There are many pollutants in smog, including particulate matter and nitrogen oxides including pm25.

Haze is a combination of fog and haze. Because of the deterioration of air quality, the phenomenon of smog weather has increased and the harm has become more serious. In many areas of China, the phenomenon of haze weather is combined with fog as an early warning and forecast of disastrous weather, which is collectively called "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 one is the chief culprit that aggravates smog weather pollution. Combined with fog, they make the sky suddenly gloomy. The English abbreviation of particulate matter is PM, but now the high-frequency vocabulary of air refers to pollutant particles with a diameter less than PM2.5 microns. The particles themselves are not only pollutants, but also heavy metals and polycyclic aromatic hydrocarbons.

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

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

Fourth, the waste gas emitted by industrial production, such as metallurgical, electromechanical industrial kilns and boilers, as well as a large number of waste gas emitted by automobile repair, painting, building materials production kiln combustion and so on.

Dust from construction sites and road traffic.

Haze weather hazard

1. Effects on 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. Especially submicron particles, will be deposited in the upper and lower respiratory tract and alveoli respectively. Can cause 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 can cause acute attacks or acute exacerbations. Staying in this environment for a long time will also induce lung cancer.

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

3. Smog weather will also weaken the surface ultraviolet rays, enhance the activity of infectious bacteria in the air and increase infectious diseases.

Fourth, in foggy days, due to the reduction of sunshine, children's ultraviolet radiation is insufficient, vitamin D production in the body is insufficient, and the absorption of calcium is greatly reduced, which will seriously cause rickets in infants and children and slow down their growth and development.

5. Affect mental health. The gloomy and foggy weather is prone to mental laziness, depression and pessimism due to weak light and low air pressure, and it is even easy to get out of control when something goes wrong.

6. Affect traffic safety. In foggy weather, the visual visibility is low and the air quality is poor, which is easy to cause traffic jams and traffic accidents.

Tmall us wechat reminds: remember to protect yourself when traveling in foggy days.