The first category - chemical pollution: mainly from decoration, furniture, toys, gas water heaters, insecticidal sprays, cosmetics, smoking, kitchen fumes, etc.;
The second category - physical pollution. Physical pollution: mainly from outdoor and indoor electrical equipment generated by the noise, light and building decoration materials generated by radioactive pollution, etc.;
The third category - biological pollution: mainly from parasitic indoor decoration materials, household goods and air conditioning produced by mites and other bacteria.
These harmful substances interact with each other will aggravate the harm of indoor pollution to people's health, such as indoor air chemical pollution will produce irritation and inflammation of people's skin mucosa and conjunctiva, and even paralyze the respiratory tract cilia and damage to mucosal epithelial tissues, in which case the human body's resistance to disease will be greatly weakened so that pathogenic microorganisms are easy to invade and cause harm to people's health. Therefore, people should pay attention to the indoor environmental pollution, especially the new house and the newly renovated home more attention.
(I), the indoor environment, chemical pollutants and sources
Chemical pollutants in the indoor environment are: formaldehyde, benzene, toluene, xylene, ammonia, sulfur dioxide, nitrogen dioxide, carbon monoxide, carbon dioxide, total volatile organic compounds TVOC and inhalable particulate matter.
1, the source of formaldehyde in the indoor environment and what are the hazards?
Formaldehyde is a colorful, irritating and water-soluble gas. It has the role of protein coagulation, its concentration of 35% to 40% of the aqueous solution commonly known as formalin, often used as a solution for impregnation of specimens. Formaldehyde in the indoor environment from its source can be broadly divided into two categories:
1)Pollution from outdoor air: industrial exhaust, automobile exhaust, photochemical smog, etc. to a certain extent can be discharged or produce a certain amount of formaldehyde, but this part of the content is very small. According to relevant reports show that the annual average concentration of formaldehyde in urban air 0.005 ~ 0.Olmg / m3, generally no more than 0.03mg / m3, this part of the gas at some point in time can be indoors, is a source of indoor formaldehyde pollution.
2)Pollution from the interior itself: formaldehyde mainly from man-made wood panels, mainly used in the production; decoration materials and new combination of furniture is the main source of formaldehyde contamination; decoration materials and furniture in the plywood, large core boards, medium-fiber boards, particle boards (chipboard) adhesive heat, moisture dissolution of formaldehyde is released, the most important indoor formaldehyde release source; UF foam as a Housing heat, cold insulation, foam aging under the action of light and heat; formaldehyde as a preservative paint, chemical fiber carpets, cosmetics and other products; indoor smoking.
So, in general, the source of formaldehyde in the indoor environment is still very wide, generally newly renovated house its formaldehyde content can exceed the standard more than 6 times, individual may exceed the standard up to 40 times. Research has shown that formaldehyde content in the indoor environment and the use of housing time, temperature, humidity and ventilation of the house has a close relationship. In general, the longer the use of housing, the less formaldehyde residue in the indoor environment; the higher the temperature, the greater the humidity, the more conducive to the release of formaldehyde; the better the ventilation conditions, the more conducive to the release of formaldehyde in the construction and decoration materials.
The measured data show that, in general, under normal decoration, the concentration of formaldehyde can be lower than 0.1 mg/m3 after 5 months of indoor decoration; it can be reduced to below 0.08 mg/m3 after 7 months of decoration. The release period of indoor formaldehyde will last for several years.
Formaldehyde has been identified by the World Health Organization as a carcinogenic and teratogenic substance, a recognized source of metamorphic reactions and one of the potentially strong mutagens.
Research has shown that formaldehyde has strong carcinogenic and cancer-promoting effects. It is well documented that the effects of formaldehyde on human health are mainly manifested in olfactory abnormality, irritation, allergy, lung function abnormality, liver function abnormality and immune function abnormality. When its concentration reaches 0.06-0.07mg/m3 per cubic meter of air, mild asthma occurs in children. When the formaldehyde content in indoor air is 0.1mg/m3, there is an odor and discomfort; when it reaches 0.5mg/m3, it can irritate the eyes and cause tears; when it reaches 0.6mg/m3, it can cause throat discomfort or pain. When the concentration is higher, it can cause nausea and vomiting, coughing and chest tightness, shortness of breath and even pulmonary edema; when it reaches 30mg/m3, it will cause immediate death.
