室内有害气体的来源与危害（The source and harm of indoor harmful gas）The types, sources and hazards of the main substances in indoor environmentThe environmental quality of indoor environmental pollution is influenced and polluted in many aspects, which can be divided into three categories. A: physical pollution, including noise, radiation, electromagnetic radiation and radioactive pollution, mainly comes from outdoor and indoor electrical equipment. B: chemical pollution, building decoration materials and furniture products in the release of volatile compounds of dozens of, with radon, formaldehyde, benzene, ammonia and so on four big the harm of indoor harmful gas is particularly acute. C: biological pollution, mainly mites, termites and other bacteria, mainly from carpets, blankets, wood products and structural subjects.The main source and harm caused by the improper decoration of formaldehyde, ammonia, radon gas, benzene, radioactive substances are the main sources of indoor environmental pollutants.A: the origin and hazard of radon gas. Radon gas is a kind of radioactive material which is precipitated from granite, cement, slag, block and gypsum building materials. Mainly comes from the inorganic material is given priority to with natural stone (granite, marble, gypsum, cement, sand, etc.) and the comprehensive utilization of slag and industrial waste residue after products (coal gangue brick, fly ash products).Radon is easy to enter into the lungs with human breath, harming the human respiratory organs and causing serious lung cancer. The radiation in natural stone can damage the human hematopoietic function, causing the occurrence of leukemia.B: source and hazard of formaldehyde. Formaldehyde is an organic compound, colorless and easy to dissolve, with strong pungent smell. The material mainly comes from interior decorative plywood, joinery board, medium density fiberboard and particleboard, and wood furniture made from plywood and inferior wood glue. Other kinds of adornment material, such as certain chemical fiber carpet, paint, wall paper, plastic foam, paint and some organic material also contain a certain amount of formaldehyde, its release period is 3 l5 years.Formaldehyde is stimulating to the eyes, mucosa and respiratory tract, which can cause pneumonia, pulmonary edema, menstrual disorders and neonatal deformity, which can lead to nasal cancer.C: sources and hazards of benzene. Benzene is a colorless and transparent liquid with a special aroma. It is less dense than water and is insoluble in water. It is often used as organic solvent. Benzene is found in paint, glue, paint and putty, and its release cycle is 2 3 weeks.When above a certain concentration of benzene content, but in a short time, make the person have a headache, chest tightness, nausea, vomiting, serious can make the person poisoning death, at the same time benzene can cause leukopenia, destroy peoples immune systems, severe cases can lead to leukemia and cardiovascular disease.D: sources and hazards of ammonia. Ammonia is colorless, strongly stimulating, volatile alkaline gas, lighter than air, solubility high. Mainly in the northern part of our country, many building commercial ammonia is used as antifreeze in cement for winter construction. As the change of environmental humidity, temperature, released from the wall, leading to higher concentration of ammonia in indoor air, in addition, the additives used in the furniture and the wood veneer finishing and whitening agent, and volatile out of ammonia. The release cycle of ammonia is 7 l0 days.Ammonia has a strong stimulation and corrosive effect on the upper airway, skin tissue and sensory system of the human body.Weakened the bodys resistance to disease. Light can cause dizziness, headache and tears, and the heavy can cause cardiac arrest and respiratory arrest through trigeminal nerve endings.E: other radioactive substances. Such natural granite as rhododendron, rhododendron, red, red and azote is highly radioactive, which can cause injury to the hematopoietic organs, nervous system and digestive system of the human body.A, formaldehydeFormaldehyde formaldehyde methanal methglene oxideFormaldehyde, an experiment of type, colorless gas, the molecular weight of 30.03, the relative density of the gas 1.067, 0.815 the density of liquid relative to the water (20 ), the boiling point 19.5 , soluble in water and ethanol. The content of aqueous solution can reach up to 55%.The stimulation threshold of formaldehyde to human eyes can be as low as 0.6 1.2 mg/m3, and the olfactory threshold of 0.03 0.6mg/m3.Source of formaldehyde:1) currently, formaldehyde is made of synthetic resin, paint, plastics and synthetic fiber raw material, is man-made board in the industrial manufacturing of urea-formaldehyde resin, melamine resin adhesive, polyacetal resin, e four aldol important raw material of resin and phenolic resin