In the past air pollution was considered an outdoor problem. Attention focused primarily on serious smog problems caused by motor vehicles and industrial sources. Yet research in recent years has found that under many circumstances the air in our homes may not meet accepted standards set to protect the general public.
Threats to indoor air quality can come from many sources. Radon, formaldehyde and asbestos are existing materials in the home that may require corrective measures to limit human exposure. Other pollutants, such as products of combustion, result from the increased use of unvented heaters and wood stoves in the home. In addition, the rapid increase in the number of new household chemicals and pesticides in the past 20 years has introduced new threats to indoor air quality.
Compounding all of these pollution sources is the effect of home weatherization which has reduced the amount of outside air entering our homes, resulting in a concentration of pollutants. As a consequence, indoor pollution levels are often greater than those outdoors and in some cases may greatly exceed accepted air quality standards.
The dose of a contaminant that a person receives is a product of the contamination concentration or level and the time of exposure. The time of exposure is the primary difference between workplace standards and standards for the home. Many times workers in industrial settings are exposed to the same contaminants at levels much greater than those accepted for indoor air quality.
Standards set to protect the industrial worker assume exposure of a healthy adult for a limited time each day (8-10 hrs/day for 40 hrs/week). In contrast, accepted standards for indoor and outdoor air quality are established to protect all individuals -- from the infant to the elderly, including those with pre-existing health problems. They also assume that some of these individuals will be exposed for 24 hours a day.
This publication offers an overview of the more common sources that affect air quality in the home and their potential health effects. However, keep in mind that the long-term health effects from exposure to a mixture of these materials, even at low levels, are not fully known. Thus, it is important to minimize exposure to potential pollutants even if no apparent health effects are presently occurring.
While many sources of air contamination are discussed in this publication, this should not be a cause for alarm. Use this information to become aware of any known potential problems and to find ways of reducing exposure.

Radon in the Home
Radon, a colorless, odorless and tasteless radioactive gas, is found in small amounts in the earth. It is a product of the radioactive decay of uranium and radium which are found in minute amounts virtually everywhere. The concentration of radon at any given location depends on local geological formations and the quantity of radioactive material.
When the radon gas is formed in the ground, it tries to escape to the open air much like an air bubble under water. The radon in the air breaks down into other substances, but at any given time there will be a small amount that has just seeped out of the ground. This ever-present amount is called the background level. The background level of radon measures about 0.1 to 0.2 picocuries/liters (pCi/liter). The unit picocurie/liter is simply a measure of radioactive emissions produced by the decay of radon, per volume of air.
When radon breaks down, it produces substances that are solids rather than gases. Due to their electrical charge, these new solid components will stick to any other solid, even dust particles. As we breathe in air containing these contaminated dust particles, the dust and radioactive elements can become lodged in our lungs. Any further radioactive decays will occur on the soft tissue of the lung where it has the greatest potential for causing damage.
Radon escaping from the ground to the open air has the least chance of harming humans. However, the concrete floor of a building or any other solid surface will block its path to the open air, causing it to become more concentrated below that surface. Unfortunately, concrete floors are never perfectly airtight. They have cracks around their perimeter or through the middle due to expansion and contraction. There will be other openings for water lines, sewer connections, or sump pumps. These small cracks or openings allow radon built up under the slab to leak into the house. The tighter the house, the longer the radon remains before it is ultimately diluted with outdoor air containing much less radon. A crawl space under a house tends to trap less radon since much more air circulates there than under a concrete slab.
There can be other sources of radon as well, such as from well water. Porous rock that can hold water (an aquifer) may also contain uranium. When the uranium breaks down to radon gas, the radon may be absorbed by the aquifer water. Radon behaves much the same as carbon dioxide in a carbonated soft drink that bubbles out after the drink is opened.
As with most harmful substances, radon's risk to health is directly proportional to the extent of exposure. It is difficult to ever get below the background level, but you can shoot for levels that are as low as reasonably acceptable. Based on health records of uranium miners, the Environmental Protection Agency (EPA) has established some rough guidelines for radon safety. The following table outlines these suggested measures:
 
 

WHEN THE RADON LEVEL IS (pCi/liter)	SUGGESTED ACTION
Less than 4	None
4 to 20	Temporary or permanent measures should be taken to bring radon levels to less than four. Evacuation of the home is not necessary, but the higher The radon level, the quicker the need to respond.
20 to 100	Temporary measures should be taken within one to three months to reduce radon levels. More permanent measures should be planned for the near future.
More than 100	In general, temporary measures should be taken within two weeks or less to bring the radon level down. Smoking is normally discouraged. Readings well over 100 indicate that temporary evacuation is suggested.