Long-term exposure to low doses of formaldehyde can cause chronic respiratory diseases, causing nasopharyngeal cancer, colon cancer, brain tumors, menstrual disorders, genetic mutations in the nucleus, DNA single-stranded internal cross-linking and DNA and protein cross-linking and inhibition of the repair of DNA damage, pregnancy syndromes, causing chromosomal abnormalities in newborns, leukemia, and causing memory and intellectual decline in adolescents. In all contacts, children and pregnant women are particularly sensitive to formaldehyde, the harm is greater.
The World Health Organization (WHO) working group on formaldehyde has stipulated the threshold of its potential carcinogenicity for olfactory, eye irritation and respiratory irritation, and pointed out that when the indoor environmental concentration of formaldehyde exceeds the standard by 10%, adequate attention should be paid.
2, the source of benzene in the indoor environment and what are the hazards?
The source of benzene in the indoor environment is mainly burning tobacco smoke, solvents, paints, colorants, graphic fax machines, computer terminals and printers, adhesives, wallpaper, carpets, synthetic fibers and cleaning agents.
Industry often benzene, toluene, xylene collectively referred to as three benzene, in these three substances to benzene the most toxic.
It is generally believed that benzene toxicity is caused by metabolites, that is to say, benzene has to be metabolized before it can be harmful to life. Benzene can be metabolized in the liver and bone marrow, and bone marrow is the site of formation of red blood cells, white blood cells and platelets, so benzene in the body can be formed in the hematopoietic tissues themselves with hematotoxic metabolites. Long-term exposure to benzene can cause bone marrow and genetic damage, blood test can be found in white blood cells, platelet reduction, whole blood cell reduction and aplastic anemia, and even leukemia. There have been investigations on the health status of workers exposed to low concentrations of benzene, and the results show that: the number of peripheral blood leukocytes is within the normal range, but it is very significantly lower than that of the control group; the distribution of lymphocyte micronucleus rate of workers exposed to benzene is higher than that of the group exposed to non-benzene, and the difference between the lymphocyte micronucleus rate of the benzene production workshop observation group and the comparison of the control group is significant; the number of leukocytes is reduced with the increase of the concentration of benzene in the working environment, and the lymphocyte micronucleus rate tends to decrease. With the increase of benzene concentration in the working environment, the white blood cell count had a tendency to decrease and the lymphocyte micronucleus rate had a tendency to increase. These results show that low concentrations of benzene are detrimental to the health of the working population, with particular attention to the damage to human genetic material.
Inhalation of more than 4000ppm of benzene for a short period of time in addition to mucous membrane and lung irritation, the central nervous system also has an inhibitory effect, accompanied by headache, vomiting, unsteady gait, stupor, convulsions and cardiac arrhythmia.
Inhalation of benzene above 14,000 ppm will cause immediate death.
3. What are the sources and hazards of toluene in the indoor environment?
Toluene mainly comes from some solvents, perfumes, detergents, wallpapers, adhesives, paints, etc. The amount of toluene produced by smoking in the indoor environment is also very considerable. According to the U.S. EPA statistics show that no filter cigarettes, mainstream cigarettes toluene content of about 100 to 200ug, side / mainstream smoke toluene concentration ratio of 1.3.
Toluene into the body after about 48% of the body is metabolized by the liver, brain, lungs and kidneys and finally discharged from the body, in the process of neurological hazards, voluntary experiments to demonstrate that when the blood toluene Volunteer experiment proved that when the concentration of toluene in the blood reaches 1250mg/m3, the short-term memory ability, attention persistence and sensory-motor speed of the exposed person are significantly reduced.
4. What are the sources and hazards of xylene in the indoor environment?
Xylene comes from solvents, pesticides, polyester fibers, tapes, adhesives, wallpaper, paints, wet-processing photocopiers, pressboards, manufactured products and carpets.
Xylene consists of three isomers: neighboring, intermediate, and para, with the intermediate being the largest, up to 60%-70%, and the para being the lowest. Xylene can be absorbed through the respiratory tract, skin and digestive tract, its vapor into the human body through the respiratory tract, part of the respiratory tract discharge, the distribution of absorbed xylene in the body to the adipose tissue and adrenal glands in the most, followed by the bone marrow, brain, blood, kidneys and liver. The toxicity of the three isomers of industrial xylene varies slightly, but they are all of low toxicity. It has been reported that three workers inhaled xylene at a concentration of 43.1 g/m3, one died 18.5 hours later, with pulmonary bruising and cerebral hemorrhage seen on autopsy, and the other two workers were unconscious for 19 to 24 hours, with memory loss and altered renal function. In addition, inhalation of xylene in high concentrations can cause loss of appetite, nausea, vomiting and abdominal pain, and can sometimes cause reversible damage to the liver and kidneys. At the same time, xylene is also an anesthetic, long-term exposure can make the nervous system dysfunction.
