Cloudy weather ultraviolet ray

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

According to the ultraviolet radiation (watt/square meter), the monitoring data are divided into 10 files, and the average ultraviolet intensity monitored every day 10 ~ 14 hours according to the unified regulations of China Meteorological Bureau is taken as the ultraviolet intensity value of the day. According to the monitoring data and weather forecast, the forecaster predicted five different levels of ultraviolet intensity.

1, the ultraviolet index value is 0 to 2, which usually appears in cloudy or rainy days. At this time, the ultraviolet radiation intensity is the weakest, and the forecast level is 1 level. This amount has little effect on the human body. Just wear a sun hat when going out.

2. Cloudy weather, with an ultraviolet index value of 3 to 4. At this time, the intensity of ultraviolet radiation is weak, and the forecast level is level 2, which may have relatively little impact on human body. When going out, in addition to wearing a sun hat, you need to prepare sunglasses and apply sunscreen on your body to prevent your skin from being damaged by solar radiation.

3. The ultraviolet index value is 5 to 6, the ultraviolet radiation intensity is moderate, and the corresponding ultraviolet forecast level is Grade III, which has moderate damage to human skin. You must walk in the shade when you go out.

4. When the value is 7 to 9, the ultraviolet radiation intensity is strong, and the ultraviolet forecast level should be 4, which all appear in sunny days. At this time, it may have a great impact on the human body, and corresponding protective measures need to be taken. It's best not to bask in the sun on the beach from 10 to 4 pm.

5. When the ultraviolet index value reaches or exceeds 10, the ultraviolet radiation intensity is very strong, and the ultraviolet level is 5. Wan Li is generally a cloudless sunny day in Wan Li, especially in midsummer, which has the greatest impact on human body. Therefore, we must take protective measures and try to avoid outdoor activities.

Ultraviolet penetration:

Ultraviolet rays have poor penetration. Only a small part of ultraviolet rays can penetrate the glass. Ordinary glass can block more than 90% of ultraviolet rays with wavelength less than 300nm, but can let more than 90% of ultraviolet rays with wavelength greater than 350nm pass through. For the ultraviolet with the wavelength of 350 ~ 350 ~ 300nm, the blocking effect is between 10% ~ 90%.

The penetration of ultraviolet rays in liquid can decrease with the increase of liquid depth, and the impurities in water have a greater influence on the penetration. Dissolved salt, sugar and various organic substances will reduce the penetration of ultraviolet rays.

Penetration to solid substances, some objects that can be penetrated by visible light, such as glass, window paper, PVC film, dust, etc., cannot be penetrated by ultraviolet rays. It can block the penetration of ultraviolet rays and affect its sterilization effect.

Refer to the above content: Baidu Encyclopedia-Ultraviolet Index

Refer to the above contents: China Meteorological News Agency-Hunan Lianqing Sunshine Dazzling Expert Interprets Ultraviolet Monitoring and Forecasting.