Water pollution is not strictly defined and fixed standards. Water quality can be required: ① to maintain the natural state; ② meet the requirements of raw drinking water; ③ for fish survival and breeding; ④ suitable for agricultural irrigation; ⑤ suitable for swimming and other water sports activities; ⑥ consistent with a variety of industrial water raw water The requirements; ⑦ does not show the status of dirty. For the water quality of these bodies, many countries have specific requirements. China promulgated the "Surface Water Environmental Quality Standard" as a basis for controlling water pollution. Water pollution sources come mainly from domestic sewage, industrial wastewater, agricultural wastewater and precipitation runoff caused by groundwater; groundwater bodies in the coastal areas, as well as sea water intrusion. Water pollutants are: ① pathogens, such as germs, viruses and parasite eggs; ② from animals and plants of organic matter, such as animal and plant feces, animal and plant debris, the body's components, and their bacteria in the water The role of consumption of dissolved oxygen; ③ plant nutrients, mainly nitrogen and phosphorus compounds, will make the waters of emberiza eutrophication; ④ toxic and hazardous chemicals, such as chlorine pesticides (DDT, BHC, etc.) , Heavy metal salts, radioactive substances, etc .; ⑤ others, such as oil, acid, alkali, warm water, suspended solids, etc. (see wastewater quality). Some of the pollutants entering the water body can be degraded under the action of microorganisms, such as organic matter in domestic sewage, most of which are converted into inorganic substances such as bicarbonate, nitrate and sulfate under the action of bacteria. Some of them can not be degraded, Inorganic pollutants. Degradation of water bodies, dilution and the surrounding environment, such as the role of the exchange of oxygen (from the air in the air to absorb oxygen), making the water quality of con***inated water tends to recover ability, known as self-purification capabilities. When the amount of pollutants does not exceed the self-cleaning capacity, the water body to maintain a normal state; when more than self-purification capacity, the water will show unclean state.Water pollution control measures, in addition to strengthening the management of pollution sources to reduce the amount of waste water and pollution, the government should develop and promulgate laws and regulations to control the discharge of waste water, such as the Chinese government enacted and promulgated the "******* water pollution Prevention Law "," Industrial "three wastes" emission standards "and other laws and regulations. Town should be the construction of a complete drainage system and wastewater treatment plant, and the development and implementation of management system. Industrial layout and process to consider the environmental requirements. Production wastewater must be treated before leaving the factory (see industrial waste water treatment) and wastewater reuse, especially the establishment of wastewater irrigation system, is an effective way to prevent wastewater from polluting water.

The quality of drinking water directly affects human health. The towns should build a sound water supply system to supply drinking water (see water quality) to residents in line with the "drinking water health standards." The strict protection of water sources, the perfect treatment of raw water (see the water treatment plant) and the well-maintained water supply network (see the water supply network conservation) is to ensure that water quality is good and effective measures.

