types of sunscreens: chemical and physical. 
Chemical sunscreens contain nano-particles that absorb light in both the UVA and UVB spectrums and transform this light into harmless radiation, re-emitted as heat energy. 

An example of physical sunscreen is zinc oxide. This forms a physical barrier between your skin and UV radiation. 

A broad-spectrum sunscreen will provide both chemical and physical protection against both UVA and UVB radiation and has an SPF 30 or higher. SPF is sun protective factor and is an internationally standardised measure of sunscreen’s ability to filter UV radiation.

According to the cancer council of Australia and the TGA (Theraputic Goods Association), the nanotechnology used in sunscreens for many years do not pose a health risk. The nanoparticles have not been shown to have access to viable skin cells. They remain on the surface of the epidermis of skin until they are washed or sloughed away.