A.    Combustion

Fuel in a fireplace, a furnace heating systems, a water heater system, or a gas stove consume oxygen and produce water vapour as well as air contaminants such as nitrogen dioxide, carbon monoxide, carcinogens(benzo pyrene), etc. Unless furnaces and other combustion appliances are properly supplied with air for combustion and combustion gases are properly exhausted, then exposure to some contaminants may be hazardous.

____1.    Are combustion products immediately and effectively removed from the home by chimneys and vents?
 

____2.    Is there a supply of enough air to replace those gases that were removed?
____3.    Are you using a furnace other than a fuel fired furnace (gas and oil fumes cause you discomfort, headaches, nausea, or severe reactions)?
____4.    Do you change filters regularly?
____5.    Do you clean supply and return ducting regularly?
____6.    Does flue gas ducting leak fumes into the home?
____7.    Is your boiler system well maintained (these systems contain toxic glycol antifreeze or othe solutions, which can leak into the home or enter the drinking water system through faulty valves)?
____8.    Is CO in the home being well vented out (unvented combustion appliances such as oil or gas stoves, furnaces, water heaters, damage chimneys, automobile exhaust, cigarette smoke, candle flames, and open fireplaces, can all produce CO gases)?
____9.    Are all the nitrogen oxides ventilated out (sources are stoves, furnaces, water heaters, all burning fuel oils with a high sulphur content)?
____10.    Is the carbon dioxide ventilated out (sources are combustion, and people's respiration)?
____11.    Have all your fuel fired appliances been replaced by healthier appliances (fuel burning appliances consume air and create a negative pressurization leading to infiltration of contaminants)?
____12.    Are there leaks in the chimney (leaks and backdrafting would allow hazardous combustion gases to enter the home)?
____13.    Is the chimney regularly cleaned to prevent plugging and prevent combustion gases to enter the home?
____14.    Are there tight fitting fire doors on the chimney?
____15.    Is the amount of wood and/or coal burned in the fireplace kept to a strict minimum?
____16.    Do you burn only well-seasoned wood that has been dried for at least six months?
____17.    Do you first open the draft control for a few seconds before adding more wood to a fire?
____18.    Do you smoulder your fire by damping it?
____19.    Do you avoid burning home garbage of any type?
____20.    Do you burn wood when there is a lot of wind outside (wind disperse the smoke and reduces its environmental impact)?
____21.    Do you empty the ashes frequently to avoid clogging air-intake valves?
 
Sub-section %    =    Total number of points for the subsection     x     100%
                           Total number of questions for the sub-section               5

B.        Outgassing (evaporation from solid materials)

The emission of chemicals such as solvents, softeners, cleaners, formaldehyde, organic chemicals, synthetic fabrics, rubber, plastics, waxes, polishes, paints, dyes, treatments; or may be by-products of reactions going on within, or at the surface of the material.
 

B.1        Organochlorine compounds, VOCs, Phenols, Radon gas, Toxic metals

____1.    Is the ventilation system sufficient enough to ventilate out all the emissions from organochlorine compounds (found in pesticides, solvents, cleaning fluids, paints, waxes, plastics, wood preservatives, chlorine in water)?
____2.    Is the ventilation system sufficient enough to ventilate out volatile organic compounds (VOCs) in the home (sources are paints, cleaning solvents, waxes, polishes, camp stove fuel, gasoline, oil, natural gas, dry cleaning, plastics, propane, butane, artificial and natural scents)?
____3.    Is the ventilation system sufficient enough to ventilate phenols (sources are perfumes, mouthwashes, household cleaners, mildew cleaners, polishes, waxes, air fresheners, disinfectants, glues, phenolic plastics, cigarette smoke, and wood preservatives)?
____4.    Is the ventilation system sufficient enough to ventilate out radon gas (sources are soils, rock formation, groundwater, concrete used for foundations, clay bricks, gypsum board, water supplies from wells; radon gas is not usually found in Alberta)?
____5.    Is the ventilation system sufficient enough to ventilate out emissions from toxic metals (Lead, Zinc, Mercury, Cadmium, etc.) in the home (sources are: air entering the home from a busy street, plants or fruit grown near a busy roadway, water from highway runoff used for gardening, lead paint, lead from solder in wate pipes, mercury leaking from broken thermometer and fluorescent lamp tubes, zinc coated pipe exposed to heat, old refrigerator or freezer racks are cadmium plated)?
 

