The following points highlight the ten major contaminants of indoor air. The contaminants are: 1. Biological Contaminants and Health Effects 2. Radon 3. Formaldehyde 4. Polychlorinated Biphenyls (PCBs) 5. Tobacco Smoke 6. Volatile Organic Compounds (VOCs) 7. Stoves, Heaters, Fireplaces and Chimneys 8. Household Products 9. Pesticides 10. Electro-Magnetic Pollution.
1. Biological Contaminants and Health Effects:
Bacteria, viruses, fungi, pollens, house dust, and mite droppings are found in indoor air. Fungi, including spores and moulds, multiply in the presence of increased humidity level (greater than 60 per cent). Pollens, fungi and other allergens are also brought indoors by ventilation systems, clothing, tracking and open doors and windows.
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Substantial reduction in ventilation rates will tend to increase concentrations of contaminants and the probability of infection and allergy to the extent contaminants remain viable and airborne. Sources of biological contaminants include air-conditioning systems; humidifiers; air ducts; cooling towers; grass, tree and weed pollens; occupants; and household pets. Keep air-conditioning systems clean and empty, clean humidifiers and sanitise frequently and minimise household dust.
Some unit air cleaners are effective in removing particulates but may also incubate fungi and micro-organisms. Air cleaners, such as electrostatic precipitators, ionisers or filters, are not designed to remove radon or other gases. Humidifiers and filters require scheduled cleaning or filter replacement. Prevent the accumulation of water in equipment; ensure proper drainage. Recirculating or independent steam humidification is said to be preferable to the filter-type humidifier for room humidification. Ensure that the water used is not contaminated with toxic volatile compounds.
The spread of respiratory diseases is facilitated by infectious agents and particulates in contaminated air. Overcrowding and the recirculation of contaminated air, if not adequately diluted, cleaned or disinfected, permit continual seeding and accumulation of pathogenic micro-organisms at a rate exceeding the natural die-off rate. A study at US Army training centers showed a 45 per cent increase in respiratory infection in energy-efficient buildings providing 1.8 ft3 per minute per person outside air.
This was compared to older barracks providing 14.4 ft3 per minute per person outside air where the infection rate was lower. Legionnaire’s disease, meningococcal meningitis, the common cold, influenza and other respiratory diseases, may be transmitted by airborne aerosols. Comprehensive studies on the health effects of long and short-term exposure to indoor (and outdoor) contaminants are limited.
Young children, the elderly, and people suffering from respiratory diseases will be the first to show signs of discomfort from indoor air contamination. Some common complaints are headache; fatigue; eye, nose and throat irritation; fever; and dizziness.
The following steps can reduce exposure to biological contaminants in the home:
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i. Install and Use Exhaust Fans that are vented to the Outdoors in Kitchens and Bathrooms and Vent Clothes Dryers Outdoors:
These actions can eliminate much of the moisture that builds up from everyday activities. There are exhaust fans which produce little noise, an important consideration for some people. Another benefit to using kitchen and bathroom exhaust fans is that they can reduce levels of organic pollutants that vapourise from hot water used in showers and dishwashers.
ii. Ventilate the Attic and Crawl Spaces to Prevent Moisture Buildup:
Keeping humidity levels in these areas between 30-50 per cent can prevent water condensation on building materials.
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iii. If Using Cool Mist or Ultrasonic Humidifiers, Clean Water Trays and Fill With Fresh, Distilled Water Daily:
Because these humidifiers can become breeding grounds for biological contaminants, they have the potential for causing diseases such as hypersensitivity pneumonitis. Evaporation trays in air conditioners, dehumidifiers and refrigerators should also be cleaned frequently.
iv. Thoroughly Dry and Clean Water-Damaged Carpets and Building Materials (Within 24 Hours if Possible):
Water-damaged carpets and building materials can harbour mould and bacteria. If health problems persist after you have tried to dry these materials, consider replacing them. It can be very difficult to completely rid such materials of biological contaminants.
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v. Keep the House Clean:
House dust mites, pollens, animal dander and other allergy-causing agents can be reduced, although not eliminated, through regular cleaning. People who are allergic to these pollutants should not vacuum (and may even need to leave the house while vacuuming is occurring), because vacuuming can actually increase levels of airborne mite allergens and other biological contaminants. Using central vacuum systems that are vented to the outdoor may reduce allergic reactions to biologicals.
