Automobile exhaust pollutants mainl

Automobile exhaust pollutants mainly include carbon monoxide, hydrocarbons, nitrogen oxides, sulfur dioxide, dust particles (some heavy metal compounds, lead compounds, black smoke and oil mist), odor (formaldehyde, etc.). According to statistics, about 3000 kg of carbon monoxide, 200 - 400 kg of hydrocarbons and 50 - 150 kg of nitrogen oxides are discharged from every thousand cars every day; 90% of the total air pollutants are discharged from mobile sources such as cars in Los Angeles, USA. Automobile exhaust is the main culprit of air pollution.
The main hazard of automobile exhaust is the formation of photochemical smog. Hydrocarbons and nitrogen oxides in automobile exhaust react chemically under the action of sunlight to produce ozone, which combines with other components of the atmosphere to form photochemical smog. Its harm to health is mainly manifested in irritating eyes, causing red eye disease, irritating nose, throat, trachea and lung, causing chronic respiratory diseases. Photochemical smog can cause trees to die and crop yields to be greatly reduced; it can reduce the visibility of the atmosphere and hinder traffic.
Carbon monoxide in automobile exhaust has the highest content. It can enter alveoli through respiratory tract, be absorbed by blood, combine with hemoglobin, form carboxyhemoglobin, reduce the oxygen carrying capacity of blood, weaken the oxygen supply of blood to human tissues, lead to tissue hypoxia, and cause symptoms such as headache, and death of severe asphyxia.
The content of nitrogen oxides in automobile exhaust is less, but its toxicity is very high. Its toxicity is three times that of sulfur oxides. Nitrogen oxides can form nitrite and nitric acid when they enter the alveoli, which can stimulate the lung tissue severely, increase the permeability of pulmonary capillaries, and finally cause emphysema. Nitrite binds with hemoglobin to form methemoglobin, which causes tissue hypoxia.
There are more than 200 hydrocarbons in automobile exhaust. When C2H4 concentration in the atmosphere reaches 0.5 ppm (1/100,000), some plants can develop abnormally. 32 kinds of PAHs were also found in automobile exhaust, including carcinogens such as 3,4-benzopyrene. When the concentration of benzopyrene in air reaches 0.012ug/m3, the number of lung cancer in residents will increase significantly. The closer to the highway, the greater the traffic on the highway, the higher the mortality rate of lung cancer.
Sulfur dioxide and suspended particulate matter in automobile exhaust will increase the incidence of chronic respiratory diseases and damage lung function. When the sulfur dioxide content in the atmosphere is too high, acid rain will be formed with precipitation.
Lead compounds in automobile exhaust can enter the blood with breathing, and quickly accumulate in human bones and teeth. They interfere with the synthesis of heme, invade red blood cells, cause anemia, damage the nervous system, damage brain cells in serious cases, and cause brain damage. When the concentration of lead in children's blood reaches 0.6-0.8 ppm, it will affect children's growth and intellectual development, and even cause dementia symptoms. Lead can also enter the placenta through the mother, endangering the fetus.