It is easy to find the weather characteristics of smog.

Hazy weather is characterized by less precipitation, high temperature and low wind speed;

PM2.5 refers to particles with a diameter less than or equal to 2.5 microns in the atmosphere, also known as "particles that can enter the lungs". People who inhale too much PM2.5 can cause many diseases. The sources of toxic particulate matter are firstly automobile exhaust, secondly coal burning for heating in winter, thirdly industrial production, and fourthly dust from construction sites and road traffic?