6. Take Steps to Minimise Biological Pollutants in Basements:
Clean and disinfect the basement floor drain regularly. Do not finish a sub-surface basement unless all water leaks are patched and outdoor ventilation and adequate heat to prevent condensation are provided. Operate a dehumidifier in the basement if needed to keep relative humidity levels between 30-50 per cent.
2. Radon:
Radon is an odourless, colourless and tasteless chemically inert radio-active gas released in the decay of radium from uranium in most soils and rocks. It is found naturally in soil gas, underground water and outdoor air. It is 60 times more soluble [at 50°F (10°C)] than oxygen in water. Radon has a half-life of 3.8 days.
Thorium, one of the uranium decay products, also releases radon. Radon and primarily its alpha-emitting decay products (especially polonium) contribute a major portion of the biologically significant dose associated with natural background radiation. The beta and gamma emissions are not significant. The alpha particles, however, adhere to dust particles that, when inhaled, can become attached to the lungs and remain to irradiate the surrounding tissue, contributing to the cause of cancer.
It has been estimated that exposure to ‘one working-level month’ over a lifetime (assumed to be 70 years) would result in about 350 additional lung cancer deaths per million people exposed. It has also been estimated that radon causes 15000 cancer deaths per year. Smokers are at much greater risk. In view of this, a screening programme to identify problem areas and recommend mitigation alternatives to home owners is indicated. Also indicated is radon measurement before the purchase of a new or existing home.
The hazard associated with radon is related to the concentration and time of exposure. Radon should not exceed 2 to 5 pCi/l indoors. The US Environmental Protection Agency (EPA) has set a guideline limit of 4 pCi/l per 24 hours for homes (this is believed to be conservative) and a standard of 20 pCi/l in underground uranium mines. Special problems exist at uranium tailings and phosphate slag sites.
Major potential entry sources of indoor radon from the soil are cracks in dwelling concrete floor slabs and basement walls; pores and cracks in concrete blocks, mortar joints and floor-wall joints; spaces behind brick veneer walls that rest on uncapped hollow-block foundations; floor drains; footing drains; and exposed soil in the bottom of drainage sumps.
Radon-contaminated water, when agitated, aerated, or splashed as in dishwashing, clothes washing, showering, and toilet flushing and opened faucets or when water is heated, permits the release of radon. In addition to rock and soil underlying dwellings, construction materials (some stone masonry, concrete blocks, bricks, concrete) and some well and seepage water and gas supplies may be the source of radium and radon.
In the average dwelling, 10000 pCi/l of radon in the water can be assumed to release 1 pCi/l to the air, but the actual indoor concentration will be dependent primarily on the amount of radon entering from the soil and on the extent to which the indoor air is diluted by outside air.
If the water is high in radon, it can be removed by filtering through a granular activated-carbon (GAC) filter, by storage until the radon has decayed or by aeration before it enters the dwelling water system. But the carbon becomes radio-active and in decay releases gamma radiation, which can be a health hazard.
Aeration appears to be the most cost-effective procedure for public water systems and a GAC filter for a private dwelling having its own well-water supply, if needed. Activated carbon concentrates the radon and decay products and hence, poses a disposal problem.
Radon contamination in an existing dwelling, if it is a problem, can be reduced by preventing its entry or by removing the radon. It can be reduced by closing and caulking all cracks, joints and openings of the structure in the basement or in contact with the ground or in the flooring above the crawl space and by tightly covering open drains and sumps as previously noted.
Good insulation of water pipes and under-flooring beneath living areas would be required in the crawl space in areas subjected to sub- freezing temperatures and to reduce heating or cooling costs. If this is not sufficient to reduce the indoor radon level, natural or mechanical forced-air ventilation into basement and crawl spaces can be provided, with openings to allow radon-laden air to exit. Exhaust ventilation would be needed for tightly covered sumps and footing drains. To reduce radon levels in basements and enclosed crawl spaces, bring in outside air to dilute and displace the inside air.
Forced-air ventilation may be necessary; exhaust fans in living areas and combustion air for warm-air furnaces and fireplaces would depressurise the dwelling and draw in radon from the basement and should not be used. Provide outside air vent for furnace and hot-water gas heater and outside air duct for wood stove and fireplace.