The radon test is usually considered no more accurate than about ±25%. In addition, average radon levels during summer months may be less than half of what they were in the winter, so the variation of radon levels from month to month and the accuracy of the test do not dictate any stricter guidelines than those above. If your sample produced a reading of 4.7 in the middle of winter when your house was sealed up tight, no action would be recommended since the level would probably be well below that figure for most of the rest of the year when windows and doors are sometimes opened for ventilation.
Another way to look at the health risk of radon is to compare it to other common activities. Living in a home with a radon level of 15 would be about the same as smoking a pack of cigarettes a day. A level of 60 would be about the same as being exposed to 20,000 chest X rays a year, while 200 would be comparable to more than 60 times the nonsmoker's risk of dying from lung cancer. Obviously the higher the level, the more urgent it is to take action to reduce your exposure. Since the health risk is a product of radon level and exposure time, both factors must be considered.
Recent studies by the EPA have indicated that the combination of radon and smoking could multiply the health risks rather than add them together. For instance, suppose a pack-a-day smoker with no radon exposure has a 5% chance of getting lung cancer, and a nonsmoker exposed to 15 pCi/liter of radon also has a 5% chance of lung cancer. The combined effect of smoking and radon exposure may be a 20-25% chance of cancer, not 10% as it might seem by simply adding effects. EPA estimates that 85% of all radon-related deaths may be caused by smoking and radon exposure. Figure 1 is a best guess at the relative causes of lung cancer deaths. While smoking is far and away the major single cause, the combination of smoking and radon exposure may account for more than 15% of cancer deaths from all causes.
When the radon gas breaks down and produces small solid charged particles (called radon daughters), these particles cling to dust or any other nearby solid material. Smoking creates millions of these small smoke particles for the radon daughters to cling to. The smoke particles are very small, so they can reach into the deepest parts of the lung. A smoker, when inhaling through the cigarette, takes a much deeper breath than normal and so takes these smoke particles laden with radon daughters deeper into the lungs with less chance of their being exhaled. Based on this theory, even nonsmokers who spend a lot of time in a smoke-filled room are at greater risk due to the abundance of small smoke particles available for the radon daughters to cling to.
The most common places for radon to enter a home are through cracks in basement walls or slab floors, openings around piping or drain entry points, and open sump pits. In some cases the source may be very obvious, while in others the walls and floor may appear tight. Caulking cracks in basement walls and floors and around drains and sealing up open sumps should help reduce concentrations of radon gas.
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Another simple means of reducing radon levels is to ventilate your home more. While this may have limited possibilities in the middle of winter and in the heat of August, Kentucky has five to six months a year during which you can comfortably open windows (it doesn't take many) and greatly reduce radon levels as well as those of other pollutants. An alternative procedure for more severe problems is to mechanically vent the space below the floor (called subslab suction) or the cores of concrete block walls.
Before you do anything to prevent radon from entering your home, you should first have your home checked for high radon levels.
There are two main types of radon detectors. The cheapest and simplest is the charcoal canister. It should be placed in some central location in the home for three to seven days and then mailed in a sealed packet to a certified testing laboratory for analysis. The charcoal canister can be obtained for as little as $12 (including lab analysis).
The alternative method is an alpha track detector. This device must be in place for at least two to four weeks (preferably several months), but it gives a more accurate long-term average reading. The alpha track detector costs $20 to $50.
Before purchasing a test unit, be sure that the lab analysis will be performed in an EPA approved lab. This information will usually be prominently displayed on the test unit box or packaging material. For best results, conduct tests during periods when the house has been closed for several days and will remain closed for the test period.
Preliminary tests in the spring of 1987 in Kentucky by the Radiation Control Branch of the Department of Health Services through funding from EPA found that, overall, Kentucky does not have a severe radon problem. Out of 900 samples, only about 1% were in the 20 to 100 range, mostly on the lower end of the scale. About 16% were in the 4 to 20 range.

