The first category-chemical pollution: mainly from decoration, furniture, toys, gas water heaters, insecticidal spray, cosmetics, smoking, kitchen fumes, etc.
The second category-physical contamination: noise, light and radioactive pollution of outdoor and indoor electrical equipment;
The third category-biological pollution: mainly comes from indoor decoration materials, daily necessities, mites and other bacteria parasitic on air conditioners.
The interaction of these harmful substances will aggravate the harm of indoor pollution to human health. For example, chemical pollution in indoor air will irritate and inflame human skin, mucosa and conjunctiva, even paralyze respiratory cilia and damage mucosal epithelial tissue. In this case, the human body's resistance to diseases will be greatly weakened, making it easy for pathogenic microorganisms to invade and endangering people's health. Therefore, people should pay attention to indoor environmental pollution, especially new houses and newly renovated families.
(1) Types and sources of chemical pollutants in indoor environment
Chemical pollutants in indoor environment mainly include formaldehyde, benzene, toluene, xylene, ammonia, sulfur dioxide, nitrogen dioxide, carbon monoxide, carbon dioxide, TVOC and inhalable particles.
1. What are the sources and hazards of formaldehyde in indoor environment?
Formaldehyde is a five-color, irritating and water-soluble gas. It can coagulate protein, and its aqueous solution with a concentration of 35% ~ 40% is commonly known as formalin, which is often used as a solution for impregnating specimens. Formaldehyde in indoor environment can be roughly divided into two categories according to sources:
1) outdoor air pollution: industrial waste gas, automobile exhaust, photochemical smog, etc. Can release or produce a certain amount of formaldehyde to a certain extent, but the content of this part is very small. According to relevant reports, the annual average concentration of formaldehyde in urban air is 0.005 ~ 0.olmg/m3,, generally not exceeding 0.03mg/m3. This part of gas can enter people's rooms at some time and is a source of indoor formaldehyde pollution.
2) Indoor pollution: formaldehyde mainly comes from wood-based panels and is mainly used for production; Decoration materials and new combination furniture are the main sources of formaldehyde pollution; Adhesives of plywood, core board, medium density fiberboard and particleboard in decoration materials and furniture release formaldehyde when heated and deliquesced, which is the main source of indoor formaldehyde release; UF foam is used as thermal insulation material to protect houses from heat and cold, and the foam ages under the action of light and heat. Paint, chemical fiber carpet, cosmetics and other products with formaldehyde as preservative; Smoking indoors.
So generally speaking, the sources of formaldehyde in indoor environment are still very extensive. Generally, the formaldehyde content of newly renovated houses can exceed the standard by more than 6 times, and some may exceed the standard by more than 40 times. The research shows that the content of formaldehyde in indoor environment is closely related to the use time, temperature, humidity and ventilation of the house. Generally speaking, the longer the house is used, the less formaldehyde remains in the indoor environment; The higher the temperature, the greater the humidity, which is more conducive to the release of formaldehyde; The better the ventilation conditions, the more conducive to the release of formaldehyde in building and decoration materials.
The measured data show that the formaldehyde concentration can be lower than 0. 1 mg/m3 after 5 months of indoor decoration under normal decoration. After 7 months of transformation, it can be reduced to below 0.08 mg/m3. The release period of indoor formaldehyde will last for several years.
Formaldehyde has been identified as a carcinogen and teratogenic substance by the World Health Organization. It is considered as an allergen and one of the potential strong mutagens.
Studies have shown that formaldehyde has a strong carcinogenic and cancer-promoting effect. According to a large number of documents, the effects of formaldehyde on human health are mainly manifested in abnormal smell, irritation, allergy, abnormal lung function, abnormal liver function and abnormal immune function. When its concentration reaches 0.06 ~ 0.07 mg/m3 per m3 of air, children will have mild asthma. When the formaldehyde content in indoor air is 0. 1mg/m3, it will have peculiar smell and make people uncomfortable. When it reaches 0.5mg/m3, it can irritate eyes and cause tears; Up to 0.6 mg/m3, which may cause throat discomfort or pain. When the concentration is high, it can cause nausea and vomiting, cough and chest tightness, asthma and even pulmonary edema; When it reaches 30mg/m3, it will kill people immediately.