In a new building, the gravel under the basement floor or floor slab could have perforated pipe embedded in it to intercept and vent radon gas above the roof using a mechanical exhaust fan. Wind turbines and natural convection are not effective. A polyethylene sheet would be placed under the basement concrete floor slab above the gravel before it is poured. The ventilation method used must not reduce the air pressure within the dwelling. Sealing major potential sources of radon entry as stated above and ventilation should greatly reduce radon concentrations to ‘safe’ levels in most cases.
The need for radon protection, such as built-in ventilation under the basement floor or floor slab, is best provided in new construction and required in building codes where needed. Local geological information and in-home radon measurements will give an indication of need.
Exposure to Radon in the home can be reduced by the following steps:
1. Measure levels of radon in the home – Two types of radon detectors are most commonly used in homes. Charcoal canisters that are exposed for 2 to 7 days; and alpha track detectors that are exposed for one month or longer. (Some states recommend that residents use only the alpha track monitors).
2. The higher the radon level in the home, the faster action should be taken to reduce exposure. Radon levels in homes can be reduced to about 4 picocuries per liter of air and sometimes less.
3. Learn about control measures – An effective radon mitigation plan may include one or more of the following actions: sealing cracks and other openings in basement floors, ventilating crawl spaces, installing sub-slab or basement ventilation or installing air-to-air heat exchangers.
4. Take precautions not to draw larger amounts of radon into the house. Increasing ventilation can be an effective means of reducing exposure to many indoor air pollutants; in homes with elevated concentrations of radon, however, increasing ventilation may increase infiltration through the foundation and result in drawing even larger amounts of radon into the home. The benefits of increased ventilation can be achieved without increasing radon exposure by opening windows evenly on all sides of the home. Opening windows are particularly important when you are using outdoor-vented exhaust fans.
5. Select a qualified contractor to draw up and implement a radon mitigation plan.
6. Stop smoking, and discourage smoking in your home: Scientific evidence indicates that smoking may increase the risk of cancer associated with exposure to radon.
7. Treat radon-contaminated well water by aerating or filtering through granulated-activated charcoal.
3. Formaldehyde:
Formaldehyde, a colourless gas, may cause extreme discomfort and contact dermatitis indoors. The odour can be detected at less than 1 ppm. Exposure to 1.0 to 5.0 ppm or less can cause burning of the eyes, tearing and general irritation of the upper respiratory passages. Levels of 0.3 to 2.7 ppm have been found to disturb sleep and to be irritating to some persons. Exposure to 10 to 20 ppm may produce coughing, tightening in the chest, a sense of pressure in the head and palpitations.
Exposures of 50 to 100 ppm and above can cause serious injury, including pulmonary edema and pneumonitis, and possibly death when above 100 ppm. Exposure to formaldehyde solutions or urea-formaldehyde-containing resins, is a well-recognised problem. However, a four-year study at the National Cancer Institute in US concluded that there is ‘Little evidence that mortality from cancer is associated with formaldehyde exposure at levels experienced by workers in this study’.
Sources of formaldehyde are resins and glues to bond particle board and plywood, urea-formaldehyde foam insulation, permanent press fabric, embalming fluid, drugs, disinfectants and cosmetics as well as chemicals used in pathology and anatomy laboratories and in the manufacture of automobiles, furniture, paper and electrical equipment. Formaldehyde problems are also related to materials in mobile homes and pre-fabricated housing. Users of formaldehyde should wear protective clothing, use protective equipment, and apply engineering controls such as hoods and separate exhaust systems.
The workplace should provide a minimum ventilation of five air changes per hour. Some ameliorative measures suggested, where urea-formaldehyde is a problem, are to remove the product; seal with a specially formulated coating, vinyl covering, latex paint or varnish after two years; and increase ventilation. Sealing will prevent the penetration of moisture, contact with urea formaldehyde and release of formaldehyde gas.
The gas release from materials tends to decline in time. Improper formulation of urea-formaldehyde foam insulation is believed to exacerbate the problem. It is no longer used in the United States. Phenol- formaldehyde resins are generally used in outdoor materials and do not release significant quantities of formaldehyde; however, they cost more than urea-formaldehyde products.
