1 the concept of green building materials The concept of green materials was first put forward at the first international conference on materials science in 1988. 1992, the international academic circles defined green materials as materials that have the least load on the earth's environment and are harmless to human health in the process of raw material adoption, product manufacturing, application and recycling after use. In the late 1970s, scientists and technicians in some industrialized countries began to study the influence of building materials on indoor air quality and its harm to human health, and conducted comprehensive and systematic basic research. In 1990s, more attention was paid to the development, research and application of green building materials, and the thinking gradually became clear. Some testing methods for the emission of organic volatiles were developed, which promoted the certification of low emission signs. At the same time, actively encourage the development and production of new green building materials and the construction of healthy houses. China's environmental pollution is in the forefront of the world, and the pollution level of Beijing, the capital, is one of the top ten most polluted cities in the world. In China 2 1 Century Agenda issued by China in 1992, protecting the environment and developing green products are important contents of sustainable development strategy. The State Environmental Protection Administration focuses on environmental labeling products and certification. At present, the interior decoration of residential buildings is in the ascendant. People not only pay attention to the pattern, color, material, workmanship and price of decoration, but also pay attention to whether the decoration materials used are harmful to human health. Recently, some newspapers, television and other news media reported personal injury accidents of newly renovated homeowners. There are also views on the harmfulness of some decoration materials, such as radon gas produced by granite decay, which may cause cancer if exposed to high concentration radon gas for a long time; In the production of wood composite board, urea-formaldehyde resin, phenolic resin or melamine-formaldehyde resin are often used as adhesives, which will release free formaldehyde in the process of use, making protein hard, and people who are exposed to high-concentration formaldehyde gas for a long time will lead to cancer. The film-forming additives used in coatings mainly include ethylene glycol monoethyl ether, ethylene glycol butyl ether, diethylene glycol and benzyl alcohol. Chloride solution or aromatic hydrocarbon in oily paint and lead heat stabilizer used in plastic products are very harmful to human body. On the one hand, these statements improve people's awareness of environmental protection when choosing materials, remind manufacturers to use less harmful substances in production, and on the other hand, people are at a loss when choosing decoration materials. Therefore, it is time to establish a correct concept for green building materials. However, the direct impact on human health is only one aspect of the connotation of green building materials, and as the development strategy of green building materials, we should conduct a comprehensive and systematic investigation from four aspects: raw material collection, product manufacturing, application process and recycling after use, so as to define whether it can be called green building materials. As we all know, environmental problems have become a serious problem that human development must face. After mankind continues to exploit the resources on the earth, the resources on the earth will inevitably become less and less. For the continuation of human civilization and the survival of the earth's creatures, human beings must change their concepts and attitudes towards nature, from blindly asking for it to cherishing resources, caring for the environment and living in harmony with nature. While mankind is actively looking for new resources, the most urgent thing at present is to consider the rational allocation and recycling of existing resources on the earth, meet the needs of contemporary social development without endangering future social development, and realize the unity of development and environment, and the combination of immediate and long-term development. 1-2 definition and basic characteristics of green building materials 1, definition of green building materials 1992, the international academic community clearly put forward the definition of green materials: green materials refer to materials that have the least load on the earth's environment and are beneficial to human health in the processes of raw material adoption, product manufacturing, use or recycling, waste disposal, etc., and are also called "environmentally harmonious materials". Building materials industry is a very important basic industry of national economy. It is one of the industries with the highest consumption of natural resources and energy, the most serious destruction of land resources and the most serious air pollution. Green building materials are also called ecological building materials, environmental protection building materials and healthy building materials. Green building materials adopt clean production technology, use less natural resources and energy, and use a lot of industrial or urban solid waste, which is non-toxic, pollution-free and non-radioactive, and is beneficial to environmental protection and human health. 2. Classification of green building materials In the general process of manufacture and use, the materials with relatively minimal load on the earth's environment are called "environmental materials" or "green materials"; Materials beneficial to environmental health are called "healthy environmental materials" or "environmentally friendly materials". However, environmental protection building materials are still in the research stage in the world. Traditional natural materials and most artificial new materials belong to the category of "green building materials". The concept of "healthy materials" refers to materials with specific environmental protection functions and health-friendly functions, which can have air purification, antibacterial and mildew-proof functions or electrochemical effects, infrared radiation effects, ultrasonic waves and electric field effects. "Green building materials" are mainly aimed at the environmental load of the earth, while "health care materials" refer to indoor microenvironment directly related to health, and some people always refer to them as "eco-environmental protection materials". "Ecological environment" refers to all human-related environments except natural conditions such as degassing, water, earth environment, light and heat. Therefore, "eco-environmental protection materials" can be divided into the following categories: (1) air environmental protection materials-air purification materials (2) water environmental protection materials-water purification materials (3) environmental protection materials-land improvement and waste residue utilization (4) recycling materials-zero emission of waste gas, waste water and waste residue (5) health and environmental protection materials 1). Basic characteristics of green building materials Compared with traditional building materials, green building materials can be summarized as the following five basic characteristics: 1. The raw materials used in its production use natural resources as little as possible, and a large number of wastes such as tailings, waste residue, garbage and waste liquid are used. 2. Adopt low energy consumption manufacturing technology and pollution-free production technology. 