Long-term exposure to low-dose formaldehyde can cause chronic respiratory diseases, nasopharyngeal carcinoma, colon cancer, brain tumor, menstrual disorder, gene mutation in the nucleus, DNA single-strand cross-linking and DNA-protein cross-linking, inhibition of DNA damage repair, pregnancy syndrome, chromosomal abnormalities in newborns, leukemia, and memory and intelligence decline in adolescents. Among all the contacts, children and pregnant women are particularly sensitive to formaldehyde, which is more harmful.
The working group of the World Health Organization (WHO) has defined the potential carcinogenic threshold of formaldehyde to odor, eye irritation and respiratory irritation, and pointed out that when the formaldehyde concentration in indoor environment exceeds 10%, it should be paid enough attention.
2. What are the sources and hazards of benzene in indoor environment?
The main sources of benzene in indoor environment are tobacco smoke, solvents, paints, dyes, fax machines, computer terminals and printers, adhesives, wallpaper, carpets, synthetic fibers and detergents.
Benzene, toluene and xylene are often collectively referred to as triphenyl in industry. Of these three substances, benzene is the most toxic.
It is generally believed that benzene poisoning is caused by metabolites, which means that benzene must be metabolized before it can cause harm to life. Benzene can be metabolized in liver and bone marrow, and bone marrow is the place where red blood cells, white blood cells and platelets are formed, so benzene itself can form toxic metabolites in hematopoietic tissue. Long-term exposure to benzene can cause bone marrow and genetic damage, and hemogram examination can find leukopenia, thrombocytopenia, pancytopenia, aplastic anemia and even leukemia. Someone has investigated the health status of workers exposed to low concentrations of benzene. The results showed that the number of white blood cells in peripheral blood was within the normal range, but it was significantly lower than that in the control group. The distribution of lymphocyte micronucleus rate in benzene exposed workers was higher than that in non-benzene exposed workers, and there was significant difference between the observation group and the control group. With the increase of benzene concentration in the working environment, the number of white blood cells tends to decrease and the micronucleus rate of lymphocytes tends to increase. All these prove that low concentration of benzene is harmful to workers' health, especially to human genetic material.
Inhalation of benzene above 4000ppm for a short time not only stimulates mucous membrane and lung, but also inhibits central nervous system, accompanied by headache, nausea, gait instability, coma, convulsion and arrhythmia.
Inhalation of benzene above 14000ppm will lead to immediate death.
3. What are the sources and hazards of toluene in indoor environment?
Toluene mainly comes from some solvents, perfumes, detergents, wallpaper, adhesives, paints and so on. The amount of toluene produced by smoking in indoor environment is also considerable. According to American EPA statistics, the toluene content in mainstream smoke of filter-less cigarettes is about 100 ~ 200 ug, and the toluene concentration ratio of side/mainstream smoke is 1.3.
About 48% of toluene is metabolized in the body and eventually excreted through the liver, brain, lung and kidney, which will do harm to the nervous system. Experiments of volunteers show that when the concentration of toluene in blood reaches 1250mg/m3, the short-term memory ability, attention persistence and sensory motor speed of contacts are significantly reduced.
4. What are the sources and hazards of xylene in indoor environment?
Xylene comes from solvents, pesticides, polyester fibers, tapes, adhesives, wallpapers, paints, wet copiers, laminated products and carpets.
Xylene includes ortho-,meta-and para-isomers, with the largest meta-proportion reaching 60% ~ 70% and the lowest para-content. Xylene can be absorbed through respiratory tract, skin and digestive tract, and its vapor enters human body through respiratory tract, and some of it is discharged through respiratory tract. The absorbed xylene is most distributed in adipose tissue and adrenal gland, followed by bone marrow, brain, blood, kidney and liver. The toxicity of three isomers of industrial xylene is slightly different, and they all belong to low toxicity. It is reported that three workers inhaled xylene with a concentration of 43. 1g/m3, and 1 person died after 18.5 hours. Autopsy showed pulmonary congestion and cerebral hemorrhage, and the other two workers lost consciousness 19 ~ 24 hours, accompanied by memory loss and renal function changes. In addition, inhaling high concentration of xylene can cause loss of appetite, nausea, vomiting and abdominal pain, and sometimes it can cause reversible damage to liver and kidney. At the same time, xylene is also an anesthetic, and long-term exposure will cause nervous system dysfunction.