B.2        Formaldehyde

____1.    Has urea formaldehyde been removed in the spaces between the walls (the foam insulation was marketed via door to door many years ago but has been removed from most homes; fumes are toxic)?
____2.    Is there formaldehyde elsewhere in the home and is the ventilation system sufficient enough to ventilate out the fumes (sources are: the glue used to bond particle board, chip board, plywoods; many construction adhesives, carpets pads, paints, wallboards, and upholstery materials)?
 
Sub-section %    =    Total number of points for the subsection     x     100%
                           Total number of questions for the sub-section               5

B.3        Fabrics, Furnishings and Finishes

____1.    Are materials such as draperies,, upholstery, carpets, bedding, clothing, synthetic fabric, free of outgassing materials or contaminants ?
____2.    Are you handling safely materials such as cotton and wool which have been treated to prevent wrinkling or staining, to change their texture and washability (often these treatments contain formaldehyde, irritating synthetic resins, dyes, etc.)?
 
Sub-section %    =    Total number of points for the subsection     x     100%
                           Total number of questions for the sub-section               5

B.4        Household and Garden Products

____1.    Have materials such as paints, oils, automobile products, sealants, adhesives, polishes, waxes, cleaners, spot removers, pesticides, and soft plastics, been stored in the garage or in a storage area outside the home (they should not be stored in a room inside the home)?
____2.    Are paints, solvents, automobile products stored in cupboards or on basement shelves well vented to outside air?
____3.    Are fuels, flammable solvents stored outside the home (they are a fire hazard and, even small amounts of the fumes can make people ill)?
____4.    Have all porous or cracked foundation been properly repaired in the basement (the inside surface may become so cold that it will cause condensation of the moisture in warm room air and thus cause mold growth)?
____5.    Are the walls, ceilings, and floors well insulated over unheated crawl spaces (the inside surface may become so cold that it will cause condensation of the moisture in warm room air and thus cause mold growth)?
____6.    Have all mold problems been taking care of (mold shows up as damp spots peeling paint; problems arecaused by dampness around bathtubs, sinks, toilets, leaky pipes, and unheated storage spaces)?
____7.    Do you avoid using aerosol sprays?
 
Sub-section %    =    Total number of points for the subsection     x     100%
                           Total number of questions for the sub-section               5

B.5        Asbestos

It is found in insulation materials, metal ductwork of old heating systems, wallboards and plasters, heat shields of stoves and fireplaces, shingles, vinyl floor tiles, ceiling panels, sprayed materials on fireproofing areas, pipe insulation, rolled linoleum, cement/asbestos board, taping and sealing compounds, ducts and boilers, siding on buildings, acoustical ceiling tiles, window putty, fuse boxes, heat reflectors, etc.

____1.    Is the home free of asbestos?
____2.    Do you make sure never to clean asbestos waste with a vacuum cleaner (this will spread the fibres everywhere; there are regualtions about disposing of asbestos)?
____3.    Has the building been constructed after 1979 (asbestos was used as insulation before 1979)?
 
Sub-section %    =    Total number of points for the subsection     x     100%
                           Total number of questions for the sub-section               5

B.6        Polychlorinated Biphenyl (PCBs)

PCB mixtures are lightly coloured liquids that often feel thick and oily. PCBs are insoluble in water so they tend to the bottom. Overheating PCB mixtures over 40 Celsiusmay cause irretant vapours that would be emitted to the environment. PCBs are present in electrical transformers, and used as coolant. PCBs were banned from production in 1977 as it posed a potential hazard to the environment and to health. But all transformers have been upgraded to the new standards.