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Far eastern and far western Kentucky appear to have few occurrences of high radon levels. The regions with the highest probabilities of having above-average radon levels are in the counties around Mammoth Cave, in the triangle roughly bounded by Louisville, Richmond and Cincinnati, and in the Somerset area. If you live in one of these areas, you can get more information from your local health department about the test results.
If you want to test your own home, you can send a check for $12 made out to the University of Pittsburgh to: Radon Project, University of Pittsburgh, P.O. Box 90069, Pittsburgh, PA 15224. You will receive a charcoal canister in the mail with instructions and a return mailing packet. You will get a short lab report giving the radon level in your home and what steps you need to take based on that reading.
If your charcoal canister test gives a reading well above 4, you should conduct a long-term test with an alpha track detector. This test would give you a better idea of the average radon level your family is exposed to on an annual basis. If this long-term reading is well above 4, you should take steps to lower the radon level, either by sealing your house yourself or hiring a certified radon mitigator for more extensive work.
As with any contracted work, get more than one estimate for radon mitigation (reduction) work. Include in the contract a guarantee of radon reduction to be certified by an independent radon measuring firm. If the contractor will not guarantee meeting the agreed radon level for an agreed cost, look elsewhere. Your local health department or Extension office are good places to check with before contracting for any such services.

Asbestos
Asbestos is a mineral fiber that has been used in an estimated 3,000 home products through the years. Asbestos is a very durable and heat resistant material that also provides insulation for heat and sound. Because of these insulating properties, asbestos was commonly added to construction products including pipe insulation, roofing, flooring materials, insulation in heat-producing appliances and in patching compounds and textured paints. In recent years, asbestos use has declined because of the health effects, and EPA has proposed a ban on some asbestos-containing products and a phase-out of all others by the year 2000.
Asbestos has been shown to cause cancer of the lung and stomach. If the small microscopic fibers of asbestos are released into the air, they can be inhaled and become lodged in the lining of the lungs. With repeated exposure scar tissue can develop and lead to asbestosis, a disease of asbestos workers. After many years cancer or mesothelioma can also develop from asbestos in the lungs.
According to experts, there is no completely safe level of exposure to asbestos. Exposure by youngsters is a special concern because they would carry the material in their lungs for a lifetime. Smokers exposed to asbestos also have a greater risk of lung cancer-greater than the risk of cancer produced by either smoking or asbestos exposure alone.
While asbestos is present in a variety of materials in the home, it is normally not a major source of indoor air quality problems. However, if the materials start to deteriorate or if remodeling activities expose or disturb the material through sawing, sanding, etc., then it can pose a serious hazard to indoor air quality. Once the fibers have been released, clean-up or removal of the material is costly and time consuming. If asbestos materials do require removal, strict procedures should always be followed to avoid contaminating the indoor home environment.
For asbestos to be a health risk, fibers must be released from the material and inhaled. Most asbestos products do not pose a health threat while the fibers are incorporated in the product. The release of hazardous fibers normally occurs in two instances:
•when attempts are made to saw, sand, scrape or break the material, or
•when the existing structure of the material starts to deteriorate by crumbling, cracking or flaking.
Once released, the asbestos fibers may remain in the air for up to 80 hours. Dusting, sweeping or vacuuming will cause the fibers to become airborne again. (The filter of an ordinary vacuum sweeper is not fine enough to trap all the tiny fibers.)
If asbestos is found in the home, it is best not to disturb the material. If the material is in good condition and is not disturbed, it should not pose a health threat. However, if the asbestos shows signs of starting to deteriorate, take action before the fibers are released. Enclose small areas with an airtight barrier, or apply chemical sprays to coat and seal the material. These are only temporary solutions, however. Removal is often the best but most expensive solution.
Recent studies indicate that much of the fear about asbestos in buildings may be overblown. Of the three types of asbestos -- chrysotile (95% of all asbestos produced), amosite (3%)and crocidolite (1%) -- chrysotile fibers seem to be much less dangerous than the smaller amosite and crocidolite fibers. In addition, asbestos measurements in most buildings containing it are normally far below dangerous levels and so do not warrant disruption for the sake of removing concealed asbestos.
Many experts are now suggesting that regulations requiring removal of asbestos from schools be canceled in cases where the measured asbestos level in the air is very low. This is a rapidly evolving area that is likely to see major changes in both legislative and legal avenues in the 1990s.
Removal of exposed or damaged asbestos requires special precautions to prevent release of the fibers into the home. If possible, hire a contractor who is familiar with the guidelines for asbestos removal. Keep in mind that most home repair or renovation contractors are generally not experienced in removal procedures. The guidelines for safe removal include:
1.Seal off the removal area from the rest of the house with plastic sheeting and duct tape. Avoid tracking dust and debris into other parts of the home.
2.Use an approved respirator along with protective gloves, hats and coveralls during removal. Wear disposable work garments, if possible, and shower after removing the clothing.
3.Use a water spray with wetting agent (detergent)to thoroughly wet the material. This reduces the release of fibers into the air.
4.Seal all material in heavy plastic bags and approved containers for disposal in an approved sanitary landfill. Check with your local health department.
5.Thoroughly clean the confined area with a wet mop to remove all material. Repeat the procedure after 24 hours to ensure that all asbestos dust has been removed. Never dust, sweep or vacuum the material. (Contractors may use specially designed vacuums for picking up the material.)
If you suspect that a material is asbestos, first check with a person who is familiar with asbestos products, such as a plumber, building contractor or heating contractor or, if possible, the person who installed the material. To confirm the presence of asbestos, a sample can be taken and sent to an approved laboratory at a cost of $30-50. Your local health department should have a current. list of approved laboratories.
The following is a list of asbestos products commonly found in the home, along with appropriate precautions for each. Unless otherwise stated, it is best to leave the material alone if it is in good condition. If the material is deteriorating, it should be removed following the procedures described above.