5. What are the main sources and hazards of ammonia in indoor environment?
Residential buildings, office buildings, hotels and restaurants under construction. In northern China, people artificially add additives such as urea-containing high-alkali concrete expansion agent and concrete antifreeze to prevent concrete from freezing and cracking in winter construction, which greatly improves the construction progress. These additives containing a large amount of ammonia are reduced to ammonia in the wall with the changes of environmental factors such as humidity and temperature, and are slowly released from the wall, resulting in a large increase in the concentration of ammonia in indoor air.
At the same time, ammonia in indoor air can also come from indoor decoration materials, such as additives and brighteners used in furniture finishing, and most of them use ammonia water. Ammonia water is widely used as a neutralizer in shampoo shops and beauty salons.
In addition, with the deepening of people's understanding of the destruction of ozone layer by chlorofluorocarbons, the use of chlorofluorocarbons as refrigerants has been banned all over the world. Ammonia that has been used for a century and a half is used again. This is also a potential pollution source.
According to toxicological classification, ammonia belongs to low toxic compounds. Ammonia is a colorless gas. When the ammonia in the ambient air reaches a certain concentration, it has a strong pungent smell. The threshold of human smelling ammonia is 0.5- 1.0mg/m3. Ammonia is an alkaline substance, which can absorb water in tissues after entering the human body, and has high solubility, which can stimulate and corrode the upper respiratory tract of the human body and weaken the resistance of the human body to diseases. After ammonia enters the alveoli, it is easy to combine with hemoglobin and destroy the transport function of oxygen. Inhaling a large amount of ammonia in a short period of time can cause tears, sore throat, hoarseness, cough, dizziness, nausea and other symptoms. In severe cases, pulmonary edema or respiratory distress syndrome will occur, and respiratory irritation symptoms will occur at the same time. According to the regulations of American Association of Manufacturing Chemists, workers are allowed to work for 8 hours when the ammonia concentration is lower than 1mppn.
6. What are the sources and hazards of sulfur dioxide in indoor environment?
Sulfur dioxide is a colorless gas with a strong pungent smell. The pollution of sulfur dioxide to indoor environment is related to family cooking style, ventilation, indoor structure and fuel weight. Most farmers in rural areas of China mainly burn briquettes, briquettes and honeycomb briquettes. Due to the unreasonable structure of the stove, coal can't burn completely, and a large number of pollutants are emitted, mainly sulfur dioxide, which will also be produced when smoking. Studies have shown that the content of sulfur dioxide in indoor air of coal-fired households is much higher than that of gas-fired households, which can reach 0.86mg/m3 in the kitchen and 0.50mg/m3 in the bedroom in winter.
The target cell of sulfur dioxide is mainly the upper respiratory tract, because it is easily soluble in water to form sulfurous acid, which irritates the eyes and nasal mucosa and is corrosive; Sulfur dioxide has a high solubility in tissue fluid, so the sulfur dioxide inhaled in the air will quickly dissolve and disappear in the upper respiratory tract and rarely enter the deep airway, so it is only possible to enter the lungs when taking a deep breath or when sulfur dioxide is adsorbed on the surface of dust particles.
On the one hand, people who have been exposed to sulfur dioxide for a long time stimulate the upper respiratory tract to cause reflex contraction of bronchial smooth muscle, increase respiratory resistance and decrease respiratory function; On the other hand, it stimulates and loses mucous membrane, which increases and thickens mucous membrane secretion, hinders ciliary movement, weakens immune function, leads to decreased respiratory resistance, and induces different degrees of inflammation, such as chronic nasopharyngitis, chronic bronchitis, bronchial asthma and emphysema. In addition, long-term exposure to sulfur dioxide has a negative impact on the function of cerebral cortex, which makes the brain's labor ability decline, which is not conducive to children's intellectual development.
