Why do residents in southern Xinjiang wear masks to travel recently?

Affected by the invasion of cold air, dusty weather occurred in Kashgar, Aksu and Bayinguoleng Mongolian Autonomous Prefecture in Xinjiang. Except Tashkurgan Tajik Autonomous County, the rain turned to snow in Kashgar, and dusty weather occurred in/kloc-0 counties and cities such as Kashgar, Shufu, Shule, Yengisha, Zepu, shache county and Yecheng. ?

Kashi Meteorological Observatory issued forecast and early warning information through multiple channels to provide accurate and timely forecast services for towns and villages, reminding the general public that the air quality in sandstorm weather is poor, and patients with respiratory diseases and sensitive person should reduce outdoor activities. The picture shows the East Lake Park in Kashgar City covered with floating dust.