What is smog? How is it formed? What's the harm?
Haze is a combination of fog and haze. Due to the deterioration of air quality, haze weather phenomena have increased and the hazards have worsened. Many areas in China incorporate the haze weather phenomenon into fog as a disastrous weather warning and forecast. Collectively referred to as "haze weather".
The components and causes of smog
1. Sulfur dioxide, nitrogen oxides and inhalable particulate matter are the main components of smog. The first two are gaseous pollutants, and the last Particulate matter is the main culprit that aggravates haze weather pollution. They combine with the fog, making the sky instantly gray. The English abbreviation of particulate matter is PM, and the current high-frequency vocabulary PM2.5 in the air refers to pollutant particles with a diameter less than 2.5 microns. The particles themselves are both a pollutant and a carrier of toxic substances such as heavy metals and polycyclic aromatic hydrocarbons.
2. Sources of toxic particulate matter in cities: The first is car exhaust. Large vehicles using diesel are "heavy offenders" of emitting fine particulate matter, including large buses, shuttle buses of various units, and large transport trucks. Although small cars using gasoline emit gaseous pollutants, such as nitrogen oxides, they can easily be converted into secondary particulate pollutants in foggy weather, aggravating smog.
Third, it is the waste gas produced by burning coal for heating in winter in the north.
Fourth, it is waste gas emitted from industrial production. For example, there are industrial kilns and boilers in the metallurgical and mechanical and electrical manufacturing industries, as well as a large amount of exhaust gases emitted by the combustion of kilns for auto repair painting and building materials production.
5. Dust generated by construction sites and road traffic.
Dangers of haze weather
1. Impact on the respiratory system. The composition of haze is very complex, including hundreds of atmospheric chemical particulate matter. Among them, the main ones harmful to health are aerosol particles with a diameter of less than 10 microns, such as mineral particles, sea salt, sulfates, nitrates, organic aerosol particles, fuel and automobile exhaust, etc., which can directly enter and adhere to the human respiratory tract and alveoli. middle. In particular, submicron particles will be deposited in the upper and lower respiratory tracts and alveoli respectively, causing illnesses such as acute rhinitis and acute bronchitis. For patients with chronic respiratory diseases such as bronchial asthma, chronic bronchitis, obstructive emphysema and chronic obstructive pulmonary disease, haze weather can cause acute attacks or exacerbations of the disease. If you stay in this environment for a long time, it can also induce lung cancer.
2. Impact on the cardiovascular system. There are many pollutants in the air and low air pressure in haze weather, which can easily induce acute attacks of cardiovascular diseases. For example, when there is heavy fog, the water vapor content is very high. If people are active and exercising outdoors, the body's sweat is not easily discharged, causing chest tightness and increased blood pressure.
3. Haze weather can also lead to the weakening of ultraviolet rays near the ground, which can increase the activity of infectious germs in the air and increase the number of infectious diseases.
4. Due to the reduction of sunshine in foggy days, children are not exposed to enough ultraviolet rays, and the production of vitamin D in the body is insufficient, and the absorption of calcium is greatly reduced. In severe cases, it can cause rickets in infants and slowed growth in children.
5. Impact on mental health. Due to the weak light and low air pressure caused by gloomy and hazy weather, it is easy for people to feel lazy, depressed and pessimistic, and even lose control when encountering unpleasant things.
6. Affect traffic safety. When haze weather occurs, visibility is low and air quality is poor, which can easily cause traffic jams and traffic accidents.