7. What are the sources of nitrogen dioxide in indoor environment?
Usually, people refer to nitrogen oxides as the general term of nitric oxide and nitrogen dioxide. Nitric oxide can be easily converted into nitrogen dioxide in the air. The nitrogen oxides in the indoor environment are mainly due to the burning of fuel during cooking and heating, and also produce nitrogen oxides when smoking. Coal is the main fuel for urban households in China, including raw coal and briquette, accounting for about 50% ~ 80% of the total fuel, followed by gas and liquefied gas, accounting for about 20% ~ 50%. Most rural areas are dominated by coal and biofuels.
The results show that the daily average concentrations of nitrogen oxides in the air of kitchens and bedrooms burning raw coal in winter are 0. 159mg/m3 and 0. 132mg/m3, respectively. The daily average concentrations of nitrogen oxides in the air of coal-burning kitchen and bedroom are 0.09 1mg/m3 and 0.078mg/m3, respectively, and the daily average concentrations of nitrogen oxides in the air of kitchen and bedroom burning liquefied gas are 0.070mg/m3. The daily average concentration of nitrogen oxides produced by using three fuels in summer is lower than that in winter. Therefore, the generation of nitrogen oxides in indoor environment is not only related to the energy structure, but also varies with the seasons.
8. What are the sources of carbon monoxide in indoor environment?
Carbon monoxide in indoor environment mainly comes from smoking, heating equipment and kitchen. A cigarette can usually produce about 13 mg of carbon monoxide. For cigarette paper with high permeability, it can promote the complete combustion of cigarettes and produce less carbon monoxide. Carbon monoxide produced by heating equipment and kitchen is mainly caused by incomplete combustion of fuel.
9. What are the sources of carbon dioxide in the indoor environment?
Indoor air with carbon dioxide below 0.07% belongs to clean air, which makes people feel good. When the concentration is 0.07% ~ 0. 1%, it belongs to ordinary air, and some sensitive person will feel bad smell; When 0. 1% ~ 0. 15%, it belongs to critical air, and other symptoms of indoor air begin to deteriorate, and people begin to feel uncomfortable; When it reaches 0. 15% ~ 0.2%, it belongs to cleanliness pollution, and more than 0.2% belongs to serious pollution; 0.3% ~ 0.4% of people, breathing deepens, and symptoms such as headache, tinnitus, and elevated blood pressure appear. If it reaches more than 0.8%, it will lead to death.
10, what are the inhalable particles in the indoor environment?
Particles smaller than 10 UN (PM 10): refers to the aerodynamic equivalent diameter (10 micron) suspended in the air. There are many sources of particulate matter in the air. Dust, bacteria, hair, dandruff, ticks, dust, smoke and harmful substances in the air combine with inhalable particles to form very harmful allergens.
1 1. What are the classification and sources of volatile organic pollutants (VOCs) in indoor environment?
Volatile organic pollutants are divided into four categories: extremely volatile organic compounds (VVOCs), volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs) and organic matters related to particulate matter or particulate organic matter (POM). VOCs basically represent the pollution status of organic matters in indoor organic pollutants detection. During the period of 1989, the US Environmental Protection Agency detected more than 900 indoor VOCs.
VOCs in indoor environment are mainly released from building materials, detergents, paints, waterborne coatings, adhesives, cosmetics and detergents, and are also produced during smoking and cooking.
1984 the report of the world health organization "understanding and paying attention to indoor air pollutants" lists common indoor VOCs, as shown in the following table:
pollutant
source
formaldehyde
Insecticide, paperboard products, UFFI, hardwood plywood, adhesive, particleboard, laminate, paint, plastic, carpet, soft plastic furniture cover, gypsum board, adhesive, ceiling and wallboard, non-latex joint filler, acid-cured wood paint, wooden wallboard, plastic/melamine wallboard, vinyl (plastic) floor tile and vinyl (plastic) floor tile.
benzene
Smoke, solvents, paints, dyes, varnishes, fax machines, computer terminals and printers, adhesives, latex caulking agents, water-based adhesives, wood siding, carpets, floor tile adhesives, stain/textile cleaners, polystyrene foam, plastics, synthetic fibers.