____1.    Is the home free of any transformers, electrical devices or hydraulic equipment labeled as containing PCBs?
____2.    Is oil leaking from any machinery or devices free of PCBs?
____3.    Is the soil or groundwater free of PCB contamination?
____4.    Are fluorescent light ballast free of PCB?
 
Sub-section %    =    Total number of points for the subsection     x     100%
                           Total number of questions for the sub-section               5

B.7        Fiberglass

Fiberglass is not currently listed as a hazardous material. However, recent studies indicate that it may constitute a human health hazard. Its presence on a property does not currently require removal or encapsulation.

____1.    Has fiberglass been removed from the property (it may have been used as an insulator)?
____2.    If fiberglass has been used on any surface, has it been completely sealed (for individual fibres exposed in this condition, it is not likely to be released into the air)?
 
Sub-section %    =    Total number of points for the subsection     x     100%
                           Total number of questions for the sub-section               5


 

Oxidation is a chemical change caused  by heat, light, air, electrical activity, and chemical agents. Sources of oxidation are gas ranges, building and furnishing materials, draperies and floor coverings, air cleaners, etc.

____1.    Are all combustion appliances well vented in the home?
____2.    Are all chemicals in building and furnishing materials safe and stable?
____3.    Are unstable materials prevented from the exposure to heat and sunlight?
____4.    Are gas ranges (they emit water vapor, CO, CO2, N2, and traces of other toxic gases) directly ventilated (do they rely on kitchen fans or open windows for exhaust) to the outside?
____5.    Is ozone safely ventilated out (ozone is created by electrical discharges on oxygen: kitchen appliances, sewing machines, power tools, electronic air cleaners, ion generators, photocopiers, etc.)?
 

In the past few years, concerns have been brought forward about the health effects of electric and magnetic fields (EMFs) from appliances, home wiring, and power lines. A substantial number of studies have been conducted on the subject, with results that we are still not sure about how these fields might affect the human body. More research is needed. We are continually exposed to different levels of EMFs. Appliances must be plugged in and operating to create a magnetic field. Exposure levels vary depending on the type of appliances a person's position in relation to the appliances. Power in wiring alternates 60 times a second and makes EMFs as well. EMF levels are higher close to their source and drop off rapidly with distance.

Electromagnetic fields are produced by electric equipment. High radio frequency levels are produced by computers, TV sets, microwave ovens, radar units and radio transmitters. The health effects of high RF levels include neurological damage, eye cataract, etc.

____1.    Is the home at least 61 meters away from high voltage lines (50,000 volts)?
____2.    Is the wiring confined to an unoccupied basement or other areas of little exposure?
____3.    Are you working in your home far enough from electric equipment?
____4.    Are bedrooms and playrooms for young children located as far as possible from any high voltage power lines near the home?
____5.    Have you chosen to increase your distance from the TV set when it is on?
____6.    Are you sitting at arm's length from your computer screen?
____7.    Do you try to use hair dryers less often (they emit high levels of EMFs)?
____8.    Are your motor-driven electric clocks, fan, telephone answering machine, in your bedroom, kept away from your bed?
____9.    Do you turn off your electric blanket (especially if you are a pregnant woman) and unplug it, before going to bed?
____10.    Do you turn off the heater of your water bed before going to bed?
 

Bacteria and fungi will reproduce very quickly under conditions such as:

*    R.H. levels about 60%            *    Household temperatures
*    Darkness             *    On nutrients such as wood, dust, fibres, soil, food, natural and synthetic resins

Bacteria will cause food poisoning and fungi can produce carcinogenic toxins.

Biological contaminants such as house dust (small particles and fibres shed from fabrics, soils, people, furniture, etc.), microbes, spores, airborne pollens (from grasses, shrubs, trees, flowers), fungi, molds, mites, animal dander, bacteria, viruses, etc. all are in the form of small particles which can be circulated by air movement.

