The higher the UV index in the weather forecast, the greater the damage to the skin.

The higher the UV index in the weather forecast, the greater the damage to the skin.

The monitoring data is divided into 10 levels according to the amount of ultraviolet radiation (watts/square meter). According to the unified regulations of the China Meteorological Administration, the average ultraviolet intensity monitored from 10:00 to 14:00 every day is the ultraviolet intensity value of the day. Forecasters make five different levels of UV intensity forecasts based on monitoring data and weather forecasts.

1. The ultraviolet index value is 0 to 2. It usually occurs on cloudy or rainy days. At this time, the intensity of ultraviolet radiation is the weakest and the forecast level is level one. This amount has basically no impact on the human body. When going out, Just wear a sun hat.

2. In cloudy weather, the UV index value is 3 to 4. At this time, the intensity of UV radiation is weak, the forecast level is Level 2, and the possible impact on the human body is also relatively small. Wear a sun hat when going out. In addition, you need to prepare sunglasses and apply sunscreen on your body to prevent your skin from being harmed by solar radiation.

3. The ultraviolet index value is 5 to 6. The intensity of ultraviolet radiation is medium, and the corresponding ultraviolet forecast level is level three. It has a moderately harmful effect on human skin. You must walk in the shade when going out.

4. When the value is 7 to 9, the intensity of ultraviolet radiation is strong, and the ultraviolet forecast level should be level four. They all appear on sunny days. At this time, the possible impact on the human body is relatively large, and corresponding measures need to be taken. As a protective measure, it is best not to bask in the sun on the beach between 10 a.m. and 4 p.m.

5. When the ultraviolet index value reaches or exceeds 10, the intensity of ultraviolet radiation is very strong at this time, and the ultraviolet level is level five. It is usually a cloudless sunny day, especially in midsummer, which has the greatest impact on the human body. If possible, protective measures must be taken and going out should be avoided as much as possible.

The penetrating power of ultraviolet rays:

The penetrating power of ultraviolet rays is poor. Only a small portion of UV rays can penetrate glass. Ordinary glass can block more than 90% of ultraviolet rays with wavelengths less than 300nm, but allows more than 90% of ultraviolet rays with wavelengths greater than 350nm to pass through. For ultraviolet rays with wavelengths between 350 and 300nm, the blocking effect is between 10% and 90%.

The penetrating power of ultraviolet rays in liquids can decrease as the depth of the liquid increases. Impurities in the water have a greater impact on the penetrating power. Dissolved salts, sugars and various organic matter can Reduce the penetration of ultraviolet rays.

Penetration of solid materials. Some objects that can transmit visible light cannot transmit ultraviolet rays, such as glass, window paper, polyvinyl chloride film, dust, etc., which can block the transmission of ultraviolet rays. , and affect its bactericidal effect.

Reference for the above content: Baidu Encyclopedia - Ultraviolet Index

Reference for the above content: China Meteorological News Agency - Hunan Lianqing Sun Dazzling Expert Interpretation of Ultraviolet Monitoring Forecast