Volatile Organic Compounds (VOCs), which is the abbreviation of the first letter of volatile organic compounds, are often expressed by TVOC.

according to the definition of the world health organization (WHO), VOCs(volatile organic compounds) are various organic compounds with boiling points of 51℃ to 261℃ at room temperature. In China, VOCs refer to organic compounds with saturated vapor pressure greater than 71 Pa at normal temperature and boiling point below 261℃ at normal pressure, or all organic compounds with volatile vapor pressure greater than or equal to 11 Pa at 21℃.

it is usually divided into non-methane hydrocarbons (NMHCs for short), oxygen-containing organic compounds, halogenated hydrocarbons, nitrogen-containing organic compounds and sulfur-containing organic compounds. VOCs are involved in the formation of ozone and secondary organic aerosol in the atmospheric environment, and they have made important contributions to regional atmospheric ozone pollution and PM2.5 pollution. Most VOCs have unpleasant special odor, and are toxic, teratogenic and carcinogenic, especially benzene, toluene and formaldehyde, which will do great harm to human health. VOCs are important precursors of urban haze and photochemical smog, which mainly come from coal chemical industry, petrochemical industry, fuel coating manufacturing, solvent manufacturing and use. Chinese Name: Volatile Organic Compounds mbth: VOCs for short: VOCs Definition: Sources of organic compounds involved in atmospheric photochemical reactions: artificial sources and natural sources Classification of pollution sources: introduction of stationary sources and mobile sources, sources, present situation and classification, hazards and prevention and control technical policies. According to their different chemical structures, the introduction can be further divided into eight categories: alkanes, aromatics, alkenes, halogenated hydrocarbons, esters and aldehydes. The main components of VOC are hydrocarbons, halogenated hydrocarbons, oxygen hydrocarbons and nitrogen hydrocarbons, including benzene series, organic chlorides, Freon series, organic ketones, amines, alcohols, ethers, esters, acids and petroleum hydrocarbons. Sources, present situation and classification The main sources of VOC are: outdoor, mainly from industrial waste gas generated by fuel combustion and transportation, automobile exhaust, photochemical pollution, etc. But indoors, it mainly comes from combustion products such as coal and natural gas, smoke from smoking, heating and cooking, building and decoration materials, furniture, household appliances, automobile interior parts production, cleaning agents and human body's own emissions. In the process of interior decoration, VOC mainly comes from paints, coatings and adhesives, and solvent-based release agents. Generally, the VOC content in paint is 1.4-1.1mg/m3. Due to the strong volatility of VOC, in general, 91% of the paint can be volatilized within 11 hours after the paint is applied, while the VOC in the solvent only releases 25% of the total amount during the paint drying process. Volatile organic compounds (VOCs) are important precursors for the formation of secondary pollutants such as fine particles (PM2.5) and ozone (O3), which in turn cause atmospheric environmental problems such as haze and photochemical smog. With the rapid development of industrialization and urbanization in China and the sustained growth of energy consumption, regional compound air pollution characterized by PM2.5 and PM 2.5 has become increasingly prominent, and the frequency of large-scale simultaneous air pollution in the region has increased, which seriously restricts the sustainable development of social economy and threatens people's health. In order to fundamentally solve the pollution problems such as PM2.5 and O3, and effectively improve the quality of the atmospheric environment. The state should actively promote the pollution prevention and control of its key precursor VOCs. However, at present, the foundation of VOCs pollution prevention and control in China is weak, and there are many problems such as unclear emission base, imperfect laws and regulations, lagging application of control technology, and inadequate environmental supervision. At the same time, it is difficult to establish a VOCs pollution prevention and control system because of the complex emission sources, various emission forms and various substances. Therefore, it is an urgent, arduous and complicated task to carry out VOCs pollution prevention and control in an all-round way in line with China's reality. Classification of volatile organic pollution There are many kinds of volatile organic pollution. There is no unified classification method at present, and the common classification is based on the nature of pollution sources, which mainly includes the following: 1) Organic solution. Organic solution is a solvent with organic matter as the composition medium. Common organic solutions include household cosmetics, shampoo and detergent, as well as daily tools such as adhesives, paints and aqueous coatings. 2). Building materials. Building materials refer to some volatile materials used in construction projects, including paints, plastic rice materials, foam insulation materials, artificial plates and other materials used indoors and outdoors. 3). Interior decoration materials. Interior decoration materials refer to building interior coatings or some other materials that are easy to volatilize odor, including wall coatings, wallpapers, murals and other materials that are easy to generate volatile odor. 4). Fiber materials. Fiber materials are materials made of natural fibers or synthetic fibers, which can usually be used as carpets, tapestries, chemical fiber curtains and other supplies. 