Ever more frequently, dust storms envelop parts of northern China and Inner Mongolia, reducing visibility in cities like Beijing and threatening the health of millions of people. Such storms have become an increasingly common phenomenon for the region, as China’s deserts expand by gobbling up roughly 1,300 square miles a year. A half-century ago, such storms happened every seven or eight years; now they are an annual occurrence.
The storms typically happen in the spring, as strong winds send soil and sand from the Gobi Desert over northern China and even the Korean Peninsula.
Experts say the rapid urbanization of northern China, deforestation and climate change are all contributing to the problem. The government has spent huge amounts of money to plant trees to stop the creeping desertification, but some experts have questioned whether it has been effective enough in doing so.
Sand and dust storms start when hot air over the desert destabilizes the lower atmosphere, whipping up strong winds that send huge amounts of sand hundreds or even thousands of kilometers. The storms have been linked not only to respiratory illnesses but also to lethal epidemics because of the spread of potentially harmful bacteria, viruses and fungal spores.
The problem is exacerbated by high wintertime smog, which is caused by coal-burning power plants, factories and vehicle emissions.
 Lyu et al: Deposited atmospheric dust as influenced by anthropogenic emissions in northern China in Environmental Monitoring and Assessment - 2017