What is UVA?

Thanks for your question. UVA stands for Ultra Violet A Rays. UVA is just below visible light spectrum at 320 to 400nm wavelength. UVA is a  relatively long wavelength and accounts for approximately 95 per cent of the UV radiation reaching the Earth’s surface. It can penetrate into the deeper layers of the skin and is responsible for the immediate tanning effect.

UVB is required for the production of melanin from the melanocytes in your first layer of skin, this is what starts your photoprotection or tan.