5). Office supplies. Some office Sichuan products have their own volatility. For example, ink, and some of them are not volatile, but they emit a lot of heat during their work, and some of their consumables are emitted together with the heat, such as photocopiers and printers, which emit a lot of harmful gases into the air during their work. 6). Outdoor industrial gas. Outdoor industrial gas refers to the gas emitted by industrial production or various machinery, which has a wide range, including the gas volatilized during industrial production, automobile exhaust, photochemical smog and so on. Harmful indoor VOC pollution has attracted attention from all countries. The effects of volatile TVOC on human health are mainly * * * eyes and respiratory tract, causing skin allergy, headache, sore throat and fatigue, which also contains many carcinogens. The TVOC content in the indoor air has become an important item to evaluate whether the indoor air quality of the living room is qualified or not in the Code for Indoor Environmental Pollution Control of Civil Buildings promulgated by the new national government. The TVOC content specified in this standard is 1.5 mg/ m3 for Class I civil construction projects and 1.6mg/ m3 for Class II civil construction projects. Most VOCs are toxic. Some VOCs are carcinogenic. For example, some harmful substances in the atmosphere, such as benzene, polycyclic aromatic hydrocarbons, aromatic amines, resin compounds, aldehydes and nitrosamines, have carcinogenic effects or real tumor effects on the body; Some aromatic amines, aldehydes, haloalkanes and their derivatives, and vinyl chloride have mutagenic effects. Most volatile organic compounds are flammable, explosive and unsafe. Under sunlight, volatile organic compounds react with nitrogen oxides, hydrocarbons and oxidants in the atmosphere to generate photochemical fog, which is harmful to human health and crop growth. ) The main components of chemical fog are ozone, peroxyacetyl nitrate (PAN), aldehydes and ketones. They affect people's eyes and respiratory system. Harm people's health and crop growth. Meat hydrocarbons VOCs can destroy the ozone layer; Such as chlorofluorocarbon ((CFCs)

technical policy I. General Provisions (I) This technical policy is formulated to implement the Environmental Protection Law of the People's Republic of China, the Air Pollution Prevention Law of the People's Republic of China and other laws and regulations, prevent and control environmental pollution, ensure ecological safety and human health, and promote the technical progress of volatile organic compounds (VOCs) pollution prevention and control. (two) this technical policy is a guiding file for all relevant units to refer to in environmental protection work. (III) This technical policy puts forward pollution prevention strategies and methods in the production, storage, transportation, sales, use and consumption of VOCs-containing materials and products. VOCs have a wide range of sources, and the main pollution sources include industrial sources and domestic sources. Industrial sources mainly include oil refining, petrochemical industry, coal processing and conversion and other VOCs-containing raw materials production industries, the storage, transportation and sales processes of oils (fuels, solvents, etc.), the production industries taking VOCs as raw materials such as paints, inks, adhesives and pesticides, and the use processes of VOCs-containing products such as painting, printing, bonding, demoulding and industrial cleaning. Living sources include architectural decoration, catering service and clothing dry cleaning. The prevention and control of VOCs pollution from oil and gas exploration, pharmaceutical industry and motor vehicles can refer to the corresponding pollution prevention and control technical policies respectively. (4) The prevention and control of VOCs pollution should follow the comprehensive prevention and control principle of combining source and process control with terminal treatment. Adopt clean production technology in industrial production, strictly control the VOCs emission of raw materials and products containing VOCs during production, storage, transportation and marketing, and encourage the recycling of resources and energy; Encourage the use of alternative products without VOCs or products with low VOCs content in production and life. (5) By actively conducting a thorough investigation of VOCs, compiling and revising the archives of VOCs emission standards and management systems in key industries, strengthening the monitoring and management of VOCs, and promoting the use of environmental labeling products, the VOCs pollution prevention and control system in key areas will be basically established by 2115; By 2121, VOCs will be basically reduced in the whole process from raw materials to products and from production to consumption. II. Source and Process Control (VI) In the petroleum refining and petrochemical industries, advanced cleaner production technologies are encouraged to improve the conversion and utilization efficiency of crude oil. The technical measures for prevention and control of VOCs-containing waste gas pollution from equipment and pipeline components, process exhaust, waste gas burning tower (torch), waste water treatment and other processes include: 1. Make LDAR (LDAR) plan for equipment and pipeline components that are prone to leak, such as pumps, compressors, valves and flanges, and conduct regular inspection and timely repair to prevent or reduce leakage; 2. The VOCs-containing process exhaust gas discharged from production devices should be recycled first, and those that cannot be (or cannot be) recycled should be discharged up to standard after treatment; In case of emergency, the venting gas can be introduced into the combustion tower (torch) and discharged after full combustion; 3. The VOCs-containing waste gas generated in the process of wastewater collection and treatment is discharged up to the standard after collection and treatment. (VII) In the coal processing and conversion industry, encourage the adoption of advanced cleaner production technology to realize efficient and clean conversion of coal, and focus on identifying and troubleshooting the prone positions of VOCs leakage in process devices and pipeline components, and formulate measures to prevent VOCs leakage and deal with emergencies. (8) The technical measures to prevent and control VOCs pollution in the process of storage, transportation and