5, the main sources of ammonia in the indoor environment and what are the hazards?
In the northern region of China, the construction of residential buildings, office buildings, hotels, restaurants and other building construction, often artificially in the concrete to add high alkali concrete expansion agent and urea-containing concrete antifreeze and other additives to prevent the concrete from freezing and cracking in the winter when the construction, greatly improving the construction progress. These additives containing a large number of ammonia-like substances in the wall with the humidity, temperature and other environmental factors and reduced to ammonia slowly released from the wall, resulting in a large increase in the concentration of ammonia in the indoor air.
Meanwhile, ammonia in indoor air can also come from indoor decorative materials, such as furniture finishing using additives and whitening agents most of which use ammonia. Ammonia is also used in shampoos and beauty salons as a neutralizing agent during perms.
In addition, with the deepening of people's understanding of the destruction of the ozone layer by chlorofluorocarbons, the use of chlorofluorocarbons as refrigerants has been banned worldwide. Ammonia, a refrigerant that has been in use for a century and a half, is being utilized again, having once withdrawn from its position as the dominant refrigerant. It is also a potential source of pollution.
Ammonia belongs to the low-toxicity class of compounds according to toxicology. Ammonia is a colorless gas with a strong irritating odor only when it reaches a certain concentration in the ambient air. The olfactory threshold of ammonia is 0.5-1.0mg/m3. Ammonia is a kind of alkaline substance, which can absorb water in tissues after entering the human body, with high solubility, and it has irritating and corrosive effects on the upper respiratory tract of the human body, and weakens the human body's resistance to diseases. When ammonia enters the alveoli, it is easy to combine with hemoglobin to destroy the oxygen transport function. Inhalation of large amounts of ammonia in the short term can result in tearing, sore throat, hoarseness, coughing, dizziness, nausea, and other symptoms, and in severe cases, pulmonary edema or respiratory distress syndrome, as well as respiratory tract irritation. The American Association of Manufacturing Chemists states that staff are allowed to work at ammonia concentrations below 1 mppn for 8 hours.
6, what are the sources and hazards of sulfur dioxide in the indoor environment?
Sulfur dioxide is a colorless gas with a strong pungent and irritating odor, sulfur dioxide pollution of the indoor environment with the family cooking mode, ventilation, indoor structure and fuel weight related to the majority of farmers in rural areas of our country to burn coal cakes, coal briquettes and honeycomb coal-based, due to the irrational structure of the stove, the coal can not be fully combusted, the emission of a large number of pollutants, which are dominated by sulfur dioxide, the process of smoking Sulfur dioxide will also be produced in the smoking process. There have been studies showing that the sulfur dioxide content in the indoor air of coal-burning households is much higher than that of gas-burning households, and in winter, the kitchen can be up to 0.86mg/m3, and the bedroom can be up to 0.50mg/m3.
Sulfur dioxide acts on the target cells of the upper respiratory tract because it is easily soluble in water to form sulfurous acid to stimulate the mucous membranes of the eyes and the nose and is corrosive; sulfur dioxide is very soluble in the tissue fluids so the inhalation of sulfur dioxide will soon dissolve in air, and it will be very easy for the inhalation to be effective. Sulfur dioxide in the air will soon dissolve and disappear in the upper respiratory tract, rarely into the deep airways, so only deep breathing or sulfur dioxide adsorption on the surface of dust particles may enter the lungs.
Long-term exposure to sulfur dioxide, on the one hand, stimulate the upper respiratory tract caused by bronchial smooth muscle reflex contraction, increased respiratory resistance, respiratory function decline; on the other hand, stimulation and loss of mucous membranes, so that the mucous membrane secretion increased thickening, cilia movement is impeded, the immune function is weakened, resulting in decreased respiratory resistance, induced varying degrees of inflammation, such as chronic nasopharyngitis, chronic bronchitis, bronchial asthma and emphysema. In addition, long-term exposure to sulfur dioxide on the cerebral cortex function has an adverse effect on the brain, so that the brain labor capacity decline, is not conducive to the intellectual development of children.
