Sandstorm or smog, which is more harmful?

At the same concentration (gravimetric method), fine particles in the air are more harmful than coarse particles. The average particle size in the air during smog is much smaller than that during sandstorm, so at the same concentration (this premise is crucial! ) Haze is much more harmful than sandstorm.

The main components of sandstorm are soil and yellow sand. Dust particles in soil push up PM 10. Other effects are not significant. There is a great difference between fog and haze, but in big cities, the main causes of haze weather are automobile exhaust, nitrogen oxides, PM2.5 and industrial waste gas. These pollutants include sulfur dioxide, nitrogen dioxide, carbon monoxide, ozone, PM2.5 and nitrogen oxides. It affects almost all indicators.

Dust weather doesn't mean it's harmless to human body. Generally speaking, it will have an impact on the respiratory system, especially on asthma patients, but this impact is easy to protect (wearing a mask). At the same time, the solid particles in the dusty weather can adsorb the organic matter in the atmosphere, and because most of the particles will not go deep into the lungs, the particles with aerodynamic diameter greater than 2.5 can remove the organic matter. Under the same smog weather, there is no removal effect of particulate matter on organic pollutants, of course, the harm will be greater, but this harm is often chronic and will not be reflected in a short time.

PM2.5 in smog is called fine particles, which refers to aerodynamic classified pollutants smaller than 2.5 microns. This kind of particulate matter is different from inhalable particulate matter Pm 10 and cannot be stopped in human respiratory tract. Nose hair and tracheal cilia can not be filtered, but directly enter alveoli, participate in pulmonary blood exchange and enter blood circulation. The research results of the United Nations and WHO show that PM2.5 can affect people's whole body through the blood-brain barrier. Therefore, high-intensity smog is particularly harmful to patients with cardiovascular and cerebrovascular diseases.