3, in the process of product preparation or production, formaldehyde, halide solvents or aromatic hydrocarbons shall not be used; Products must not contain mercury and its compounds; Pigments and additives of metals such as lead, cadmium and chromium and their compounds shall not be used. 4. The design of the product is aimed at improving the production environment and improving the quality of life, that is, the product is not only harmless to human health, but also beneficial to human health. This product has many functions such as antibacterial, sterilization, mildew prevention, deodorization, heat insulation, flame retardant, fire prevention, temperature regulation, humidity regulation, degaussing, radiation protection, antistatic and so on. 5. The product can be recycled or reused, which has no pollution to the environment. Green building materials meet the needs of sustainable development, realizing the unity of development and environment and the combination of modernity and long-term. It not only meets the needs of modern people, lives and works in peace, health and longevity, but also does not harm the greater demand of future generations for the environment and resources. In short, the development and greening process of building materials industry is not only related to the current development of building materials industry, but also related to whether it can be in line with international standards, whether it is related to the sustainability of the national economy and people's livelihood, whether it is related to the quality of life of our people, and whether it can contribute to the present and benefit the future. Therefore, we should strive to promote the development of all kinds of green building materials with a strategic vision, a sense of urgency of the times and a sense of historical responsibility, and build a healthy, safe, comfortable and beautiful building and indoor environment with green building materials for the benefit of society and people. 1-3 Significance of developing green building materials Since the 1970s, a series of global environmental problems such as ozone layer destruction, greenhouse effect and acid rain have become increasingly serious. People gradually realize that protecting the earth's environment on which we live is no longer just a matter for the government, non-governmental organizations and scientific research institutions. Everyone should take their own actions and directly participate in environmental protection. As a building material, in the process of production and use, on the one hand, it consumes a lot of energy, produces a lot of dust and harmful gases, and pollutes the atmosphere and environment; On the other hand, harmful gases will be emitted during use, which will have an impact on health for people who live for a long time. Encouraging and advocating the production and use of green building materials is very important for protecting the environment, improving people's quality of life and realizing sustainable economic development. Data show that about 40-50 billion tons of CO2 in nature is consumed by photosynthesis of green plants every year, and a considerable amount of CO2 is released into the atmosphere every year, such as respiration of animals and plants, decomposition and combustion of microorganisms, etc., so the CO2 content in the atmosphere has remained basically unchanged for thousands of years, and has been stable at 0.03% for a long time. However, in the past century, with the rapid development of modern industry and transportation, a large number of chemical fuels were burned and millions of tons of CO2 were released into the atmosphere, which seriously disturbed the dynamic balance of CO2 circulation in the atmosphere. According to the report of the United Nations Intergovernmental Panel on Climate Change (IPCC), the concentration of carbon dioxide in the atmosphere increased from 280PPm in 1800 to 364PPm in 1995, an increase of 30%. At present, it is increasing at the rate of 1.8PPm per year, and it is expected to exceed 600PPm in the new century, which will bring serious consequences to the changes of the earth's atmosphere. In order to solve the greenhouse effect, reduce CO2 emissions and recover CO2 emissions, many methods to control CO2 have been proposed. For example: (1) save energy and reduce the burning of fossil fuels; (2) Developing pollution-free energy such as hydrogen energy and atomic energy; (3) Separation, adsorption and reuse of 3)CO2; (4) Chemical and biological fixation of 4)CO2; (5) ocean fixation; (6) Underground or offshore storage, etc. In these methods, CO2 can be recovered by chemical and physical methods, such as gas absorption or membrane separation technology. The problem is how to deal with it after recycling, that is, how to turn it into other harmless or even useful substances. In addition, it is not only expensive to send the recovered CO2 to the sea or abandoned natural wells, but also the impact of CO2 stored in the sea on groundwater resources is unknown. According to the estimation of Ounma in Japan, whether it is solar power generation, CO2 separation and ocean storage, or planting plants, it will cost 30,000-40,000 yen per ton of CO2. Therefore, by using the above methods, it is difficult to achieve the level of CO2 emission reduction and effective utilization both technically and economically. China emits 2.3 billion tons of CO2 every year, 65.438+0.2 billion people and 600 million tons of CO2 in small living rooms, accounting for about 65.438+0/4 of the total emissions. In addition to CO2, what is more serious is that NO2 and SO2 emitted by combustion and motor vehicles are not only harmful to human body, but also produce acid rain and photochemical smog. When it comes to air pollution, people often only realize the air pollution in the big environment, but they don't know enough about indoor air pollution. In fact, indoor pollution is more direct to the human body. This small environment is an integral part of the big environment, which is closely related to people's daily life and health. Indoor pollutants include chemicals, radioactive substances, bacteria and other biological substances. The monitoring results of indoor air of various buildings by the US Environmental Protection Agency for five consecutive years show that thousands of chemicals have been found in indoor air so far, and some of them are 20 times more toxic than outdoor green spaces, which has threatened human health. In the first six months after the new building was completed, the content of toxic substances in the air was 100 times higher than that after the outdoor building was completed. As a result, many people suffer from "building aversion syndrome", that is, eye and nose discomfort, headache, fatigue, nausea and other discomfort symptoms, and even cancer. Therefore, it is our urgent responsibility to solve small environmental pollution and protect human health environment.