The Occupational safety and health administration (OSHA) 8 hours time-weighted average occupational exposure has been reduced from 3.0 to 1.0 ppm with a maximum short-term exposure level of 2.0 ppm for any 15 minute period. The National Research Council has established a limit of 0.1 ppm for space flights. The Department of Housing and Urban Development (HUD) has set a limit of 0.4 ppm for indoor air.
The following steps can reduce exposure to formaldehyde in the home:
1. Ask about the formaldehyde content of pressed wood products, including building materials, cabinetry and furniture before purchasing them. If you experience adverse reactions to formaldehyde, you may want to avoid the use of pressed wood products and other formaldehyde- emitting goods. Even if you do not experience such reactions, you may wish to reduce your exposure as much as possible by purchasing exterior-grade products, which emit less formaldehyde.
Some studies suggest that coating pressed wood products with polyurethane may reduce formaldehyde emissions for some period of time. To be effective, any such coating must cover all surfaces and edges and remain intact. Increase the ventilation and carefully follow the manufacturer’s instructions while applying these coatings. If you are sensitive to formaldehyde, check the label contents before purchasing coating products to avoid buying formaldehyde- containing products, as they will emit the chemical for a short time after application.
2. Maintain moderate temperature and humidity levels and provide adequate ventilation. The rate at which formaldehyde is released is accelerated by heat and may also depend somewhat on the humidity level. Therefore, the use of dehumidifiers and air conditioners to control humidity and to maintain a moderate temperature can help reduce formaldehyde emissions. Drain and clean dehumidifier collection trays frequently so that they do not become a breeding ground for micro-organisms. Increasing the rate of ventilation in your home will help in reducing formaldehyde levels.
4. Polychlorinated Biphenyls (PCBs):
PCBs are considered ‘probable’ human carcinogens based on animal studies. Possible major exposure routes to PCBs are inhalation when electrical transformers and other equipment containing PCBs are ruptured or burned, breathing PCB-contaminated air or skin contact in the work environment, the ingestion of food (fish) or drinking water containing PCBs and spills or illegal dumping of fluids containing PCBs. Fluorescent light ballasts and vinyl-coated paper are also a common source of PCBs. It is best to use caution and seek advice immediately from your health or environmental protection department should there be an actual or potential exposure to PCBs.
The Occupational safety and health administration has established an airborne exposure limit of from 0.5 mg/m3 (54 per cent chlorine content) to 1 mg/m3 (42 per cent chlorine content) as an 8 hours time- weighted average (skin). The National Institute of Occupational Safety and Health (NIOSH) recommends that the airborne exposure to PCBs in the workplace be 1 μg/m3 or less. The EPA has proposed a limit of 100 μg/m2 in areas where frequent and regular skin contact with surfaces is possible.
5. Tobacco Smoke:
Environmental tobacco smoke consists of a suspension of 0.01 to 1 μm particles leaving the burning tobacco condensate. Also produced are numerous hazardous gases including carbon monoxide. The involuntary chronic exposure to cigarette smoke, also referred to as passive smoking, is associated with an increased risk of lung cancer according to the National Academy of Science (NAS).
In addition, children of smoking parents have increased respiratory illnesses compared with children whose parents do not smoke. According to the NAS report, passive smoking causes irritation of the eyes, nose, and throat of many non-smokers.
Ventilation rates of up to five times higher in smoking areas are suggested to achieve acceptable indoor air quality. Office spaces should provide at least 20 ft3/min per occupant of clean outside air where smoking is permitted and at least 5 ft3/min per occupant in non-smoking areas. Effort should be directed to the prohibition of smoking in enclosed spaces and the discouragement of smoking.
6. Volatile Organic Compounds (VOCs):
VOCs are a broad range of chemical compounds with boiling points in the range of approximately 120 to 480°F (50-260°C) and vapour pressures greater than about 4 × 10-5 to 4 × 10-6 inch Hg. Several hundred VOCs have been identified in the indoor environment.
The Large Buildings Study by the EPA developed a VOC sample target list that includes aliphatic hydrocarbons, halogenated hydrocarbons and oxygenated hydrocarbons such as aldehydes, alcohols, ketones, esters, ethers and acids. Sources of VOCs in non-industrial environments include building materials, furniture, furnishings, ventilation systems, household and consumer products, office equipment and outdoor-related activities (e.g., traffic, neighbourhood industry).
