What are UV Rays?

UV Rays are a form of ultraviolet radiation generated by the Sun. Ultraviolet rays fall in the middle of the electromagnetic spectrum. There are different types of UV rays which all fall on the spectrum from short (high frequency) to long (low frequency) rays. UV rays are ionizing radiation and they fall into three categories: UVA, UVB and UVC. Ionizing radiation is radiation that has enough energy to ionize. To ionize is to remove an electron from an atom or molecule. This is the process by which a free-radical is created.

UVA rays are the lowest frequency UV rays and they penetrate deeper into the skin. They cause tanning, photoaging and premature wrinkling.

UVB rays are a higher frequency than UVA rays. They do not penetrate as deeply as UVA rays but they can be more damaging. They cause redness, sunburns and contribute to skin cancer. UVB rays can directly damage the DNA in skin cells.

UVC rays react with the ozone layer so they do not reach us.

References

https://www.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation.html

https://www.iso.org/standards.html

https://physics.info/em-spectrum/