____1.    Has the home been inspected and cleaned for bacteria and fungi colonies?
____2.    Is there proper drainage away from the building (termites thrive in the damp, humid environments that often exist in basements; the first line of defence against termites is therefore to ensure proper drainage), and are cracks in the foundation properly resealed with mortar or caulking (cracks provide access to insects), and is the site clear of dead or rotting wood which can provide food for a colony of hungry insects?
____3.    If you suspect or have identified termite damage (the most visible sign of termites is their mud tubes which are 6 to 12 mm wide, and which allow the termites to cross over foundation walls or stell), have you contacted your municipality (some have a termite control office; the treatment against termites involves chemical treatment of the ground around and below the house, and some treatment of interior surfaces of the home)?
 

If the home has been built before 1950 and has chipping, cracking or peeling paint and the plumbing was installed before 1950, then it is very likely lead can be found in your home and must be removed. Exposure to large amounts of lead can cause serious illness or death. Exposure to very low levels of lead can effect the development of a child's brain and nervous system, impair male fertility and increase the chances of complications during pregnancy.

Federal and provincial laws now limit the amount of lead in commercial products and establish limits on the amount of lead in water, soil, gasoline, paints, lead solders, and canned food.

Sources of lead exposure in and around the home can be flakes or dust from old paint containing lead, contaminated soil and water pipes. Paint chips might be swallowed by young children. In 1976, federal government regulations imposed a limit of 0.5 percent by weight. The Canadian guidelines for drinking water quality specify that the lead level in drinking water must be below 10 parts per billion.

if your home was built before 1979, the interior or exterior paint may contain small amounts of lead. Most paint manufacturers have stopped using lead altogether after the regulations were passed. If the old lead-containing paint is deteriorating you must call a pollutant specialist who will do of three things: encapsulation, replacement or removal. If your soil is contaminated, you must arrange to have a soil specialist to have it analyzed. Contaminated soil can be removed or covered depending onnthe lead level.

Your municipally treated drinking water may pick up lead from plumbing system serving homes. If there is lead in plumbing, it may also get into the drinking water. There may be lead in piping of the water delivery system to your home.

____1.    If your home has been built before 1950, have you has a lead specialist to inspect the lead content of your home?
____2.    Do you keep play areas dust-free and make sure children wash their hands regularly?
____3.    Do you remove outdoor shoes at the door or put a mat at the entrance (clean it often)?
____4.    Do you vacuum your home regularly, especially carpets which can trap dust?
____5.    Do you change work clothes and shower after working around lead on the job or work place at home (wash clothes separately from the family laundry)?
____6.    Do you damp-clean floors and other hard surfaces?
____7.    Do you practice special care with hobby materials that contain lead?
____8.    Do you keep gardens and play areas away from sources of lead?
____9.    Have you grown grass on a contaminated area to reduce the amount of dirt picked up and brought into  your home?
____10.    If you suspect that your drinking water has lead in it, do you reduce your lead intake by letting the water run for a few minutes until it runs as cold as possible (hot water picks up more lead than cold water, so it is best not to use water from the hot tap for drinking and cooking)?
____11.    Do you make sure not to serve food in ceramic pottery decorated with lead-based glazes (pottery sold in Canada is usually safe)?
____12.    Do you make sure not to store alcoholic beverages in lead crystal for long periods of time (they may contain high level of lead)?
____13.    Do you make sure ot to burn painted or treated wood with coloured inks in the fireplace or woodstove (they may contain lead or other chemicals and burning them will release lead fumes)?
 

Construction materials are very often the cause of pollution and health problems in a home.

In this sub-section building materials have been classified as A, B and/or C, depending on the grade of contamination they may produce.

The following scoring method is used:

A    =    4 or 5,            B    =    2 or 3,                C    =    0 or 1. If it is does not apply to your home it must be left out and the total number of questions is reduced by one.

A materials (4,5)

Generally stable; will not deteriorate; not expected to produce indoor contamination; safe, except for those very sensitive individuals and those suffering from environmental illness.

B materials (2,3)

Potentially hazardous contaminants; may be unacceptable to very sensitive individuals; they should be self-tested.

C materials (0,1)

Linked with serious contamination and health problems. Should be avoided.
 