sales of oils (fuels and solvents) include: 1. Oil storage tanks, gas stations and tanker trucks should be equipped with corresponding oil and gas collection systems, and oil storage tanks and gas stations should be equipped with corresponding oil and gas recovery systems; 2. Oil (fuel oil, solvent, etc.) storage tanks should adopt high-efficiency sealed internal (external) floating roof tanks. When a fixed roof tank is used, the gas containing VOCs will be transported to the recovery equipment through a closed exhaust system; 3. The VOCs discharged from oil (fuel, solvent, etc.) vehicles (automobile tankers, railway tankers, oil tankers, etc.) during the loading process are collected and transported to recovery equipment in a sealed manner, and can also be returned to storage tanks or sent to gas pipe networks. (9) Technical measures for prevention and control of VOCs pollution in production industries that use VOCs as raw materials, such as paints, inks, adhesives, release agents and pesticides, include: 1. Encourage the production and sale of water-based, non-organic and low-organic paints, inks and adhesives that meet the technical requirements of environmental labeling products; 2 to encourage the use of closed integrated production technology, and the waste gas generated in the production process is classified and collected for post-treatment. (11) Technical measures to prevent and control VOCs pollution in the process of using products containing VOCs such as painting, printing, bonding and industrial cleaning include: 1. Encourage the use of environmentally-friendly paints, inks, adhesives and cleaning agents that have passed the certification of environmentally-friendly products; 2. According to the different coating processes, encourage the use of water-based coatings, high-solid coatings, powder coatings, ultraviolet curing (UV) coatings and other environmentally friendly coatings; Promote the use of electrostatic spraying, flow coating, roller coating, dip coating and other efficient coating processes; Open-air spraying operation without VOCs purification and recovery measures should be avoided as far as possible; 3. Promote the use of water-based ink in the printing process, encourage the use of ultraviolet curing (UV) ink in the tin printing and canning industry, and encourage the use of pre-coating film technology in the book printing industry; 4. Encourage the use of water-based and hot-melt environmental-friendly adhesives in the bonding process of wood-based panels, shoes, leather products and packaging materials, and promote solvent-free compounding and * * * extrusion compounding technology in the production of composite films; 5. Eliminate production processes that use trifluorotrichloroethane, methyl chloroform and carbon tetrachloride as cleaning agents or solvents. The waste solvent generated in the cleaning process should be collected in a sealed way, the waste solvent with recycling value should be reused after treatment, and other waste solvents should be properly disposed of; 6. During the use of VOCs-containing products, waste gas collection measures should be taken to improve the efficiency of waste gas collection, reduce the unorganized emission and escape of waste gas, and recover or treat the collected waste gas and discharge it up to standard. (11) Technical measures to prevent and control VOCs pollution from living sources such as building decoration, clothing dry cleaning, cooking fume, etc. include: 1. Promote the use of building coatings, low organic solvent-based wood paints and adhesives that meet the technical requirements of environmental labeling products in the building decoration industry, and gradually reduce the use of organic solvent-based coatings; 2. In the clothing dry cleaning industry, we should eliminate the production and use of open dry cleaning machines, promote the use of closed dry cleaning machines equipped with compressor refrigeration solvent recovery system, and encourage the use of dry cleaning machines equipped with activated carbon adsorption devices; 3. Encourage the use of clean energy such as pipeline gas, natural gas and electricity in the catering service industry; Advocate a diet with low oil smoke, low pollution and low energy consumption. III. Terminal Treatment and Comprehensive Utilization (XII) Encourage the recycling of VOCs in the industrial production process, and give priority to the recycling in the production system. (13) For waste gas containing high concentrations of VOCs, condensation recovery and adsorption recovery technologies should be given priority for recycling, and other treatment technologies should be assisted to achieve emission standards. (14) For the waste gas containing VOCs with medium concentration, the organic solvent can be recovered by adsorption technology, or the waste gas can be discharged after purification by catalytic combustion and thermal incineration technology. When catalytic combustion and thermal incineration technology are used for purification, waste heat should be recycled. (15) For waste gas containing low-concentration VOCs, adsorption technology and absorption technology can be used to recover organic solvents and discharge them up to standard when there is recycling value; When it is not suitable for recycling, adsorption concentration combustion technology, biotechnology, absorption technology, plasma technology or ultraviolet advanced oxidation technology can be used for purification and discharge. (16) Waste gas containing organic halogen component VOCs should be treated by non-incineration technology. (17) The sources of malodorous gas pollution can be purified by biotechnology, plasma technology, adsorption technology, absorption technology, advanced ultraviolet oxidation technology or combined technology. In addition to meeting the requirements of standard discharge, the purified malodorous gas should also be discharged at high altitude to avoid disturbing the people. (eighteen) in the catering service industry to promote the use of oil smoke exhaust device with oil mist recovery function, and according to the scale, site and climatic conditions, etc ..