What is smog? How to form? What are the disadvantages?

Haze is a combination of fog and haze. Because of the deterioration of air quality, cloudy days have increased and the harm has increased. In many areas of our country, the smog weather phenomenon is combined with fog as an early warning and forecast of disastrous weather. Collectively referred to as "haze weather".

Composition and causes of smoke

1. Sulfur dioxide, nitrogen oxides and inhalable particles are the main components of smog. The first two are gaseous pollutants, and the last particulate matter is the chief culprit that aggravates smog weather pollution. They combine with fog and instantly turn the sky gray. The English abbreviation of particulate matter is PM, and now the high-frequency vocabulary of air PM2.5 refers to pollutant particles with a diameter less than 2.5 microns. This particle itself is not only a pollutant, but also a carrier of toxic substances such as heavy metals and polycyclic aromatic hydrocarbons.

Second, the source of toxic particles in cities: first, automobile exhaust. Large vehicles that use diesel are "recidivists" who emit fine particles, including buses, shuttle buses of various units and large transport trucks. Small cars that use gasoline emit gaseous pollutants, such as nitrogen oxides, which are easily converted into secondary particulate pollutants in foggy days, aggravating smog.

The third is the waste gas produced by burning coal for heating in winter in the north.

Fourth, it is the waste gas emitted by industrial production. For example, industrial kilns and boilers in metallurgy and electromechanical manufacturing industries, as well as a large amount of waste gas generated by the combustion of automobile repair and painting and building materials production kilns.

5. Dust generated by construction sites and road traffic.

Haze weather hazard

First, the impact on the respiratory system. The composition of smog is very complex, including hundreds of atmospheric chemical particles. Among them, aerosol particles smaller than 10 micron are harmful to health, such as mineral particles, sea salt, sulfate, nitrate, organic aerosol particles, fuel, automobile exhaust, etc., which can directly enter and adhere to human respiratory tract and alveoli. In particular, submicron particles will be deposited in the upper and lower respiratory tract and alveoli respectively, causing acute rhinitis and acute bronchitis. For patients with chronic respiratory diseases such as bronchial asthma, chronic bronchitis, obstructive emphysema, and chronic obstructive pulmonary disease, smog weather will make the condition acute or acute. Staying in this environment for a long time will also induce lung cancer.

Second, the impact on the cardiovascular system. There are many pollutants in the air in foggy days, and the air pressure is low, which is easy to induce acute attacks of cardiovascular diseases. For example, when the fog is heavy, the water vapor content is high. If people exercise outdoors, the sweat of human body is not easy to be discharged, which causes people to feel chest tightness and blood pressure to rise.

Third, the smog weather will also lead to the weakening of ultraviolet rays in the surface layer, which can enhance the activity of infectious bacteria in the air and increase infectious diseases.

Fourthly, due to the decrease of sunshine, insufficient ultraviolet radiation for children, insufficient production of vitamin D in the body and greatly reduced absorption of calcium in foggy days, rickets in infants and young children will be seriously caused, which will slow down the growth and development of children.

Fifth, it affects mental health. The gloomy and foggy weather is prone to mental laziness, depression and pessimism due to the weak light and low air pressure, and even it is easy to get out of control at the slightest sign of trouble.

Sixth, it affects traffic safety. In foggy weather, the visibility of the visual field is low and the air quality is poor, which is easy to cause traffic jams and traffic accidents.