7. What are the sources of nitrogen dioxide in the indoor environment?
Often referred to as nitrogen oxides are nitrogen monoxide and nitrogen dioxide, nitrogen monoxide in the air is easily converted to nitrogen dioxide. Nitrogen oxides in the indoor environment is mainly due to the combustion of fuel in the cooking and heating process, in addition to smoking can also produce nitrogen oxides. China's urban household fuels are mainly coal, including raw coal and coal, accounting for about 50% to 80% of the total fuel, followed by gas and liquefied petroleum gas, accounting for about 20% to 50%. Most of the rural areas are dominated by coal and biofuels.
Some studies have shown that the average daily concentration of nitrogen oxides in the air of kitchens and bedrooms burning raw coal in winter is 0.159mg/m3, 0.132mg/m3, the average daily concentration of nitrogen oxides in the air of kitchens and bedrooms of users burning coal gas is 0.091mg/m3, 0.078mg/m3, and the average daily concentration of nitrogen oxides in the air of users burning liquefied petroleum gas is 0.070mg/m3, 0.064mg/m3, 0.064mg/m3 and 0.070mg/m3, respectively. The average daily concentrations of NOx from the use of all three fuels were lower in summer than in winter. Therefore the generation of NOx in the 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 the indoor environment?
The main sources of carbon monoxide in the indoor environment are people smoking, heating equipment and kitchens. A cigarette usually produces about 13mg of carbon monoxide, but the amount of carbon monoxide produced is relatively small in the case of a highly breathable cigarette paper, which encourages the complete combustion of cigarettes. Carbon monoxide from heating appliances and kitchens is mainly caused by incomplete combustion of fuel.
9. What are the sources of carbon dioxide in the indoor environment?
Indoor air carbon dioxide in the 0.07% or less belongs to the clean air, the human body feels good; when the concentration of 0.07% to 0.1% belongs to the ordinary air, individual sensitive people will feel the bad smell; in the 0.1% to 0.15% belongs to the critical air, indoor air, other symptoms began to deteriorate, the human body began to feel uncomfortable; to reach 0.15% to 0.2% when belongs to the clear degree of pollution, more than 0.2% belongs to the serious pollution; in 0.3% to 0.4% of people breathing deeper, headache, tinnitus, blood pressure increase and other symptoms when it reaches 0.8% or more will cause death.
10, the indoor environment of the inhalable particulate matter what?
Resorbable particulate matter (Particular matter less than 10 un, PM 10): refers to particulate matter suspended in the air, the aerodynamic equivalent diameter (10 micron). Airborne particulate matter comes from a wide range of sources, dust, bacteria, hair, dandruff, wall lice, dust, smoke and airborne hazardous substances and respirable particulate matter combine to form a very harmful allergen.
11, volatile organic pollutants (VOCs) in the indoor environment, what are the classification and sources?
Volatile organic pollutants are divided into four categories: extremely volatile organic compounds (VVOCs), volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs) and particulate matter or particulate organic matter related to organic matter (POM), and in the detection of organic pollutants in the indoor VOCs basically represent the state of pollution of the organic matter. 1989 the U.S. Environmental Protection Agency layer detected the presence of more than 900 kinds of organic matter. Environmental Protection Agency layer detected more than 900 kinds of VOCs present indoors.
The sources of VOCs in the indoor environment are mainly released from building materials, cleaning agents, paints, water-containing paints, adhesives, cosmetics, and detergents, etc., in addition to smoking and cooking processes.
