When did the foggy weather in Beijing start? Will it happen every year after that?

Not every year, but it has become particularly serious in recent years.

Beijing is located in the north, with dry climate and close to the desert. Haze disasters are frequent in history, and the earliest records can be traced back to the Yuan Dynasty. According to Yuan Shi, 1329, there was no snow in March of the lunar calendar, and there was no rain in the spring of the previous year, which led to "rainy soil and haze". There are many related records in Ming Dynasty.

148 1 year, due to insufficient rainfall, "the wind blew for several days, and dust and haze enveloped the air."

1485, the drought caused hungry people near Beijing to flood into Beijing for food, and strong winds often blew in the city, which was called "wind haze" in history books.

1493, "Rain Haze in Beijing",

1497 It didn't snow in Beijing last winter, but it was windy and cloudy this spring.

1498, "In April, Dinghai, the capital was foggy for several days." .

1504, in Tongzhou district, "Spring and February, with constant wind and frost, covered the sky".

1506, Tongzhou City is foggy in October.

15 10 Beijing has been plagued by wind and haze since this spring.

15 16, Haidian District, "It doesn't snow in winter, but it's windy and foggy in spring".

1548, "It's foggy in Beijing in the first month" ...

Similar records are too numerous to mention. In short, the great haze will visit Beijing once every few years.

Before the Yuan Dynasty, Beijing was a small city. With the continuous expansion of the city, the number of buildings increases, the speed of air flow decreases, and the probability of smog increases accordingly. The end of the Ming Dynasty coincided with the Little Ice Age, and the climate in the north became colder and the precipitation decreased, which was conducive to the formation of haze weather.

Reducing smog depends on science, starting with restraining human behavior, doing a good job in greening, and paying attention to energy conservation and emission reduction.