Do you need sunscreen on cloudy days?
Among ultraviolet rays, UVC is very weak in the early stage and is almost completely absorbed by the atmosphere. UVB can penetrate the atmosphere, easily blocked by glass, and partially blocked by thick clouds in rainy days. UVA has the strongest penetration ability, accounting for 95% of the surface ultraviolet rays. Almost all UVA ultraviolet rays can penetrate the clouds, and UVA can reach the skin even if the clouds are thick in rainy days.
Unless it is a dark and big rain cloud, and the dark cloud is crushing the city to destroy it, the ultraviolet intensity will be greatly weakened. Sometimes, when the weather is cloudy or sunny, strong winds may blow away dark clouds and expose people to ultraviolet radiation.
In addition, when it rains in Chu Qing, the intensity of ultraviolet radiation is often stronger. This is because in continuous sunny days, some dust and particles will accumulate in the air, which will be suspended in the air to form a "protective film" and reflect some ultraviolet rays. After the rain clears, the "protective film" is washed away by the rain, and the intensity of ultraviolet radiation will be higher.
The amount of sunscreen and the best sunscreen;
The standard dosage of sunscreen is 2 mg/cm2, about 0.6 g-0.8 g at a time. It's a dose the size of a coin, not too strong or too much. This is unnecessary. Just apply evenly when applying, don't pat. In addition, foods rich in vitamins also help. Such as lemons, nuts and kiwis.
There are tomatoes, recognized as the best sunscreen food, rich in antioxidant lycopene. Daily intake of 16 mg of lycopene can reduce the risk of sunburn by 40%, and eating carrots will be more effective. Beta carotene can effectively block ultraviolet rays. Sun protection is a key part of skin care, which needs to be done well in daily life, even in rainy days. Sun protection should be based on hard sun protection, supplemented by sunscreen. When choosing sunscreen, you don't need to pursue too high a value, just choose the one that suits you.
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