The human environment generally refers to the environment of human life. The human environment is the external world with human as the center, that is, the synthesis of natural and artificially transformed natural factors on which human survival and development depend. (In 1972 United Nations Conference on the Human Environment ). [1] In the long development process of the earth for billions of years, the environment suitable for human survival has gradually formed, thus forming life. The living environment of human beings is very complex, including all the natural and social conditions that exist objectively and are related to human survival. world health organization The environment is defined as the overall state composed of various physical, chemical, biological and social factors at a specific time, which may directly or indirectly have a real or long-term effect on the living organism or human activities. The environment of human existence includes natural environment and living environment, and its composition and quality are closely related to health. The environment on which human beings live is generally composed of natural environment and social environment (artificial environment). The natural environment is the general term of the natural conditions and natural resources necessary for human life and production, that is, the sum of natural factors such as sunshine, temperature, climate, geomagnetism, air, water, rock, soil, animals and plants, microorganisms, and the stability of the crust. It is the material basis for human survival. According to its composition characteristics, it can be divided into Atmosphere , hydrosphere, soil lithosphere and biosphere. The social environment is an artificial environment created and established by human beings on the basis of the natural environment through long-term planned and purposeful development in order to continuously improve the material and spiritual living standards. Social environment is human material civilization and Spiritual civilization The sign of development is constantly changing with the development of economy, science and technology. The development of social environment is dominated and restricted by natural law, economic law and social development law. The quality of social environment has a great impact on human life, work and social progress. The human centered environment is the ultimate material source for human survival and development, and also bears human activity Various functions of waste generated. [1] ⑴ According to the formation of environment, it can be divided into natural environment and artificial environment. (The most commonly used classification method)
The natural environment and living environment that human beings rely on for survival are a complex composed of various environmental factors, and the human environment is ecology One kind of environment. Ecological environment includes human environment. According to the attributes of environmental factors, it can be divided into the following four categories. ① Physical factors: temperature, air humidity wind speed 、 thermal radiation And other meteorological conditions, which have a great impact on the heat balance of the human body. ambient noise It can affect human hearing and other physiological functions, and interfere with rest and sleep. Ultraviolet ray in solar radiation has the functions of sterilization, anti rickets, and enhancing immunity. microwave radiation It may have certain influence on cardiovascular system. In addition, human production activities Radioactive waste It can cause radioactive pollution to the environment and cause health hazards. ② Chemical factors: The content of many chemical components in the natural environment is suitable for human survival. But human production and living activities can atmosphere 、 water 、 soil The chemical composition changes within a certain range, resulting in a large amount of Chemical pollution Substances not only affect environmental quality, but also can enter the body through air, water, food and other environmental media, causing various harmful effects on human health. For example, irrigation of farmland with wastewater containing cadmium can significantly increase the content of cadmium in crops such as rice through bioaccumulation and biological amplification. If local residents eat rice with high cadmium content for a long time, a large amount of cadmium will accumulate in their bodies, leading to chronic poisoning. Human beings are exposed to many chemical environmental factors with complex components, among which the chemical pollutants that are widely distributed and seriously harmful to human health mainly include Sulfur oxide 、 nitrogen oxide 、 carbon monoxide , smoke, volatile hydrocarbons, heavy metal compounds Oxygen consuming organics 、 Polycyclic aromatic hydrocarbons , petroleum, phenol, cyanide, pesticide Halohydrocarbon 、 Radioactive material Etc. ③ Biological factors Biological factors mainly refer to bacteria, fungi Viruses 、 parasite And biological allergens (e.g Fungal spore , plant pollen Dust mite Etc.). If the microbial population in the environment changes or exists in the environment Biological pollution , which may affect human health. Historically, by Pathogenic Microbes Caused by cholera 、 plague Such infectious diseases once seriously threatened human life and health. Pollen, dust mites and their metabolites can become biological allergens and induce some allergic diseases. Some animals and plants that can produce toxins can cause health hazards after contacting human body in a certain way, such as snake venom bite, fugu poisoning, eating poisonous mushrooms by mistake, etc. ④ Social psychological factors Good socio-economic conditions, suitable working and living conditions, necessary social security, good lifestyle, etc. are conducive to human health; Social unrest, heavy economic burden, poor working and living conditions, smoking Alcoholism Such bad living habits will hinder the development of people's physical and mental health. Social factors and psychological factors are closely related, and their effects on health are often complementary. With the change of modern medical model and health concept, the impact of social psychological factors on human health has been increasingly valued. [1] ⑵ According to whether the environment has been affected by human activities, it can be divided into Primary environment and Secondary environment 。 Primary environment It refers to the environment that is naturally formed and is not or less affected by human factors. In the original environment, there are many factors beneficial to human health, such as clean air, water and soil with normal chemical composition, suitable solar radiation and meteorological conditions, and beautiful scenery, which are all beneficial to health. However, some original environments also have adverse effects on the body for various reasons, such as Biogeochemical disease It is because there are too many or too few elements in the water and soil in the original environment. After residents drink water and eat for a long time, there are too many or too few corresponding elements in their bodies. Finally, it causes specific diseases with obvious regional characteristics. The environment formed under the influence of human activities is called Secondary environment 。 In the process of transforming nature, although human beings have provided good material conditions for human survival, they have also exerted an impact on the original environment. Especially in the process of transforming nature, human beings have neglected the role of productivity movement and are also subject to nature, and have destroyed the natural balance in their constant pursuit of nature, In the process of constantly discharging waste to nature, serious environmental pollution has been caused. Therefore, for more than one hundred years, despite social development, economic growth and human progress, a series of problems such as global resource depletion and environmental pollution have also been caused. [1] ⑶ According to the function of environment, it can be divided into living environment and ecological environment. (This classification method is adopted in China's Constitution)
⑷ Human environment can be divided into the following categories according to spatial characteristics:
① Point environment: the environment centered on the human gathering place, such as urban environment , township environment, suburban transition zone and rural areas. ② Areal environment: large-scale artificial projects such as agriculture and forestry, such as farmland environment, artificial forest environment and water conservancy environment.