Vinyl Floor Tiles & Vinyl Sheet Flooring
Asbestos was used in floor tiles and in the backing of sheet flooring. Fibers can be released from sanding or cutting of tile or dry sanding or scraping of backing materials during removal of vinyl flooring. A safe alternative is to place new flooring directly over the old tiles or sheet.

Patching Compounds & Textured Paints
Before 1977 patching compounds and textured paints often contained asbestos. Avoid cutting, sanding or scraping these surfaces.

Ceiling
Some large buildings, schools and a few homes built or remodeled between 1945 and 1978 had asbestos material either sprayed or troweled on ceilings and walls. If the material is damaged, consider having it removed. If possible, contact the builder or contractor to determine if the material contained asbestos. (This is a common source of asbestos problems in schools.)

Stoves & Furnaces
Asbestos cement board, millboard and paper were frequently used for fire protection in homes with wood-burning stoves. Rubbing or wear of the paper or millboard can result in the release of fibers. The asbestos cement board will probably not release fibers unless scraped. Furnaces often used asbestos insulation and furnace cement. Updating the heating system can result in removal or damage to this old insulation. Some door gaskets on wood stoves may also contain asbestos that can release fibers if they become worn.

Wall & Pipe Insulation
Hot water and steam pipes may be covered with asbestos-containing insulation material. Pipes and furnace ducts may also be wrapped with an asbestos "blanket" or paper tape. These materials were manufactured from 1920 to 1972. If damage occurs to this type of material, the current recommendation is to leave the material in place and repair with a protective covering, such as duct tape or other commercial product. Asbestos wall or ceiling insulation may have been used in homes constructed between 1930 and 1950.

Appliances
Some appliances such as toasters, popcorn poppers, stoves, etc. contain parts or components with asbestos. These have not caused problems with the exception of hair dryers which were recalled in 1979.

