What are the points above and below the middle two circles?

The weather forecast symbol has two circles side by side, with three points on the top and three points on the bottom, indicating (moderate-severe) smog.

Haze (mái), also known as haze (smog), dust, sulfuric acid, nitric acid, organic hydrocarbons and other particles in the air can also make the atmosphere turbid. The phenomenon that the horizontal visibility of the target is 1000 ~ 10000 meters is called light fog or mist.

When fog is formed, the atmospheric humidity should be saturated (if there are a large number of condensation nuclei, the relative humidity may not reach 100%, and saturation may occur). Because the light scattered by fog composed of liquid water or ice crystals has little to do with wavelength, the fog looks milky white or bluish white and gray.