1? Influence of air pollution on respiratory system health Air pollutants invade human body through respiratory tract, and harmful gases and tiny particles can reach the inside of lungs. If you are exposed to harmful gases and particulate pollutants for a long time, it will reduce the lung function, weaken or destroy the defense function of the respiratory tract itself, lead to chronic infection and inflammation, and finally lead to pathological changes of the respiratory system, which often manifests as chronic obstructive pulmonary diseases, such as chronic bronchitis, emphysema, bronchial asthma and so on. , eventually developed into pulmonary heart disease, and finally died of respiratory and circulatory failure.
Among the harmful gases, sulfur dioxide has a strong stimulating effect on human conjunctiva and upper respiratory mucosa, which can damage respiratory organs and lead to rhinitis, bronchitis, bronchial asthma, pneumonia and even pulmonary edema. Short-term exposure to sulfur dioxide concentration is 0? 5 mg/m3 air will increase the mortality rate of elderly or chronic patients; The concentration is higher than 0? 25 mg/m3 can aggravate the condition of patients with respiratory diseases; Long-term exposure concentration is 0? Respiratory diseases increased in people with 1 mg/m3 air. Sulfur dioxide and its secondary pollutants sulfurous acid and sulfuric acid can also corrode respiratory tissues, causing inflammation and necrosis. According to research, sulfur dioxide can also promote the carcinogenesis of benzo (a) pyrene in the air.
Nitrogen oxides in the atmosphere are mainly nitric oxide and nitrogen dioxide. Both chemical production and automobile exhaust will produce nitric oxide and nitrogen dioxide. Nitric oxide is not irritating, but it can be transformed into nitrite, causing methemoglobinemia, destroying the oxygen carrying capacity of blood, leading to tissue hypoxia and central nervous system damage. Nitrogen dioxide is highly irritating and corrosive, which can lead to pulmonary congestion and pulmonary edema.
Nitrogen oxides and hydrocarbons can undergo photochemical reactions under the irradiation of ultraviolet rays from the sun, resulting in secondary pollutants-photochemical smog. The main components are ozone, formaldehyde, acrolein, peroxyacetyl nitrate, etc. These substances are also called photochemical oxidants because of their strong oxidation. These secondary pollutants are irritating, which can cause irritation to respiratory tract, lungs and eyes, and can induce allergic diseases such as allergic rhinitis and bronchial asthma.
Dust particles in the atmosphere can be suspended in the air for a long time. The composition of particulate matter in the air varies from source to source, including metal, asbestos, cement and organic matter. Dust particles have strong adsorption capacity and can adsorb many pollutants in the air, including chemical pollutants and bacteria and other pathogens. Dust that adsorbs sulfur dioxide is usually an allergen that causes asthma attacks. Floating dust and large dust in the production environment often lead to pneumoconiosis.
2? The relationship between air pollution and cancer There are many carcinogens in air pollutants. According to animal experiments and epidemiological investigation, there are more than 30 kinds of air pollutants with carcinogenic effects. Such as polycyclic aromatic hydrocarbons, nitro polycyclic aromatic hydrocarbons and aromatic amines. It is often produced by pyrolysis of organic substances such as automobile exhaust, factory exhaust, smoke and dust, coal tar and asphalt, and its typical representatives are 3,4? Benzopyrene is a worldwide recognized carcinogen, which is closely related to the occurrence of lung cancer, skin cancer, gastric cancer, esophageal cancer and breast cancer. According to American research, 3,4? The concentration of benzopyrene increases by 0 per cubic meter? 00 1 μ g, lung cancer mortality will increase by 5%. If it is combined with carcinogens such as nickel, cadmium, chromium and arsenic in air particles, it will increase its carcinogenicity. These carcinogens often have high concentrations in heavily polluted air and are closely related to the increase of lung cancer among local residents.
3? Effects of Air Pollution on the Health of Nervous System and Cardiovascular System Air pollutants not only enter the human body through respiratory tract, but also enter the blood, causing toxic effects on other parts of the human body and damaging important organs of the whole body such as nervous system, cardiovascular system and skeletal system. Carbon monoxide is a gas pollutant produced by incomplete combustion of fossil fuels such as coal and oil, and cigarettes also contain a lot of carbon monoxide. Carbon monoxide is not stimulated when inhaled through the respiratory tract, so it is not easy to be detected. After carbon monoxide enters the human body, it quickly combines with hemoglobin in red blood cells to form carboxyhemoglobin, which reduces the oxygen carrying capacity of hemoglobin and eventually leads to tissue hypoxia. Because the tissues of nervous system and cardiovascular system are particularly sensitive to hypoxia, it is easy to cause dysfunction of nervous system and cardiovascular system. Long-term exposure to air with excessive carbon monoxide concentration will lead to chronic organic damage of nervous system and cardiovascular system. In addition, if the concentration of carbon dioxide in the air is too high, it will also lead to tissue hypoxia, shortness of breath, fatigue, headache, dizziness, convulsions and other symptoms. Formaldehyde in the air, lead, arsenic and mercury in floating dust all have toxic effects on nerve tissue.
4? The influence of air pollution on immune system: airborne particulate pollutants in the air accumulate in the lungs after inhalation, which first affects the local immune function and reduces the antibacterial and antiviral ability; Particulate pollutants can also reduce the ciliary movement ability of respiratory tract, making it difficult to remove foreign bodies attached to the surface of respiratory tract, thus leading to the decline of body resistance; Particulate pollutants have obvious toxic effects on immune macrophages in lung tissue, reducing the phagocytosis of macrophages, thus reducing the immune function of lung.
Gaseous pollutants in the atmosphere, such as sulfur dioxide and nitrogen oxides, will reduce the human body's ability to remove bacteria and viruses. Nitrogen dioxide can also inhibit the production of interferon by macrophages, so that the body's resistance to viruses is reduced. Under the action of long-term low-concentration gaseous pollutants, the systemic immune function will also change obviously. Generally, the immune function is excessively enhanced in the early stage, and immune diseases appear, while cellular immunity and humoral immunity decrease in the later stage.
Air pollution will also have adverse effects on the climate, such as reducing visibility and solar radiation (according to the data, the intensity of solar radiation and ultraviolet radiation in cities is lower than that in rural areas 10%-30% and 10%-25% respectively), leading to an increase in the incidence of rickets in cities.