UVA is the UV wavelength 320-400 nm
Just a little UVA in the filter by ozone, mostly down to the surface of the earth, UVA is also able to penetrate the glass, and in humans the UVA rays penetrate deep into the skin (collagen)
UVB is UV with a wavelength of 280-320 nm
Most UVB filtered / absorbed by ozone, UVB has an effect on the outer skin of humans.
According to NASA research scientist (Paul A. Newman), the Earth's ozone levels between 2000 to 2013 increased by 4%.
Sun Protection Factor (SPF) measures a sunscreen’s ability to filter UVB rays.
UVA / UVB rays are the cause of skin cancer, so we need a sunscreen that can protect us from these two aspects that are harmful to our skin.
Broad spectrum is the ability to protect against UVA and UVB. Sunscreen that has the label "broad spectrum" that is worth buying.
Uses an SPF minimum 15 (higher better) sunscreen with the active ingredient zinc oxide, a natural ingredient that physically—instead of chemically—blocks rays. Another benefit using natural ingredient is it working instantly after you applied to your skin, the chemical ingredient need 15/20 minute to work because it need to absorb by skin. If you do not like a natural sunscreen because of performance problems, then you can use natural tinted sunscreen. Zinc oxide protects against both UVA and UVB rays.