Roofing, Shingles & Siding
Roofing shingles, siding shingles and sheets were manufactured using asbestos and portland cement binding material. If these are on the outside of the home, they provide little risk to human health.

Formaldehyde
General
It seems that today we are finding more and more items that pose some danger to our health. One of these receiving recent publicity is formaldehyde, a resin used in products that account for about eight percent of the U.S. gross national product. Because of the publicity, industry is taking steps to reduce the levels of exposure. Awareness of formaldehyde problems probably reached its peak when people began to insulate and more tightly seal their homes during the energy crisis.
Formaldehyde, a pungent, colorless gas, is produced by the binders and glues used in many wood products, such as particle board, plywood and paneling. Its odor can be detected at levels less than 1 part per billion. Building materials using formaldehyde can emit the gas for years, although there is a gradual decrease. It has been found that increasing the humidity in the home increases the gas emission rate.
Sources
Some sources of formaldehyde are urea formaldehyde foam insulation, particleboard, interior grade plywood, hardwood paneling, cabinets, furniture, some cleaning agents and solvents, along with other products. Formaldehyde is also produced in small amounts as a by-product of gas combustion in gas cooking and heating equipment, especially if poorly adjusted.
Installation of urea formaldehyde foam insulation was identified as a major source of formaldehyde complaints. This led the Consumer Product Safety Commission to ban its use in the '70s, but this ruling was later overturned in the courts. Although improper installation was usually the cause of the problem, all the negative publicity resulted in the elimination of these foams for use as home insulation.
The Consumer Product Safety Commission, when petitioned to regulate formaldehyde emission rates in structural products used in homes, reported there was no great risk when conventional homes were built using conventional construction techniques. In Kentucky the largest source of formaldehyde complaints has been associated with mobile homes which use more particle board and plywood paneling in construction. Manufacturers have now set voluntary standards to reduce the amount of formaldehyde used in plywood and particle board products.

Health Effects
People vary greatly in their susceptibility to formaldehyde. People with respiratory problems or allergies, infants and the elderly usually respond more severely at lower levels. Fewer than 20% of adults may react at levels less than 0.25 parts per million (ppm). It can be generally said that healthy adults may not show any reactions at levels of 0.1 ppm or below. This is the level that the Consumer Product Safety Commission believes is safe.
Formaldehyde is primarily considered an irritant. Extensive laboratory studies with rats indicate it could be a possible human carcinogen at very high levels. Evaluations of industrial workers who have been exposed to high levels of formaldehyde have yielded no measurable cancer risk. It appears that since it is such a strong irritant, people can't tolerate being exposed to levels that would pose a possible cancer risk.

Symptoms
Identifying formaldehyde exposure effects is not simple because the same symptoms can occur for many other reasons. However, one should be suspicious if any of the following persist in a home known to have items with formaldehyde: eye, nose and throat irritations, coughing, shortness of breath; skin irritation, nausea, headaches, dizziness; sleeping difficulty, chest or abdominal pain. A medical doctor should check anyone with any of the above symptoms. Also, inform the doctor about any building materials, furniture or other items in the home that might contain formaldehyde. When a person with the above problems leaves the home for a few days and the problem disappears, formaldehyde should be a strong suspect.
Complaints are most common in the spring and fall when the house is closed up and indoor humidity levels are higher than in the winter.

Testing
There is no statewide testing facility, and one must rely on private laboratories. When tests are requested, be aware that results vary with the location at which measurements are taken, the home air humidity, the time of day and air temperature. For example, more emissions occur at higher humidity and higher temperature.

Emission Removal or Reduction
The best solution is to remove the sources of formaldehyde emissions from the home. However, this is often expensive and/or impractical, such as removing underlayment particleboard or foam wall insulation. Emissions can be reduced by using sealants over the source. For walls a mylar or vinyl wallpaper or varnish may help. For floors any sealant also helps. Adequate fresh air circulated from fans, open windows, heat exchangers, etc. helps to remove the gases, but this is not always practical. When buying paneling or particleboard for indoor use, look for those that meet industry standards.
Since high humidity contributes to higher emissions, the family needs to control humidity levels in the home. In the case of mobile homes, long-time formaldehyde levels have been reduced by 60-75% with ammonia fumigation. However, this must be done by an experienced person, and the place must be thoroughly vacuumed afterward because the treatment may produce hexamethylene tetramine which settles out as a fine white dust.