Question to answer in relation to the table:

What pollutants in the following list of building materials are found in the home?

Circle the respective asterisk to indicate the pollutant material found. Indicate a number from 0 to 5 on the space before the number in the first column. Your number value is your assessment as to how important and serious is the problem. A value of zero is very serious. A value of five tells you that the material is fine (see definition above).
 

The following assessment is about major contaminants in homes. To assess contaminants the following scoring method is used:

if senses detect the presence of a contaminant listed here or if the residents of the home agree that a contaminant is observed or has been used in the home, then the score is zero;

if the contaminant is not observed in the home then the score is five.

YES    =    0,            NO    =    5.

____1.    Ammonia        Household ammonia, window cleaners, cleaners, glue, paint.
____2.    Asbestos        Street dust, old plaster, ceiling tile, wallboard, floor tile, heating ducts, insulation.
____3.    Carbon Dioxide    Poor ventilation, fuel burning stoves and heaters, faulty chimneys, respiration.
____4.    Carbon Monoxide    Auto exhaust, open flame, fuel burning stoves and heaters, faulty chimneys, natural oxidation of household chemicals.
____5.    Chlorine and Organochlorines    Bleach, scouring powder, pesticides, chlorinated water, plastics and rubber.
____6.    Dust    Pollens, soil, auto exhaust, industrial emissions, pets, construction, smoking cooking, fires, carpets, fabrics, building materials.
____7.    Formaldehyde    Incinerators, auto exhaust, industrial emissions, insulation, glue, carpet, fabric treatments, paints, waxes, polishes, insecticides, paper treatments, plastics, wood treatments, concrete and plaster additives, wallboard, toothpaste, mouthwash, germicides, cosmetics.
____8.    Fungus    Yard and garden, dampness in bathrooms and basements, walls, ceilings and floors, mildew in bedding, carpets, fabrics and clothing, refrigerators, spoiled food, humidifiers.
____9.    Gas(natural gas, propane, butane)    Heating and cooking fuel, campstoves, lanterns, lighters, hairspray.
____10.    Lead    Auto exhaust, industrial emission, water pipes, old paint.
____11.    Mercury    Industrial emission, paints, contaminated water.
____12.    Phenols    Desinfectants, cleaners, glues, mildew cleaner, plastics, wood preservatives, waxes and polishers, air fresheners.
____13.    Nitrogen Oxides    Auto exhaust, industrial emissions, fuel burning stoves and heaters, faulty chimneys, cooking.
____14.    Other Volatile Organic Compounds (VOCs)   
                Alcohols:    Shellac, inks, cleaners, desinfectants, rubber and plastics, cosmetics, medications, food flavorings, liquour.
                Refrigerants:    Gasoline, diesel. motor oils, household oils, aerosol sprays, air conditioners, refrigerators, heat pumps.
                Solvents:    Paints, varnishes, cleaners, glues, waxes, polishes, drycleaning fluid.
                Wood Resins:    Plant turpentine from softwoods (pine, fir, spruce, cedar, cypress, hemlock, cones, needles or pitch)
                Scents:    Perfumed soaps and cleaners, plants and flowers, artificial flavorings.
                Fuels and Lubricants
                Propellants
____15.    Ozone    Urban air pollution, electronic air cleaners and ionizers, electric motors, photocopiers.
____16.    Radon    Soil, rock, deep well water, concrete, stone, brick, gypsum board.
____17.    Sulphur Dioxide    Industrial emissions, fuel oil and coal burning.
 

The following assessment is about potential hazard sources in homes. To assess the presence or absence of these hazards we apply the following scoring method:

if the hazard is observed in your home then          YES    =    0,

if the hazard does not apply or is not observed then        NO    =    5.

Or you may also give any suitable value in between 0 and 5.