carbon tetrachloride
Solvent, refrigerant, spray, fire extinguisher, grease solvent
trichloro ethylene
Solvent, dry cleaning cloth, soft plastic furniture cover, ink, paint, varnish, adhesive, fax machine, computer terminal and printer, typewriter correction fluid, paint remover and detergent.
tetrachloroethylene
Dry cleaning fabrics, soft plastic furniture covers, stain/textile cleaning agents, fax machines, computer terminals and printers.
chloroform
Solvent, dye, pesticide, fax machine, computer terminal and printer, soft plastic furniture cushion, chloroform water.
1, 2- dichlorobenzene
Dry cleaning additive, degreasing agent, insecticide, carpet.
1, 3- dichlorobenzene
Insecticide
1, 4- dichlorobenzene
Deodorant, mildew inhibitor, air freshener/deodorant, toilet and garbage can deodorant, pest control pills and pest control tablets.
ethylbenzene
Styrene-related products, synthetic polymers, solvents, fax machines, computer terminals and printers, polyurethane, furniture polish, adhesives, latex and non-latex caulking compounds, floor tile adhesives, carpet adhesives, painted hardwood parquet.
toluene
Solvent, perfume, detergent, dye, water-based adhesive, edge sealer, molding tape, wallpaper, adhesive, silicate sheet, vinyl (plastic) coated wallpaper, caulking material, paint, carpet, wood pressing decoration, vinyl (plastic) floor tile, paint (latex and solvent), carpet adhesive and grease solvent.
xylene
Solvent, dye, insecticide, polyester fiber, adhesive, adhesive compound, wallpaper, caulking compound, varnish, resin and ceramic coating, carpet, wet copier, pressed product, gypsum board, water-based adhesive, grease solvent, paint, carpet adhesive, vinyl (plastic) floor tile and polyurethane coating.
(2), indoor environmental radioactive pollution and harm
What are the natural radioactive sources?
There are many kinds of natural radionuclides with different properties and states, which are widely distributed in the environment. There are traces of natural radionuclides in rocks, soil, air, water, animals and plants, building materials, food and even human body. The crust is an important repository of natural radionuclides, especially primary radionuclides. The radioactive substances in the earth's crust are mainly uranium, thorium and uranium. Among them, the natural radionuclides in the air are mainly radionuclides released from the surface and their daughters in the atmosphere, and the natural radionuclides in animal and plant foods are mostly.
Soil is mainly produced by the erosion and weathering of rocks, which shows that radioactivity is transferred from rocks. Because of the variety of rocks and the different influence of natural conditions, it can be predicted that the concentration of natural radionuclides in soil changes greatly. The geographical location, geological sources, hydrological conditions, climate and agricultural history of soil are all important factors affecting the content of natural radionuclides in soil.
Radioactive substances existing in rocks and soil are lost due to leaching of groundwater, and natural radionuclides in groundwater mainly come from this way. In addition, the radionuclides attached to the surface granular soil can be transformed into dust or aerosol under the action of wind, and then transferred to the atmosphere and further migrated to plants or animals. Some soluble radionuclides in soil are absorbed by plant roots, then transported to edible parts, eaten by herbivores, and then transferred to carnivores, and finally become one of the important sources of radionuclides in food and human body. The concentration of natural radionuclides in environmental water is related to many factors.
In addition, natural radioactive substances also include cosmic rays. Cosmic rays are a stream of high-energy particles emitted from space to the earth. It consists of protons, particles, etc. Natural radioactivity has adapted to human beings without causing any harm.
2. What harm does radon do to human body?
Radon enters the human body through breathing, and the short-lived radionuclides produced during decay will be deposited in the bronchi, lungs and kidneys. When these short-lived radioactive nuclei decay, the released particles are the most harmful to internal irradiation and can cause radiation to epithelial exchange cells of respiratory system. Long-term irradiation may cause local tissue damage and even induce lung cancer and bronchial cancer. It is estimated that 30- 120 people per thousand will die of lung cancer if they live in an indoor environment with radon concentration of 370Bq/m3 in their lifetime. Radon and its daughters will also emit strong penetrating rays when they decay, which will cause external irradiation to human body.