Little is known about the symptoms of overexposure to VOCs, but some are suspected of causing adverse health effects such as sensory irritation, odour and the more complex set of symptoms of sick- building syndrome. Also researchers have found that neurotoxic effects may follow from low-level exposures to gaseous air pollutants.
Reactions include runny eyes and nose, high frequency of airway infections, asthma-like symptoms among non-asthmatics, along with odour or taste complaints. There is also a possible link between the increase in allergies throughout the industrialised areas of the world and exposure to elevated concentrations of VOCs.
Emission source control, gas-phase air filtration using activated-carbon filters or photocatalytic reactors and ventilation are common ways of controlling indoor VOCs.
7. Stoves, Heaters, Fireplaces and Chimneys:
In addition to environmental tobacco smoke, other sources of combustion products are unvented kerosene and gas space heaters, woodstoves, fireplaces and gas stoves. The major pollutants released from these sources are carbon monoxide, nitrogen dioxide and particles. In addition, woodstoves, fireplaces and unvented kerosene space heaters emit polycyclic aromatic hydrocarbons. Unvented kerosene heaters may also generate acid aerosols.
Other sources of combustion gases and particulates are chimneys and flues that are improperly installed or maintained and cracked furnace heat exchangers. Pollutants from fireplaces and woodstoves with no outside air supply vent can be ‘down-drafted’ from the chimney back into the living space, particularly in ‘weather-tight’ homes.
Carbon monoxide is a colourless, odourless gas that interferes with the delivery of oxygen throughout the body. At low concentrations, it can cause fatigue in healthy people and episodes of increased chest pain in people with chronic heart disease. At higher concentrations, carbon monoxide can cause headaches, dizziness, weakness, nausea, confusion and disorientation.
The symptoms of carbon monoxide poisoning are sometimes confused with the flu or food poisoning. At very high concentrations carbon monoxide can cause unconsciousness and death. Fetuses, infants, pregnant women, elderly people and people with anemia or with a history of heart or respiratory disease can be especially sensitive to carbon monoxide exposures.
Nitrogen dioxide can irritate mucous membranes in the eye, nose and throat and cause shortness of breath after exposure to high concentrations. There is evidence that high concentrations or continued exposure to low levels of nitrogen dioxide can increase the risk of respiratory infection; there is also evidence from animal studies that repeated exposures to elevated nitrogen dioxide levels may lead, or contribute, to the development of lung disease such as emphysema. People at particular risk from exposure to nitrogen dioxide include children and individuals with asthma and other respiratory diseases.
Respirable particles, released when fuels are incompletely burned, can lodge in the lungs and irritate or damage lung tissue. A number of pollutants, including radon and benzo(a)pyrene, both of which can cause cancer, attach to small particles that are inhaled and then carried deep into the lung.
The following steps can reduce exposure to combustion products in the home:
1. Take special precautions when operating fuel-burning unvented space heaters. Consider potential effects of indoor air pollution when you decide to use an unvented kerosene or gas space heater. Follow the manufacturer’s directions, especially instructions on the proper fuel and keeping the heater properly adjusted. A persistent yellow-tipped flame is generally an indicator of maladjustment and increased pollutant emissions. While a space heater is in use, open a door from the room where the heater is located to the rest of the house and open a window slightly.
2. Install and use exhaust fans over gas cooking stoves and ranges and keep the burners properly adjusted. Using a stove hood with a fan vented to the outdoors can greatly reduce exposure to pollutants during cooking. Improper adjustment, often indicated by a persistent yellow-tipped flame, can result in increased pollutant emissions.
Ask the gas company to adjust the burner so that the flame tip is blue. If you purchase a new gas stove or range, consider buying one with pilotless ignition because they do not have a pilot light that burns continuously. Never use a gas stove to heat the home and always make certain the flue in the gas fireplace is open when the fireplace is in use.
3. Keep woodstove emissions to a minimum. Choose properly sized new stoves that are certified as meeting EPA emission standards. Make certain that doors in old woodstoves are tight-fitting. Use aged or cured (dried) wood only and follow the manufacturer’s directions for starting, stoking and putting out the fire in woodstoves. Chemicals are used to pressure-treat wood; such wood should never be burned indoors.
4. Have central air handling systems—including furnaces, flues and chimneys—inspect annually and promptly repair cracks or damaged parts. Blocked, leaking or damaged chimneys or flues can release harmful combustion gases and particles and even fatal concentrations of carbon monoxide.
