Which rays from the sun are primarily responsible for causing sunburns?

The reason UVB rays are primarily responsible for causing sunburns lies in their specific wavelength and how they interact with the skin. UVB rays have a shorter wavelength compared to UVA rays and are more intense, particularly during the peak sunlight hours. They penetrate the outer layer of the skin and cause damage that can lead to the reddening and burning sensation characteristic of sunburn.

The action of UVB rays on the skin triggers an inflammatory response, which manifests as sunburn. This important distinction highlights the role of UVB in direct skin damage, which is less prominent with UVA rays. While UVA rays contribute to skin aging and the formation of certain types of skin cancer, they are not as effectively linked to the immediate effects like sunburn. Infrared rays and visible light rays do not cause sunburn as they do not have the wavelength necessary to damage the epidermis in the same way that UV rays do.