In recent years, "haze" weather has appeared frequently, seriously affecting people's lives. PM2.5 is the main cause of "haze" weather and contains a large amount of

(1) PM2.5 is the main cause of the formation of "haze". It is rich in toxic and harmful substances, stays in the atmosphere for a long time, and is transported over long distances. Air entering the lungs must pass through the nasal cavity, pharynx, larynx, trachea and bronchi. However, PM2.5 particles are so small that they are not easily blocked by the nose and other organs. They can directly enter the bronchi and alveoli, affecting the gas exchange in the lungs and causing diseases such as asthma. After entering the lungs, it can be quickly absorbed by the capillaries outside the alveoli and distributed throughout the body through blood circulation. It can be seen that PM2.5 mainly harms the human respiratory system.

(2) "Haze" weather causes great harm to human health. The main cause of "haze" is PM2.5. Therefore, the main measure to avoid the harm of this weather to human body is to reduce For inhalation of PM2.5, methods such as wearing a special mask (a mask with an activated carbon adsorption layer) and minimizing going out can be adopted.

(3) Haze weather is mainly caused by excessive PM2.5 in the air. PM2.5 refers to particulate matter in the air with a diameter less than or equal to 2.5 microns. These particles come from the burning of large amounts of fossil fuels. Therefore, PM2.5 needs to be reduced to slow down smog. Therefore, centralized heating in residential areas, emissions after waste treatment in factories, and restrictions on odd and even numbers for cars can all reduce smog.

So the answer is: (1) Breathe (2) Wear a special mask (a mask with an activated carbon adsorption layer) and minimize going out. (3) Centralized heating in residential areas, emissions after waste treatment in factories, and restrictions on odd and even numbers for cars can all reduce smog.