____1.    Formaldehyde (HCHO)    It belongs to a group of simple hydrocarbons very widely used in manufacturing today. It is probablythe most widely known indoor air contaminant, particularly because the disaster over the widespread use of urea formaldehyde foam insulation (UFFI) eg. mid. 1970's. As a result, there are a number of health problems.
            Health hazards:    Formaldehyde is a potent irritant, which affects the eyes, nose, throat and lungs, and may also cause skin reactions. Exposure has also been shown to cause headaches, depression, dizziness and loss of sleep in cases of chronic exposure such as UFFI insulated homes. Formaldehyde also aggravates coughs and colds and trigger a number of other, more serious illness such as asthma. According to a recent study one of every five persons is sensitive to exposure. It is also connected to certain cancer increasing risks.

____2.    Organochlorines    Chemical combinations of organic chemicals, hydrogen and carbon. Many pesticides are organochlorines. They are usually the most toxic compounds in this family as well as the most persistent in the environment and human and animal tissues. Many liquid solvents are organochlorines compounds. They are found in cleaning fluids, and some paints, waxes, and plastics. PVC, a potent carcinogenic which can easily enter air or water. PCB's is also in this family. They are found in electrical equipment and some plastics. Organochlorines are also formed when the chlorine in treated water combines with naturally occurring organic compounds. As a result the production of toxic gases, such as chloroform and chloramine.
            Health hazards:    Virtually all organochlorines are toxic, and some, such as pesticides, are highly toxic and carcinogenic; others such as cleaning solvents, accumulate and seriously damage such organs as the liver and kidney. Most are soluble in the body's fatty tissues, where they collect and are later released into the bloodstream with toxic result. PVC and PCB combine directly with our genetic material, causing cancer. Other organochlorines, such as the chloroform gas produced by chlorine in water, are serious respiratory irritants, and are toxic to body cells.

____3.    Volatile Organic Compounds    This very large family of chemicals includes all the organic compounds (containing hydrogen and carbon) which readily evaporate and cause air pollution. Though at room temperature most are liquids, they will readily enter air, especially when heated many are also found contaminating water, and they are used as additives to solids, such as plastics. Many volatile organics are extracted directly from petroleum oil and gas; others such as alcohols are produced sysnthetically by chemical methods. Most are used as solvents. They are usually intoxicants or asphyxiants (causing soffocation), and some are toxic to brain cells, they may also be explosive. All are potential hazards to sensitive persons. This family includes alkanes, alkenes, naphthas, benzenes, toluene, xylene, ethers, mineral spirits, alcohols (methyl and ethyl compounds); ketones, aldehydes, propane, butane, polymers, and monomers.
            Health hazards:    Most are asphyxiants. They may cause dizziness, disorientation, or death, in large doses. Some are depressants, acting on the central nervous system and causing fatigue and muscle weakness. Most are also skin and lung irritants. Some are carcinogenic or cause kidney or liver damage. Because most are soluble in fatty tissue, they are readily absorbed, and in some cases stored in our bodies.

____4.    Phenols (C6H5OH)    Phenols are organic compounds derived from coal tar or petroleum, and are used extensively in household products. The phenols include biphenyl, phenolics, and pentachlorophenol (P,C.P.). Pure phenol (known as carbolic acid) is a potent desinfectant and antiseptic. It is widely used in hospitals and homes. It is a serious incitant to many sensitive individuals. Phenol is also used in synthesis of plastic resins and wood preservatives, and is present in tobacco smoke.
             Health hazards:    Phenol and phenol compounds are highly sensitizing to skin and are suspected to be carcinogenic. Severe reactions in sensitive individuals are dangerous and can be life threatening.

____5.    Radon (RN22)    Radon is colorless, odorless gas that is a serious threat to health in some regions of the world. It is produced in certain geologic zones by the radioactive decay of naturally occurring radium. Tough radon is actually relatively harmless in itself, it is the medium by which soil radioactivity enters the home. Once inside, radon decays into other radioactive products, the most hazardous beig the polonium isotopes. These particles easily attach themselves to dust particles which are inhaled and lodged in the bronchial tubes and lungs. Once there, the isotopes release minute but very focused  doses of dangerous alpha radiation into the tissues.
            Health hazards:    Radiation released within the body will strike glues, which may then cause the kind of genetic mutations that eventually lead to cancer. Cancer risk is usually expressed in statistical terms, and radiation exposure of this type increases the risk of developing lung or throat cancer in our lifetime. Other factors, such as smoking, will further increase this risk.

