1. Sunscreen can indeed effectively prevent sunburn. It forms a protective film on the surface of the skin through chemical or physical means, blocking or absorbing ultraviolet (UV) radiation and reducing the damage of UV to the skin.
2. The sun protection effect of sunscreen depends on its SPF (sun protection factor) and PA (UVA protection level) values. The higher the SPF value, the stronger the protection against UVB (medium wave ultraviolet); The more plus signs after PA, the better the protection against UVA (long wave ultraviolet). Proper use and reapplication of sunscreen can significantly reduce the risk of sunburn, tanning, and skin aging and lesions caused by ultraviolet radiation.
3. However, sunscreen is not omnipotent, and its sun protection effect is also influenced by various factors, such as usage methods (whether the application amount is sufficient, whether it is evenly applied, whether it is applied before going out, etc.), environmental factors (such as long-term outdoor activities, swimming, sweating, etc. that may reduce the sun protection effect), and personal skin type. While using sunscreen, other sun protection measures should also be taken, such as wearing a hat, wearing long sleeved clothing, and avoiding going out during the strongest UV period (such as 10am to 4pm), to achieve the best sun protection effect.