The air quality requirements are different for different ranges. Open areas should maintain the natural quality of the air. Urban air should have a higher quality. The local air pollution sources, especially the air quality requirements inside the workshop may be lower, but should not endanger the health of staff or residents. China promulgated the "Atmospheric Environmental Quality Standards" and "Industrial Enterprises Design Health Standards" and other regulations in order to control air pollution. Air pollution is localized, such as indoor pollution, individual chimney pollution; regional, such as urban traffic pollution. Due to the flow of air, localized pollution can become regional and even become global after the expansion of regional pollution.Air pollution can result in increased dustfall, reduced visibility, poor tree growth, and even wilting. However, the most important hazard is the impact on human health, ranging from illness and death to death. The 1952 London smog caused by atmospheric sulfur pollution killed 4,000. Acid rain caused by atmospheric pollution, plant damage, corrosion of buildings, victims of a wider area, is causing serious concern.Sources of atmospheric pollution are mainly the combustion of fossil fuels (coal, oil, gas). Pollutants emitted by some industrial processes also pollute the atmosphere, but generally only affect nearby areas. Gale and vehicles cause dust and sometimes air pollution (see Traffic Engineering). Volcanic eruptions are another source of pollution.Air pollutants are: ① dust. Collectively, all non-gaseous pollutants, also known as particulate matter, mainly dust and smoke. Dust generally comes from topsoil. Smoke is a product of incomplete combustion, the main body is carbon particles, adsorption of other impurities. The hazards of soot are the reduction of the general quality and visibility of the atmosphere. However, the lead particles formed during the combustion of leaded petrol and dust and smoke from industrial processes can be directly pathogenic. ② carbon monoxide. Incomplete fuel combustion products, is colorless, odorless, toxic gas, slightly lighter than air, diffuse faster. In cities with heavy traffic, carbon monoxide in the surface air comes from cars at concentrations of up to 10-100ppm, while living in air at 10ppm for 8 hours may affect people's mental activity. ③ sulfur dioxide. Sulfur fossil fuel combustion products. In China mainly from coal-fired boilers and stoves. Corrosion artifacts to stimulate the respiratory tract. Chimney to high altitude diffusion, often oxidation of sulfur trioxide, the formation of sulfuric acid or sulfate, into the raindrops, there will be pH below 5 acid rain. ④ nitrogen oxides. Nitrogen oxides such as nitric oxide and nitrogen dioxide are the products of fuel combustion at high temperatures. Nitrogen in the atmosphere is oxidized to nitric oxide at high temperatures, which in turn is converted to nitrogen dioxide. Nitrogen oxides are reactants in atmospheric photochemical reactions that directly affect health at high concentrations. ⑤ hydrocarbons. Gas is generally incomplete combustion of the product. Lower concentrations are not directly hazardous to health, but are reactants in atmospheric photochemical reactions. ⑥ photochemical reaction oxidant. The reaction products of nitrogen oxides and hydrocarbons under sunlight, ozone, nitric oxide, nitrogen dioxide, a mixture of peroxyacetyl nitrate (PAN), formaldehyde, acrolein, nitric acid and the like are secondary con***inants . Their pollution parameters are total oxidants. The photochemical reaction with the oxidant fumes called photochemical smog, has caused serious harm, the comprehensive impact on health is still under study. Concentrations of about 0.1 ppm irritate the mask and respiratory tract. In addition, nitric acid may be another factor causing acid rain. ⑦ carbon dioxide. Under normal conditions, the atmospheric carbon dioxide is generally in equilibrium due to photosynthesis and respiration of the plants. However, the increasing amount of fossil fuel burned increases the concentration of carbon dioxide in the atmosphere. Because of the greenhouse effect of carbon dioxide, some people think that it is possible to cause an increase in the average temperature of the earth's atmosphere, melting polar ice and causing serious environmental problems.Air pollution control measures, afforestation and urban greening contribute to the improvement of air quality, and the creation of windbreaks can prevent the spread of dust. However, prevention and treatment of air pollution mainly lies in: ① energy innovation. When possible, use uncon***inated energy sources (solar, wind, geothermal energy, electricity and steam), or low-pollution sources of energy (gas and oil) to replace coal. The distribution of coal should also take into account pollution control, low-sulfur coal should be allocated to the stove and small combustion equipment, the more easy to adopt pollution prevention measures of large-scale combustion equipment should be allocated high sulfur coal. High sulfur fuel available desulfurization technology to reduce sulfur content. Gas desulfurization technology see city gas purification. ② equipment and operation of innovation. Innovative dust removal equipment will help to reduce the amount of soot, improve the efficiency of combustion equipment can reduce the pollution of carbon monoxide and hydrocarbons. Flame temperature control, can reduce nitrogen oxidation and carbon dioxide decomposition. The prevention and control of automobile exhaust pollution mainly relies on the reforming of the combustion system of automobiles. A great deal of research has been carried out and the reform is still under way. Lead in the car exhaust gas only need to add lead gasoline to eliminate. ③ exhaust gas treatment. Is the means of prevention and control of air pollution. Smoke in the flue gas can be filtered, washed, centrifuged, electrostatic precipitation, sonic deposition and other methods and air separation. Removal of sulfur dioxide in flue gas there are a variety of ways: the limestone powder blowing into the combustion chamber, and sulfur dioxide synthesis of ash; with alkaline substances absorb or absorb sulfur dioxide, and then use; in the role of catalyst combustion flue gas, so that sulfur dioxide into tris Sulfur dioxide, flue gas cooling condensate combined with sulfuric acid. Nitrogen oxides in flue gases can also be chemically removed.