____6.    Carbon Monoxide (MO)    Carbon monoxide is a very dangerous, colorless, odorless gas not normally found in significant quantities in the air around us. It is produced by incomplete combustion, such as in poorly adjusted gas flames and automobile engines. It is easily absorbed by the bloodstream and rapidly interferes with normal breathing.
            Health hazards:     Carbon monoxide combines with blood hemoglobin, reducing the body's capacity to absorb oxygen. In very small concentrations it may cause intoxication and headache; in larger doses it will cause asphyxiation and death. Exposure to dangerous levels may cause long term neurological damage. Increased levels are particularly dangerous to people with heart and lung disorders, and with circulation problems.

____7.    Nitrogen Oxides (NO, NO2)    Oxides of Nitrogen are strong smelling, highly irritating, and toxic gases. They are responsible in part for the brown haze found in urban gases. They are by-products of combustion and the action of sunlight on polluted air.
             Health hazards:    Oxides of Nitrogen are highly irritating to mucous and lung tissues, and the corrosive product produced when nitrogen (NO2) comes into contact with moist lung and bronchial membrane will cause tissue damage. With prolonged exposure lung function will be impaired. This kind of damage is seen in lung  diseases such as emphysema in smokers, and in people with high exposure in the workplace. NO2 exposure also causes depression of the white blood cells, reducing immunity to disease.

____8.    Sulphur Dioxide (SO2)    Sulphur dioxide is a colorless gas with a sharp odor not normally found in significant amounts in 'natural air.' It is formed by the oxidation of the sulphur contained in various fuels when they are burned. Sulphur dioxide from coal burning plants and other industrial processes forms a caustic acid combined with water. This is a major contributor to acid rain.
                Health hazards: The acid irritant formed when sulphur dioxide comes into contact with bronchial and lung tissues leads to increased minor respiratory illnesses, such as colds with coughs and bronchitis.

____9.    Ozone (O3)    Ozone is a colorless, unstable gas with a pungent odor usually associated with electrical equipment. Ozone decays rapidly into harmless oxygen, but it can be very irritating even in minute concentrations, particularly to people with respiratory problems.
                Health hazards:     Ozone is a respiratory irritant which causes temporary damage to mucous membranes and ling tissue. Ozone exposure also affects visual performance and judgement. It is particularly hazardous to people suffering from asthma, hay fever, emphysema, and other respiratory illnesses.

____10.    Carbon Dioxide (CO2)    Carbon dioxide is a colorless, odorless gas, normally present in air in only small quantities. Because it is heavier than other gases and does not mix easily, it tends to accumulate in enclosure areas and near the floor.
                Health hazards:    Carbon dioxide is a central nervous system depressant which slown responses and reduces alertness. It also stimulates the urge to breathe. At above normal concentrations it causes discomfort and drowsiness; at very high levels it will cause death by suffocation. The effects of exposure to elevated levels of this gas are believed to be temporary under most circumstances.

____11.    Asbestos    Asbestos is a mineral fiber mined from the earth. It is very fire resistant, workable, and inexpensive to produce. Until recently, large amounts of abestos were used in building materials and fire resistant coatings, and even in some clothing. Now asbestos has been recognized as a serious threat to the health of those exposed to it in large amounts, or over long periods of time, and its use in consumer products has been severely restricted. Asbestos is the only natural fiber that has been linked with cancer.
            Health hazards:    Asbestos fibers freed from asbestos-containing products by wear or disturbance will enter the air. Particles that are small enough will be carried by air currents and will enter the throat and lungs. Once lodged there, they will stay and cause long term irritation and tissue damage. Over long periods of time, such accumulated asbestos is likely to cause asbestosis, a serious lung desease, and can lead to lung cancer or mesothelioma, a particular form of chest cancer.