Strictly follow all service and maintenance procedures recommended by the manufacturer, including those that tell how frequently to change the filters. If the manufacturer’s instructions are not readily available, change filters once every month or two during periods of use. Proper maintenance is important even for new furnaces, because they can also corrode and leak combustion gases, including carbon monoxide.
8. Household Products:
Organic chemicals are widely used as ingredients in household products because of their many useful characteristics, such as the ability to dissolve substances and evaporate quickly. Paints, varnishes and wax all contain organic solvents, as do cleaning, disinfecting, cosmetic, degreasing and hobby products. Fuels are made up of organic chemicals. All of these products can release organic compounds while they are being used and to some degree, when they are stored.
In research conducted by the EPA, called the Total Exposure Assessment Methodology (TEAM) studies, levels of about a dozen common organic pollutants were found to be 2 to 5 times higher inside homes than outside, regardless of whether the homes were located in rural or highly industrial areas.
Additional TEAM studies indicate that while people are using products containing organic chemicals, they can expose themselves and others to very high pollutant levels and also that elevated concentrations can persist in the air long after the activity is completed. Three out of four specific organic compounds—benzene, perchloroethylene and paradichlorobenzene—are among the most prevalent organic compounds identified by the TEAM studies.
The fourth organic compound, methylene chloride, is used widely in consumer goods. The ability of organic chemicals to cause health effects varies greatly, ranging from those that are highly toxic to those with no known health effect.
Eye and respiratory tract irritation, headaches, dizziness, visual disorders, and memory impairment are among the immediate symptoms that some people have experienced soon after exposure to some organics.
At present not much is known about what health effects occur as a result of the levels of organics found in homes. Many organic compounds are known to cause cancer in animals; some are suspected of causing, or are known to cause, cancer in human.
The following steps can reduce exposure to household chemicals:
1. Follow label instructions carefully. Products often have warnings aimed at reducing exposure to the user. For example, if a label says to use the product in a ‘well-ventilated’ area, go outdoor or in areas equipped with an exhaust fan to use the product, if possible. Otherwise, open windows to provide the maximum amount of outdoor air possible.
2. Throw away partially full containers of old or unneeded chemicals safely. Because gases can leak even from closed containers, this single step could do much to lower concentrations of organic chemicals in your home. Be sure that materials you decide to keep are stored not only in a well-ventilated area but are also safely out of reach of children. Do not simply toss these unwanted products in the garbage can.
3. Buy limited-quantities. In the future, if products such as paints, paint stripper and kerosene for space heaters or gasoline for lawn mowers are used only occasionally or seasonally, buy only as much as will be used right away.
4. Keep exposure to emissions from products containing methylene chloride to a minimum. Consumer products that contain methylene chloride include paint strippers, adhesive removers, aerosol spray paints and pesticide ‘bombs’. Methylene chloride is known to cause cancer in animals.
Also, methylene chloride is converted to carbon monoxide in the body and can cause symptoms associated with exposure to carbon monoxide. Carefully read the labels containing health hazard information and cautions on the proper use of these products. Use methylene chloride-containing products outdoors when possible; use them indoors with as much ventilation as possible.
5. Keep exposure to benzene to a minimum. Benzene is a known human carcinogen. The main indoor sources of this chemical are environmental tobacco smoke, stored fuels and paint supplies and automobile emissions in attached garages. Actions which will reduce benzene exposure include eliminating smoking within the home, providing for maximum ventilation during painting, and discarding paint supplies and special fuels that will not be used immediately.
6. Keep exposure to perchloroethylene emissions from newly dry-cleaned materials to a minimum. Perchloroethylene is the chemical most widely used in dry cleaning. In laboratory studies, it has been shown to cause cancer in animals. Recent studies indicate that people breathe low levels of this chemical both in homes where dry-cleaned goods are stored and as they wear dry-cleaned clothing.
Dry cleaners, recapture the perchloroethylene during the dry cleaning process so that they can save money by reusing it and they remove more of the chemical during the pressing and finishing processes. Some dry cleaners, however, do not remove as much perchloroethylene as possible all the time.
Taking steps to minimise your exposure to this chemical is prudent. If dry-cleaned goods have a strong chemical odour when you pick them up, do not accept them until they have been properly dried. If goods with a chemical odour are retuned to you on subsequent visits, try a different dry cleaner.
