Air pollution mainly refers to the chemical pollution of the atmosphere. There are many kinds of chemical pollutants in the atmosphere, and dozens of them are seriously harmful to human body. Air pollution in China belongs to coal-burning pollution (see photo). The main pollutants are soot and sulfur dioxide, in addition, there are nitrogen oxides and carbon monoxide. These pollutants mainly enter the human body through the respiratory tract, and are directly transported from the blood to the whole body without detoxification of the liver. Therefore, the chemical pollution of the atmosphere is very harmful to human health. This kind of harm can be divided into three types: chronic poisoning, acute poisoning and carcinogenesis.

The concentration of chemical pollutants in the atmosphere of chronic poisoning is generally low, which mainly produces chronic toxic effects on human body. Scientific research shows that chemical pollution in urban air is an important cause of chronic bronchitis, emphysema and bronchial asthma. Acute Poisoning When the factory emits a lot of harmful gases and there is no wind and fog, the chemical pollutants in the atmosphere are not easy to disperse, which will cause acute poisoning. For example, in 196 1 year, three petrochemical enterprises in Niigata, Japan continuously discharged a large number of chemical pollutants such as sulfur dioxide, and windless weather caused asthma among local residents. Later, the local air pollution was controlled and the incidence of asthma decreased.

Carcinogenesis Among the chemical pollutants in the atmosphere, polycyclic aromatic hydrocarbons (such as 3,4-benzopyrene) and lead-containing compounds have carcinogenic effects, among which 3,4-benzopyrene has the strongest effect on lung cancer (see figure). The smoke produced by burning coal, cars and cigarettes contains a lot of 3,4-benzopyrene. Chemical pollutants in the atmosphere can also fall into water, soil and crops, and be absorbed and enriched by crops, thus endangering human health.

Air pollution also includes biological pollution and radioactive pollution. Biological pollutants in the atmosphere mainly include pathogenic bacteria, mold spores and pollen. Pathogens can make people suffer from infectious diseases such as tuberculosis, and mold spores and pollen can cause allergic reactions in some people. Radioactive pollutants in the atmosphere mainly come from radioactive wastes from the atomic energy industry and medical X-ray sources, which are easy to cause skin cancer and leukemia.

②. Water pollution and human health

After rivers, lakes and other water bodies are polluted (pictured), it will cause serious harm to human health, mainly in the following three aspects. First of all, drinking the organic matter in polluted water and edible sewage will make people poisoned and even die. For example, 1956, there were some patients with unknown etiology in Minamata Bay, Kumamoto Prefecture, Japan. The patient developed symptoms such as spasm, paralysis, dyskinesia, language and hearing disorders, and finally died of pain due to incurable treatment. People call this strange disease Minamata disease. Scientists later discovered that the disease was caused by local industrial wastewater containing mercury. Mercury is converted into methylmercury and enriched in fish, shrimp and shellfish. If people eat these fish, shrimp and shellfish for a long time, methylmercury will cause chronic methylmercury poisoning, mainly brain cell damage. Methylmercury in pregnant women can even make children stunted, mentally retarded and deformed limbs. Second, the water polluted by human and animal feces and domestic garbage can cause infectious diseases such as viral hepatitis and bacillary dysentery, as well as parasitic diseases such as schistosomiasis. Thirdly, some carcinogenic chemicals, such As arsenic (As), chromium (Cr) and aniline, can accumulate in suspended solids, sediments and aquatic organisms after polluting water bodies. Drinking such sewage for a long time is easy to induce cancer.

(3) Solid waste pollution and human health Solid waste refers to solid substances discarded by human beings in production and life, such as waste rocks from mining industry, industrial waste residue, discarded plastic products (as shown in the figure) and domestic garbage. It should be recognized that solid waste can only be used in a certain process or a certain aspect. In fact, it can often be used as a raw material for another production process. Therefore, solid waste is also called "misplaced raw materials". However, these "misplaced raw materials" often contain a variety of substances harmful to human health. If it is not used in time and piled up for a long time, it will pollute the ecological environment and cause harm to human health.

④ Noise pollution and human health.

Noise is harmful to people in many ways: first, it damages hearing. Working in strong noise for a long time will reduce hearing and even cause noise deafness. Second, interfere with sleep. When people's sleep is disturbed by noise, they can't eliminate fatigue and recover their physical strength. Third, induce a variety of diseases. Noise can make people nervous, lead to an increase in heart rate and blood pressure, and even induce gastrointestinal ulcers, endocrine system dysfunction and other diseases. Fourth, it affects mental health. Noise can make people fidget, unable to concentrate on study and work, and easily lead to work-related injuries and traffic accidents. Therefore, we should take various measures to prevent and control environmental pollution so that all living things, including human beings, can live in a beautiful ecological environment.

3. The influence of environmental pollution on biology, environmental pollution and "three effects"

Environmental pollution often has carcinogenic, mutagenic and teratogenic effects on humans or mammals, which are collectively called "three effects". The harm of "three effects" usually takes a long time to appear, and some harm will even affect future generations.

1. Carcinogenesis

Carcinogenesis is the function of guiding people or mammals to get cancer. As early as 1775, British doctor Porter found that chimney sweepers were prone to scrotal cancer, which he believed was related to frequent contact with soot. 19 15 years, Japanese scientists confirmed through experiments that coal tar can induce skin cancer. Among pollutants, substances that can induce cancer in humans or mammals are called carcinogens. Carcinogens can be divided into three categories: chemical carcinogens (such as nitrite, asbestos and dichloromethyl ether used in mosquito-repellent incense production), physical carcinogens (such as nuclear fusion of radium) and biological carcinogens (such as aflatoxin).

(2) Mutation Mutation is the function of inducing gene mutation, chromosome structure variation or chromosome number variation in humans or mammals. If the germ cells of human beings or mammals mutate, it can affect the pregnancy process and lead to infertility or early embryonic death. If human or mammalian somatic cells mutate, it will lead to cancer. Common mutagens are nitrosamines, formaldehyde, benzene and dichlorvos.

3. Teratogenesis refers to the effect of acting on pregnant mothers, interfering with the normal development of embryos and leading to congenital malformation of newborns or young mammals. In the early 1960s, some deformed newborns appeared in Western Europe and Japan. Scientists have found that pregnant women take a sedative called thalidomide within 30 to 50 days after pregnancy, which has teratogenic effect. At present, the teratogens confirmed are methylmercury and some viruses.