Products of Combustion
Combustion products from gas stoves, unvented gas and kerosene heaters and gas-fired furnaces and water heaters are all sources of indoor air pollution. The most common are the natural products of combustion, water vapor and carbon dioxide, which are not toxic. Others, such as carbon monoxide, are a well-recognized hazard. Other products of combustion produced in smaller quantities are nitric oxide, nitrogen dioxide, sulfur dioxide, formaldehyde and respirable particles (see definition below)which are also well recognized for their health effects.
Studies show that wood- and coal-burning stoves, fireplaces and furnaces are also sources of hydrocarbons and polycylic organic matter. Combustion products contained in tobacco smoke are another source of indoor air contamination.
The following is a list of the most common products of combustion and their health effects:

Carbon monoxide
Carbon monoxide gas is a very toxic byproduct resulting from incomplete combustion. It accumulates in the blood by replacing the oxygen and may cause headaches, dizziness, pain and tightening of the chest, blurred vision, unconsciousness and death. The groups at highest risk from elevated levels are the unborn, newborns and those with heart and lung diseases.

Carbon dioxide
Carbon dioxide is a product of combustion that is not toxic but can cause headaches, dizziness, shortness of breath and drowsiness when in high concentrations.

Nitrogen dioxide
Nitrogen dioxide causes irritation of the throat and eyes. High levels can lead to impaired breathing. The long-term health effects are not well known but could cause concern, especially for children.

Sulfur dioxide
Sulfur dioxide is very irritating to eyes and throat and may constrict upper airways. People with allergies are quite sensitive, and higher concentrations may lead to asthma attacks.

Formaldehyde
Formaldehyde causes headaches and dizziness. It is a suspected human carcinogen.

Respirable suspended particles
Respirable suspended particles are very fine carbon particles which, if inhaled, can be carried deep into the lungs (larger particles are trapped before they reach the inner lungs). They can cause respiratory problems, bronchitis and allergic reactions. Hazardous or toxic materials, such as sulfur dioxide or radon daughters, may become attached to these particles and be carried deep into the lungs.
The most common sources of these products of combustion in the home are discussed below.

Gas Cooking Stoves
Increased indoor levels of carbon monoxide, nitrogen dioxide and nitric oxide are all commonly associated with the use of gas stoves. Improper adjustment of the gas flames can also increase the production of carbon monoxide by 30 times. To minimize buildup of these pollutants, keep the flame properly adjusted and use a hood and exhaust fan with a capacity of 100 cubic feet per minute while the stove is operating.

Unvented Kerosene & Gas Space Heaters
Unvented kerosene heaters have received much attention because of their potential for indoor air pollution. Early models used in confined areas produced high levels of carbon monoxide, carbon dioxide, nitrogen dioxide and sulfur dioxide that exceeded the generally accepted indoor and outdoor air quality standards.
The levels of carbon monoxide and nitrogen dioxide emitted by the newer heaters with multi-stage combustion units have been greatly reduced, but the heaters are still a major source of air contaminants. High levels of sulfur dioxide have also been a problem, especially when inferior grades of kerosene with high sulfur content have been used.
To minimize air contaminants with kerosene heaters:
1.Use the heater in a well-ventilated area. In confined areas crack open a window or door as suggested by the manufacturer.
2.Limit use of heaters to shorter periods of time. Use the heater as a source of supplemental heat and not as .a primary heat source.
3.Follow proper maintenance and operating procedures to ensure maximum efficiency and lessen air pollution.
4.Select new multi-stage heaters which emit fewer pollutants.
5.Use only fresh, high-quality 1-K+ fuel for clean burning.
The levels of emissions from unvented natural gas space heaters depend on their size and design and the proper flame adjustment. In some cases the emission levels of carbon monoxide and formaldehyde were less than those for a gas cooking stove.
To minimize effects on indoor air quality from unvented gas heaters:
•keep the units properly adjusted
•use them in well-ventilated areas and
•limit their use to short periods as a supplemental heater rather than a primary heat source.