If you live in an environment with high radon content for a long time, it may cause harm to people's blood circulation system, such as leukopenia, thrombocytopenia and even leukemia.
This kind of harm has a heavy lesson: 1922, many Egyptian archaeologists excavated the tomb of the ancient Egyptian Pharaoh Tutankhamun, and then died strangely. Since then, the theory of Pharaoh's curse has spread like wildfire. It is said that the ancient Egyptians put a curse on the pyramids and killed those who broke into them. Recently, indoor environmental experts in Canada and Egypt have solved the mystery of this curse that has plagued people in recent years. They found that the pyramids contained a lot of dangerous radon gas, which caused the contact to get lung cancer and die. Experts found that this deadly radon gas was released from decaying uranium in pyramid stones and soil. The three ancient Egyptian buildings with the highest radon content are Shakamkat Pyramid in the south of Cairo, Abbiss Tunnel and Youm Mausoleum in Salabi. Baxter, an indoor environmental expert, said: "It is the high radon content that harms the health of Egyptian archaeologists."
3. How to prevent the harm of radon to human body?
Because the harm of radon is accumulated for a long time and is not easy to be detected, we must attach great importance to it and do a good job in publicity and protection. In order to reduce indoor radon concentration, the construction department should avoid areas with high radon content and try to choose building materials with low radon content when building new houses. Marketers need to show the radioactive level detection certificate to customers when selling building materials. Residents should pay attention to choosing decorative materials with low radon content when decorating their houses. Increasing indoor ventilation is the most convenient and effective measure to reduce radon. When the doors and windows are opened, the indoor radon and its daughters concentration is roughly equivalent to the external environment. Especially in winter, people close doors and windows in order to keep out the wind and cold, and install air conditioners in order to avoid the summer, which often makes the room a closed space, leading to the gradual accumulation of indoor radon and rising concentration. Therefore, it is particularly important to often open the window for ventilation in summer.
For families with high radon concentration, there are also simple and easy remedial measures.
Ventilation is the most commonly used method to reduce radon concentration. Take a house in Guangzhou as an example. After the doors and windows were closed overnight, the radon concentration was 15 1 m3 baker, and after opening the window for ventilation 1 hour, it was reduced to 48 m3 baker. For the basement, the ventilation problem should also be solved, and the walls and floors should be covered with dense materials or radon-proof coatings to prevent the spread of radon. The subway is a good example. Reporters and experts tested in subways in Beijing and Guangzhou respectively, and the radon concentration was very low, ranging from 17 to 54 cubic meters of Baker. This is because the inner wall of the subway is covered with low-radioactivity, dense materials and has a strong ventilation system.
For families living in bungalows or bungalows, indoor ground gaps should be sealed; Measures such as installing exhaust fans and using air fresheners can also be taken to reduce radon concentration.
4. What are the sources of indoor radon?
Radon separated from building materials; Radon separated from the bottom soil; Radon enters the room from outdoor air due to ventilation; Radon released from water and natural gas used for heating and kitchen equipment.
5. Are building ceramics radioactive?
Radioactive pollution is almost everywhere in modern cities, and people's consumer goods such as glass, ceramics and building materials all contain radioactive substances to varying degrees. Building ceramics are mainly made of clay, sand, slag or industrial waste residue and some natural additives through molding, glazing and sintering. Because of the different geological history and formation conditions, these substances contain radioactive elements, such as thorium, radium, potassium and so on. Especially a quot；; The glaze contains highly radioactive zirconium indium sand. Although the firing temperature of building ceramics is mostly1100 ~1300℃, the radioactivity of these substances cannot be eliminated. Its radioactivity depends on the radioactivity in materials and glazes, and the radioactivity of various tiles varies from place to place.
6. What are the radioactive hazards of building ceramics?
As we all know, radioactive substances widely exist in geological strata and do some harm to human body. Our body's tolerance to radioactivity is limited. If it is excessive, it may cause discomfort and pathological changes. Therefore, radioactive substances exceeding a certain standard will definitely cause harm. Studies have proved that excessive radioactivity in building decoration materials directly affects the health of consumers, especially children, the elderly and pregnant women.