The common indoor VOCs listed in the 1984 World Health Organization report "Awareness of Concerns Regarding Indoor Air Pollutants***" are listed in the following table:
Pollutants
Sources
Formaldehyde
Insecticides, pressed-board manufactured products, urea-formaldehyde foam insulation ( UFFI), hardwood plywood, adhesives, particle board, laminates, paints, plastics, carpeting, soft plastic furniture covers, gypsum board, jointing compounds, ceiling tiles and siding, non-latex inlay compounds, acid-cured wood coatings, wood siding, plastic/cyanoacrylamide siding, vinyl (plastic) tiles, parquet
Benzene
Indoor smoke from burning tobacco, solvents Paint, stain, varnish, graphic fax machines, computer terminals and printers, jointing compounds, latex inlays, water-based adhesives, wood siding, carpet, tile adhesives, stain/textile cleaners, polystyrene foam, plastics, synthetic fibers
Carbon tetrachloride
Solvents, refrigerants, aerosol sprays, fire extinguishers, solvents for grease
Trichloroethylene
Solvents, dry-cleaned fabrics, upholstery covers, inks, paints, lacquers, varnishes, adhesives, graphic faxes, computer terminals and printers, typewriter correction fluids, paint removers, stain removers
Perchloroethylene
Dry-cleaned fabrics, upholstery covers, stain/textile cleaners, graphic faxes, computer terminals and printers
Tetrachloroethylene
Dry-cleaned fabrics, upholstery covers, stain/textile cleaners, graphic faxes, computer terminals and printers
Chloroform
Solvents, dyes, decontaminants, graphic faxes, computer terminals and printers, upholstery cushions, chloroform water
1,2-dichlorobenzene
Dry-cleaning additives, grease removers, pesticides, carpet
1,3- Dichlorobenzene
Insecticides
1,4-Dichlorobenzene
Deodorizers, mold and mildew removers, air fresheners/deodorizers, deodorizers for toilets and wastebaskets, deodorant pills and tablets
Ethylbenzene
Styrene-related manufactured products, synthetic polymers, solvents, graphic and printers, polyurethanes, furniture polish, jointing compounds, latex and non-latex jointing compounds, tile adhesives, carpet adhesives, varnished hardwood parquet
Toluene
Solvents, perfumes, detergents, dyes, water-based adhesives, sealers, molding tapes, wallpaper, jointing compounds, silicate sheeting, vinyl (plastic) coated wallpaper, jointing compounds, Paints, Carpets, Presswood Trim, Vinyl (Plastic) Tiles, Paints (Latex and Solvent-Based), Carpet Adhesives, Grease Solvents
Xylene
Solvents, Dyes, Insecticides, Polyester Fibers, Adhesives, Joining Compounds, Wallpaper, Seam Sealing Compounds, Varnishes, Resin and Ceramic Paints, Carpets, Wet Processing Photocopiers, Laminated Manufactured Goods, Gypsum Board, Water-Based Adhesives, Grease solvents, paints, carpet adhesives, vinyl (plastic) tiles, polyurethane coatings
(2) Radioactive contamination and hazards in the indoor environment
1. What are the sources of natural radioactivity?
There are many varieties of natural radionuclides, with different properties and states, and they are widely distributed in the environment. There are traces of natural radionuclides in rocks, soil, air, water, plants and animals, building materials, food and even people. The Earth's crust is an important reservoir of natural radionuclides, especially primary radionuclides. The radioactive materials in the earth's crust are mainly uranium, thorium systems and. Among them, the natural radionuclides in the air are mainly surface released into the atmosphere and its substrate nuclides, most of the natural radionuclides in animal and plant food.
Soil is mainly produced by the erosion and weathering of rocks, it can be seen that the radioactivity in it is transferred from the rocks. Since there are many types of rocks, which are subjected to natural conditions to varying degrees, it can be expected that the range of variation in the concentration of natural radionuclides in soil is large. The geographic location of the soil, its geologic origin, hydrologic conditions, climate, and agricultural history are all important factors that influence the amount of natural radionuclides in the soil.
Radioactive materials present in rocks and soils are subject to loss due to leaching and filtration by groundwater, the main pathway from which natural radionuclides in groundwater originate. In addition, radionuclides adhering to surface particles of soil can be converted into dust or aerosols under the action of wind, which can then be transferred to the atmosphere and further transported to plants or animals. Some soluble radionuclides in soil are absorbed by plant roots, then transported to edible parts, then taken up by herbivores, then transferred to carnivores, and ultimately become one of the important sources of radionuclides in food and in humans. The concentration of naturally occurring radionuclides in environmental water is related to a number of factors.
In addition, naturally occurring radioactive substances include cosmic rays. Cosmic rays are a stream of high-energy particles that are shot from cosmic space to the earth, which consists of protons, particles, and so on. Natural radioactivity has been adapted by humans and has not caused much harm.
2. What is the harm of radon to human body?
Radon enters the human body through breathing, and the short-lived radionuclides produced during the decay will be deposited in the bronchial tubes, lungs and kidney tissues. When these short-lived radionuclides decay, the particles released are the most damaging to internal irradiation, which can expose the epithelial cells of the respiratory system to radiation. Long-term internal irradiation may cause local tissue damage and even induce lung and bronchial cancers. It is estimated that during a person's lifetime, if he lives in a room environment with a radon concentration of 370Bq/m3, 30-120 people per thousand will die of lung cancer. Radon and its daughters will also emit highly penetrating rays when decaying, causing external irradiation to the human body.