Wood-Burning Stoves, Furnaces & Fireplaces
While burning wood is a significant source of both indoor and outdoor air pollution, the actual emission level varies greatly, depending on the design and installation of the stove or furnace. Of most concern from wood burning are carbon monoxide, nitrogen oxides, hydrocarbons and respirable particles, including some polycyclic organic compounds which are carcinogenic, such as benzo-a-pyrene. To reduce indoor emission of fireplaces, use metal or glass doors to cover the opening. Select quality airtight woodburning stoves and furnaces and follow the manufacturer's recommended installation procedures. Be sure chimneys provide good draft, and follow operating procedures that reduce room emissions when tending the fire.

Tobacco Smoke
Smoking produces a number of air contaminants. The two most important are respirable suspended particles and carbon monoxide. Others are benzo-a-pyrene, nicotine, nitrosamines, acrolein and other aldehydes. Studies of smokers' homes showed that the average concentrations of respirable particles in the air were much higher than the outdoor level, while levels in homes of nonsmokers were comparable to those outdoors. Likewise, carbon monoxide levels measured in rooms where cigarettes were being smoked were above the EPA outdoor standard for eight hours, and in some the levels were above the accepted standard for an eight-hour-day work environment. Increasing ventilation rates and restricting indoor smoking will help reduce the indoor air pollution from tobacco smoke. However, since particulate material can cling to fabric and upholstery, ventilation alone may not reduce particulate levels as it does for other contaminants.

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Gas Furnaces & Water Heaters
Properly vented gas furnaces and water heaters are normally not a source of indoor air pollution. However, an obstruction in the vent or a crack in the furnace heat exchanger can allow vented gases to leak into the home with the potential for fatal levels of carbon monoxide. In addition, when a gas water heater or natural draft furnace starts up from a cold condition, there may be spillage of combustion gases for some time before they are drafted up the chimney.
In tightly weatherized houses, the use of bathroom and kitchen vent fans or the updraft of a fireplace may depressurize the house, causing vent gas to spill or backdraft into the home. This potential can be reduced by testing for backdrafting with the flame of a lighter and providing fresh air supplies for the furnace and/or fireplace. Some new high-efficiency heaters now have sealed combustion units which prevent backdrafting.

Organic Materials ( Household Products)
Many of the chemicals in cleaning products, polishes, glues, paint, solvents, sprays and pesticide products are toxic, and some may be carcinogenic. However, the health effects from exposure to a combination of these materials in low concentrations over long periods of time are not known.
Many of these products may have warnings on the label to use only in well-ventilated spaces. Always follow all of the manufacturer's directions for safe use of these materials. When possible avoid using chemicals and sprays inside the home. If they must be used indoors, open the windows and doors during and after their use to allow the chemicals to disperse. Any lingering odors signal the presence of the chemical pollutant. However, a lack of odor doesn't always mean that the pollutant is gone.

Summary
Indoor air quality should be of concern to everyone because of the potential health effects. Although everyone will not be immediately affected by poor quality indoor air, the long-term health effects are not fully known. Common sense would dictate that efforts should be made to reduce exposure to all pollutants.
If you suspect indoor air quality problems in your home, watch for the following signs: 1) A musty smell, stuffiness, or noticeable lingering odors, or 2) frequent headaches, respiratory irritation, watery eyes, nausea or fatigue among occupants.
A "yes" answer to the following questions may indicate a link between air quality and your current health problems:
1.Are symptoms reported by more than one family member?
2.Are the irritating symptoms most severe in family members who spend most of their time at home?
3.Are the symptoms severe in infants or very young children?
4.Do the symptoms become less severe when away from the home for longer periods?
5.Do the symptoms diminish when continuous ventilation is provided?
6.Are there seasonal patterns to the symptoms?
7.Are the symptoms related to moving into a new home, remodeling, new furnishing, energy conservation measures or the use of certain products?

For additional information on indoor air quality, check with your county Extension office or local health department.