Where does the dust in Beijing come from?

Sandstorms in Beijing mainly come from Alashan League, Bayannur League, Wulanchabu League, Xilin Gol League, northern Hebei and Loess Plateau in Inner Mongolia. There are also three routes, from Zhu Rihe in Inner Mongolia, Heihe in Hebei and eastern Shanxi to Beijing. Because sandstorms often move and settle, if sandstorms occur in other places and do not intensify during the movement, then there will only be floating dust weather in Beijing. But if there is a sandstorm in Beijing, it means that the sandstorm comes from the surrounding areas of Beijing, or even from the local area.