There are two main radioactive hazards of building materials, namely, internal radiation and external radiation. Internal radiation mainly comes from the decay of radioactive radiation in the air, forming radioactive material radon and its daughters. Radon is the only natural radioactive gas in nature. When it acts on the human body, it will rapidly decay into a nuclide that can be absorbed by the human body and enter the human respiratory system to cause radiation damage and induce lung cancer. Statistics show that radon has become the main cause of lung cancer. In the United States, 5000 ~ 20000 people die of radon every year, and in China, about 50000 people die of lung cancer caused by radon and its daughters every year. In addition, radon has a high affinity for human fat, which affects people's nervous system and makes people feel depressed and sleepy. External radiation mainly refers to a biological effect produced by the radiator in natural stone directly irradiating human body, which will cause damage to hematopoietic organs, nervous system, reproductive system and digestive system in human body.
7. How can consumers protect themselves from radioactive substances in construction and decoration?
In the decoration of office buildings and families, it is necessary to reasonably match and make decorative materials, and it is best not to use a decorative material in a large area in the room.
In order to prevent the indoor radioactive substances from being too high, it is best to carry out radioactive background detection before the renovation of new houses, which is helpful to the selection of stone and brick varieties.
When buying stone and building ceramics products in the building materials market, you should ask the dealer for the radioactive test report of the products, and pay attention to whether the report is original, whether the name of the merchant in the report is consistent with the name of the purchased product, and the test results category (A, B, C).
For products such as stone and ceramic tiles that have not been tested by merchants, the best way is to ask experts to conduct radioactive testing with advanced instruments before deciding whether to buy them.
8. How to simply judge the radioactivity of stones?
Generally speaking, stone is divided into marble and granite, and marble is less radioactive than granite. According to the color of the stone, we can simply judge the intensity of radiation. Red, green and crimson are beyond the standard, such as azalea red, Indian red, maple leaf red and rose red.
(3) Types of biological pollutants in indoor environment
Biological pollution can be divided into four categories: first, mold is the main cause of allergic diseases; The second is the pollen of plants; Third, bacteria and viruses carried by human body, animals, soil and plant debris; Fourth, dust mites and hair and dander falling off cats, dogs and birds.
Although air is not a natural environment for the generation and growth of microorganisms-because it does not provide enough water and available nutrients for the growth of bacteria and other microorganisms-higher animals such as human beings are important sources of pollution. Gases discharged in the process of human metabolism, and bad smells emitted by human skin, organs and unclean clothes become odor pollution sources. Living in an odorous environment for a long time is a malignant stimulus to human cerebral cortex, which will make people feel sick, dizzy, tired and lose appetite. Due to people's production and living activities, some microorganisms, including some pathogenic microorganisms, can exist in the air and cause the spread of diseases through the air. Indoor air, especially in poorly ventilated and crowded environments, can contain more microorganisms. In addition to some primitive microorganisms in the atmosphere (non-pathogenic saprophytic microorganisms, Bacillus, achromobacter, micrococcus and some actinomycetes, yeasts and fungi, etc. ), there may also be some pathogenic microorganisms from human body (such as tuberculosis, diphtheria, hemolytic streptococcus, staphylococcus aureus, meningococcus, cold virus, measles virus, etc. ), may become the pathogen of airborne diseases. Generally, the total number of bacteria in indoor air is much higher than that in outdoor air, and the number of bacteria in the air varies greatly in buildings with different uses and rooms with different population densities. Some ornamental plants planted indoors will produce plant fibers, pollen and spores, and allergic people will have asthma and rash. The dander of some pets kept indoors and some microorganisms such as bacteria, viruses, fungi, spores and molds are scattered in the air, which become the media for spreading diseases. In addition, due to the water stored in the air conditioner and the appropriate temperature, it will become a breeding ground for some bacteria, molds and viruses. It is found that bacteria and fungi in air conditioning can induce or aggravate allergic reaction of respiratory system and cause asthma.