③ Linear environment: Highway environment And railway environment. According to the degree of human control, the artificial environment can be divided into complete artificial environment (such as the internal environment of aerial aircraft and deep-sea submarines) and incomplete artificial environment (such as human living environment such as urban buildings, factory breeding and planting bases, and cultural landscape in natural attractions).
In order to meet the needs of human survival and reproduction, human beings can meet their own needs by consciously and purposefully understanding and transforming the world's activities on the natural environment. Due to different purposes, different artificial environments have been formed, and the integration of artificial environment and natural environment has been achieved. With the progress of science and technology, the ability of human beings to control the environment has been strengthened, which is often ignored Natural environment elements This has resulted in a series of environmental problems that affect human survival or quality of life. [2] ① Obviously artificial
From the very beginning, any human environment is built to meet all kinds of human needs, which is the internal power of human impact on the environment and the reflection of human subjective will. When the goods provided by nature are not enough to meet human needs, human beings have used the natural environment and their own wisdom to generate great creativity, Transform the natural environment or create a new environment to meet its needs. For example, in order to be safe and comfortable, human beings need to build houses, towns and cities built of steel and concrete; In order to travel conveniently and quickly, human beings need all kinds of transportation tools and build transportation networks, forming a complex transportation network from sea, land and air; In order to satisfy the exploration of mysterious space, mankind has created various astronomical telescopes and space stations, realized the dream of landing on the moon, and now has begun to explore Mars.
② Diversification of artificial environment
Because human beings have diversity not only in material needs, but also in spiritual needs and creativity, with the improvement of human ability to control nature, human influence on the environment has also been strengthened and expanded, making the diversity of artificial environment increased. Taking artificial buildings as an example, starting from the time when humans bid farewell to natural caves and built primitive thatched houses, buildings not only provide living places for humans, but also provide sites for various social activities of humans, including the Great Wall of China, the Forbidden City, the Colosseum and Pantheon in Rome, the Acropolis in Athens, and the aerial flowers in Babylon in Cuba, Cities, villages, castles, squares, green spaces and sculptures with different modern styles have left rich cultural heritage for mankind, which fully demonstrates human creativity and cultural diversity. [2]
③ Vulnerability of artificial environment
For the artificial environment, the more modern, complex and artificial the environment is, the stronger the correlation and dependence between the factors inside and outside the system and those inside the system will be, natural environment The smaller the proportion in the system, the more vulnerable the environmental system will be. Once a problem occurs in one link, the whole environmental system will lose balance. For example, as early as the 2nd century BC, Loulan It is one of the most prosperous areas in the Western Regions. There are about 44100 people in Gululan State. Due to complex reasons such as nature and human activities, especially human interference, rivers are diverted and sandstorms are attacked, so the ancient city is buried in the desert. When power supply failure occurs in modern cities, it will cause factory shutdown, water supply and drainage stoppage, urban traffic chaos, affect the normal operation of residents' lives and other industries, as well as a series of chain reactions that may be brought about. ④ Serious environmental pollution
While human beings use and transform nature to form an artificial environment, they also discharge a large number of artificial pollutants to nature. Nature itself has a certain purification capacity, and maintains dynamic balance in the material and energy cycle. But this purification ability is not infinite, but there is a threshold When the artificial pollutants discharged by human beings exceed a certain limit, it will lead to serious environmental pollution, and the artificial environment is often the center of various environmental pollution. Environmental problems that affect global environmental change are often associated with human dispersion concentration areas, such as cities, industrial areas, agricultural areas and transportation networks. With the improvement of productivity, the urban area continues to expand, and the population is also increasingly concentrated. The pollutants discharged from production and life are increasing. The environmental pollution is becoming more and more serious. Taking urban air pollution as an example, the number of cars is increasing, becoming the main source of urban air pollution, causing CO 2、 NO two 、 hydrocarbon and Photochemical smog Such pollution is serious and difficult to solve. The scope of atmospheric pollution has gradually expanded to regional and even global pollution, and a series of atmospheric environmental problems have emerged, such as acid rain 、 greenhouse effect and Ozone layer destruction Etc. [2] 