If one lives in an environment with high radon content for a long time, it may cause harm to one's circulatory system, such as the reduction of white blood cells and platelets, which may also lead to leukemia in serious cases.
This kind of harm is a heavy lesson: in 1922, Egypt, a number of Egyptian archaeologists to excavate the ancient Egyptian Dutang Kamen Pharaoh's mausoleum, followed by strange deaths, and since then the Pharaoh's poisonous spell that has been spreading, and the people are said to be the ancient Egyptian pyramid under the poisonous spell, so that trespassing into the pyramid of the poisonous spell and sentenced to death. Recently, Canada and Egypt's indoor environment experts cracked this plagued people nearly rib years of the mystery of the poison spell. They found that the pyramid contains a large amount of dangerous radon gas, which causes lung cancer and death of those who come into contact with it. The experts found that the deadly radon gas was released from the decayed uranium contained in the stones and soil of the building pyramids. The three ancient Egyptian buildings that contain the highest levels of radon are, in order, the pyramids of Shakamkat, south of Cairo, the Abis Tunnel and the mausoleum of Sarabiyum. Baxter, an indoor environment expert, said, "It was the high levels of radon gas that damaged the health of Egyptian archaeologists back then."
3. How to prevent the harm of radon to human body?
Since the harm of radon is accumulated over a long period of time and is not easy to be detected, it is necessary to pay great attention to it and do a good job in publicizing and popularizing radon and its protection. In order to reduce the concentration of radon indoors, the construction department should avoid lots with high radon content when building new houses and choose building materials with low radon content as far as possible. Marketers are required to show customers the certificate of radioactivity level testing when selling building materials. Residents should pay attention to choosing decorative materials with low radon content when carrying out home decoration. Increasing indoor ventilation is the most convenient and effective radon reduction measure. When doors and windows are open, the concentration of indoor radon and its daughters is roughly equal to that in the external environment. Especially in winter, people close their doors and windows to avoid wind and cold, and install air-conditioning in summer to avoid summer heat, which makes the living room often created as a closed space, resulting in the gradual accumulation of indoor radon and a rise in its concentration, so it is especially important to frequently open the windows for ventilation in summer.
There are also simple and easy remedial measures for families with high radon concentration.
The most common way to reduce radon concentration is ventilation. For example, in a house in Guangzhou, the radon concentration is 151 cubic meters of Beck after the windows and doors are closed for one night, and it has been reduced to 48 cubic meters of Beck after the windows are opened for one hour. For basements, the problem of ventilation should also be solved and the walls and floors should be covered with dense materials or radon resistant paint to block the spread of radon. A good example here is the subway. Reporters and experts have tested the subways in Beijing and Guangzhou respectively, and the radon concentration is very low, ranging from 17 to 54 cubic meters of Bq. This is because the walls of the subway are covered with materials with low radioactivity and dense texture, coupled with a strong ventilation system.
Families living in bungalows or one-storey houses should plug and seal the gaps on the floor indoors; measures such as installing exhaust fans and using air fresheners can also be used to reduce the concentration of radon.
4. What are the sources of indoor radon?
Radon precipitated from building materials; radon precipitated from subsoil; radon entering indoor from outdoor air due to ventilation; radon released from water supply and natural gas used for heating and kitchen equipment.
5, building ceramics are radioactive?
Radioactive pollution is almost everywhere in the modern city, and there are different degrees of radioactive substances in consumer products such as glass, ceramics and building materials. Building ceramics is mainly from clay, sand, slag or industrial waste and some natural materials such as molding and glaze by sintering. Due to the geological history of these materials and the formation of different conditions, more or less the presence of radioactive elements, such as thorium, radium, potassium, etc.. In particular, the surface of building ceramics a "quot; glaze", containing high radioactivity of zirconium indium sand, although most of the firing temperature of building ceramics in 1100 ~ 1300 ℃, but can not eliminate the radioactivity of these substances, the radioactivity of its high and low decision on the material and glaze in the radioactivity, and around the varieties of ceramic tiles There are differences in radioactivity.
6, building ceramics, what are the hazards of radioactivity?