Solid waste disposal methods are buried, incineration or processing and utilization. Incineration can also be seen as a treatment. Because the ash is still to be disposed of. The collection and storage of solid waste, especially rubbish, will cost less and will not affect sanitation. ① Agricultural solid wastes (straw, livestock excrement) are generally organic matter and have historically been used as feedstuffs, fuels and fertilizers in rural China. Since 2010, biogas fermentation has been used to treat agricultural solid waste. Biogas is a clean, convenient fuel and the residue is a good fertilizer. When the amount of industrial solid waste is small, it is often treated as garbage. Considerable use of quantities (see Industrial Waste and its Applications); Buried or incinerated when not in use. Toxic and hazardous waste to be buried before harmless treatment, can not handle the seal buried. ③ urban garbage is a mixture of solid waste in the city. In China, kitchen residuals are traditionally collected separately from rubbish for pigs and fertilizer fields. Garbage disposal methods are mainly buried, a few incineration, but also for composting. Buried, including landfill, fill pit, change the wetlands for the venue and abandoned in the sea. Abandon the sea even if no adverse consequences, long-term consideration. In the past, landfill was similar to simple dumping and continued to pollute the environment and cause rodents. Requires daily dumping of rubbish covered with mud and compacted the same day, saying that health buried. Landfill greening, after 10 years or more time to build a house above. Landfill available sanitary burial law fake mountain, increase landfill volume, beautify the environment. Take waste materials recycling measures, you can reduce the amount of garbage.

Interfere with rest, study, life and work, and even affect the health of the sound, collectively referred to as noise. Noise consists of many pure tones. The sound pressure (p) of a pure tone (single frequency sound) is expressed in terms of sound pressure level (Lp) compared to the reference sound pressure (p0 is close to that of the average person, usually p0 = 2 × 10-5 Pa) (DB), its mathematical expression is Lp = 201g (p / p0). Determination of the strength of the noise is more complicated, not only to combine the frequency of pure tone, but also with the subjective feelings of people. There are many ways to measure, the general use of sound level, the unit also uses decibels. Sound level available sound level meter directly measured. Sound level increased 40 dB, sound pressure increased about a hundred times, greatly increased interference. Generally believed that less than 85 decibels will not affect hearing. Jet aircraft took off at 150 dB noise, making the ear drums hurt. 160 dB noise makes people deaf. Noise also affects the human central nervous system and cardiovascular system, leading to neurasthenia and cardiovascular disease. Noise also affects the speech and the use of the phone. Noise that can cause deafness also affects the use of certain instruments.Noise comes mainly from machinery (industrial noise) and transportation (traffic noise). Noise control is not the first noise equipment: or the reform process, such as change the riveting for welding; or change the machinery, such as using pile driver instead of pile driver. Followed by the reform of mechanical structure and materials, such as improving the accuracy of parts to reduce collision, with non-metallic materials instead of metal materials, transmission components with elastic components, the machine uses vibration isolation base or noise enclosures, exhaust muffler set, transport Shape using streamlined and so on. Again the correct operation, such as the proper use of lubricants, the proper use of speakers and other audio equipment. Building sound insulation barriers (such as walls and mounds) or multi-purpose sound absorbing and sound insulating materials on building surfaces, as well as rational urban planning are also effective measures (see Airport Environmental Protection).

Radioactive substances generated by ionizing radiation over a certain dose on the health of people. With a certain thickness of lead or concrete enclosed radioactive material, you can block this ionizing radiation. In nuclear power stations or industrial, medical and scientific research departments that use radioactive substances, they can be avoided as long as they are operated and managed in accordance with the regulations. Radioactive waste, whether gaseous, liquid or solid, should be stored below a certain level of ionizing radiation before being allowed to enter the environment. For ease of storage, often concentrated, concentrated exhaust gas and waste must be cured for disposal.

Excessive combustion, air pollution and changes in physical properties can change the ambient temperature and affect the natural, ecological balance locally, regionally or globally. Power plants and industrial cooling water are the most common water pollution sources. Cooling water directly discharged into rivers and lakes will raise the water temperature, speed up the metabolism of water organisms and reduce dissolved oxygen, thus affecting fisheries and destroying the natural balance. Circulating cooling water systems can be used to reduce cooling water discharges or cool down through cooling ponds before being discharged into natural waters.

Radio broadcasting, television and microwave technologies are rapidly gaining popularity. The power of radio frequency equipment has doubled so that the intensity of nearby electromagnetic radiation reaches a level that directly threatens human health.The means of protection of electromagnetic radiation is generally to place electromagnetic shielding devices around the radio frequency equipment or the protection object so that the electromagnetic radiation intensity within the protection range falls within the allowable range. Electromagnetic shielding devices are the main shield, shielding room, shielding clothing, helmet and goggles mask, shielding different objects, using different devices. In addition, comprehensive prevention and control measures should be taken, such as rationalizing the layout of electromagnetic pollution sources away from populated residential areas, improving electromagnetic equipment so as to reduce the electromagnetic radiation to the environment, enhancing the automation and remote control of electromagnetic equipment to reduce the workload of staff Exposure to high-intensity electromagnetic radiation opportunities.