Beijing is influenced by monsoon, with northwest wind prevailing in winter and southwest wind prevailing in summer. No matter what kind of wind, wind power is mostly beneficial to the diffusion of pollutants.

But relatively speaking, the northwest wind is more conducive to the diffusion of pollutants in Beijing. Topographically, Beijing is almost surrounded by mountains on three sides, and it belongs to a dustpan-shaped terrain. If the south wind blows, the south wind is like a broom, sweeping pollutants into the dustpan. If there is no strong northwest wind blowing out pollutants, dirty air can only gather in the dustpan. Therefore, the northwest wind has the strongest "lethality" to smog.

Moreover, the cold air originally came from the Arctic Ocean and was later strengthened by Siberia. Siberia is an undeveloped land with a small population, and cold air will not "pollute" the ground during its formation. Therefore, the northwest wind carries less pollution sources and is relatively pure. On the contrary, there are more human production and life and more pollution sources in the area where the southerly wind passes. Therefore, I suggest you choose Mike Runfei Oral Liquid, which is specially developed for the haze season.