It is well known that radioactive substances are widely present in the geological layer, the human body has a certain degree of harm. Our body's ability to withstand radioactivity has a certain limit, excessive may cause discomfort and lesions. Therefore, radioactive substances exceeding a certain standard will definitely cause harm. Research has proved that the building decoration materials radioactive exceeds the standard, directly affect the consumers, especially children, the elderly and pregnant women's health.
There are two main aspects of radioactive hazards in building materials, namely, in vivo radiation and in vitro radiation: in vivo radiation mainly comes from the decay of radioactive radiation in the air, and the formation of a radioactive substance radon and its substrates. Radon is the only natural radioactive gas in nature. Radon acts on the human body while it will soon decline into nuclides that can be absorbed by the human body and enter the human respiratory system causing radiation damage and inducing lung cancer. Statistics show that radon has become the main cause of lung cancer, and the annual deaths in the United States have amounted to 5,000 to 20,000 people, and there are about 50,000 people in our country who died of lung cancer caused by radon and its substrates every year. In addition, radon also has a high affinity for human fat, thus affecting the human nervous system, making people mentally unstable and drowsy. In vitro radiation mainly refers to the natural stone in the radioactive body directly irradiated after the human body to produce a biological effect, will cause damage to the human body's hematopoietic organs, nervous system, reproductive system and digestive system.
7, how can consumers protect themselves from radioactive substances in construction and decoration?
When carrying out office buildings and home decoration, it is necessary to reasonably match and make decorative materials, and it is best not to use a decorative material in a large area of the room.
In order to prevent excessive radioactive substances in the room, it is best to carry out the radioactive background of the test before the renovation of the new housing, which will help the choice of stone and through the brick varieties.
To the building materials market to buy stone and building ceramics products, to the dealer to ask for product radioactivity test report, pay attention to whether the report is the original, the report of the business name and the name of the product purchased whether it is consistent, in addition to the category of test results (A, B, C).
The merchants do not have test reports of stone and tile products, the best way is to ask the experts to use advanced equipment to detect radioactivity, and then decide whether to buy.
8, how to simply determine the stone radioactivity?
Generally speaking, stone is divided into marble, granite, marble radioactivity is smaller than granite. Can be based on the color of the stone can be simple to determine the strength of the radiation, red, green, crimson exceeds the standard more, such as azalea red, Indian red, maple red, rose red, etc. exceeds the standard more.
(C), the indoor environment biological pollutants
Bio-pollution can be divided into four categories: one is mold, which is the most important cause of allergic diseases; two is from the pollen of plants; three is by the human body, animals, soil and plant debris carried by bacteria and viruses; and four dust mites, as well as cats, dogs and birds shedding hair, dander.
While air is not a natural environment for the production and growth of microorganisms - because it does not provide enough moisture and available forms of nutrients needed for the growth of bacteria and other microorganisms - man, a higher animal, is an important source of pollution. The gases emitted during human metabolism and the bad odors emitted from human skin, organs and unclean clothing become the source of odor pollution. Prolonged living in the odor environment, the human cerebral cortex is a vicious stimulation, will make people nausea, dizziness, fatigue and loss of appetite. Due to people's production and living activities, certain 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, crowded environments, can have more microorganisms. In addition to some microorganisms in the atmosphere (non-pathogenic saprophytic microorganisms, Bacillus spp., Bacillus spp., Bacillus spp., Bacillus spp., and some actinomycetes, yeasts, and fungi, etc.), some pathogenic microorganisms (such as Mycobacterium tuberculosis, Mycobacterium diphtheriae, Streptococcus haemolyticus, Staphylococcus aureus, Meningococcus spp., influenza viruses, and measles viruses, etc.), which may become the pathogenic agents of airborne diseases. pathogens of airborne diseases. The total number of bacteria in indoor air is generally much higher than that in outdoor air, and the number of airborne bacteria varies considerably in the interiors of buildings with different purposes and population densities. Some ornamental plants grown indoors produce plant fibers, pollen and cysts, which can cause asthma and rashes in allergic persons. The dander of some pets kept indoors as well as some microorganisms such as bacteria, viruses, fungi, bacilli, molds, etc. are scattered in the air and become a medium for spreading diseases. In addition, because of the air conditioning unit water storage and the temperature is suitable, will become some bacteria, mold, viruses breeding habitat. Studies have found that bacteria and fungi in air conditioners can induce or exacerbate allergic reactions in the respiratory system and cause asthma.