9. Pesticides:
The amount of pesticides found in homes appears to be greater than can be explained by recent pesticide use in those households; other possible sources include contaminated soil or dust that floats or is tracked in from outside, stored pesticide containers and household surfaces that collect and then release the pesticides.
In addition to the active ingredient, pesticides are also made up of ingredients which are used to carry the active agent. These carrier agents are called ‘inerts’ in pesticides because they are not toxic to the targeted pest; nevertheless, some inerts are capable of causing health problems. From example, methylene chloride, is used as an inert.
Pesticides used in and around the home include products to control insects (insecticides), termites (termiticides), rodents (rodenticides) and fungi (fungicides). They are sold as sprays, liquids, sticks, powders, crystals, balls and foggers or ‘bombs’.
Chlordane and three other related termiticides (the (‘cyclodienes’) — heptachlor, aldrin and dieldrin— deserve special attention because of their ability to remain active for long periods of time. In recent studies, air samples taken in homes soon after well-applied termiticide treatments contained residues of these chemicals.
Both the active and inert ingredients of pesticides can be organic compounds; therefore, both can add to the levels of airborne organics inside homes. However, there is little understanding at present about what concentrations are necessary to produce these effects.
Exposure to high levels of cyclodienes, commonly associated with misapplication, has produced various symptoms, including headaches, dizziness, muscle twitching, weakness, tingling sensations and nausea. In addition, the EPA is concerned that cyclodienes might cause long-term damage to the liver and the central nervous system, as well as increased risk of cancer.
The following steps can reduce exposure to pesticides in the home:
1. Read the Label and Follow the Directions:
It is illegal to use any pesticides in any manner inconsistent with the directions on its label. Unless you have had special training and are certified, never use a pesticide that is restricted to use by state-certified pest control operators. Such pesticides are simply too dangerous for application by a non-certified person. Use only the pesticides approved for use by the general public and then only in recommended amounts; increasing the amount does not offer more protection against pests and can be harmful to you and your plants or pets.
2. Use in Well-Ventilated Areas:
Open windows when applying pesticides. Mix or dilute pesticides outdoors or in a well-ventilated area and only in the amounts that will be immediately needed. If possible, take plants or pets outside when applying pesticides to them.
3. Use Alternative Non-Chemical Methods for Pest Control:
Since pesticides can be found far from the site of their original application, it is prudent to reduce the use of chemical pesticides outdoors as well as indoors. Depending on the site and pest to be controlled, one or more of the following steps can be effective: use of biological pesticides, such as Bacillus thuringiensis for the control of gypsy moths; selection of disease-resistant plants; and frequent washing of indoor plants or pets.
Termite damage can be reduced or prevented by making certain that wooden building materials do not come into direct contact with the soil and by storing firewood away from the home. By appropriately fertilising, watering and aerating lawns, the need for chemical pesticide treatments of lawns can be dramatically reduced.
4. Dispose of Unwanted Pesticides Safely:
If you have unused or partially used pesticide containers you want to get rid of, dispose of them according to the directions on the label.
5. Keep Exposure to Moth Repellents to a Minimum:
One pesticide often found in the home is para- dichlorobenzene, a commonly used active ingredient in moth repellents. This chemical is known to cause cancer in animals, but substantial scientific uncertainty exists over what may be the effects, if any, of long-term human exposure to para-dichlorobenzene. Where possible, para- dichlorobenzene and items to be protected against moths, should be placed in trunks or other containers that can be stored in areas that are separately ventilated from the home, such as attics and detached garages.
Para-dichlorobenzene is also the key active ingredient in many air fresheners (in fact, some labels for moth repellents recommend that these same products be used as air fresheners or deodourants). Proper ventilation and basic household cleanliness will go a long way toward preventing unpleasant odours, thereby reducing or eliminating the need for air refresheners.
10. Electro-Magnetic Pollution:
Pollution by electromagnetic rays (EMR) from transformers, tube lights, radios, televisions, air conditioning units etc., is highly dangerous and has deleterious effects on the human beings. Though the study of the effects of electromagnetic pollution on man is still in its primary stage it has already been shown that rats subjected to EMR have shown an increase in temperature of rectum and ultimate death. Children must be kept as far away as possible from these sources of EMR.