An Introduction to Indoor Air Quality (IAQ) Pollutants and Sources of Indoor Air PollutionFormaldehyde/Pressed Wood Products Household Cleaning and Maintenance, Personal Care, or Hobbies Secondhand Smoke/Environmental Tobacco Smoke Stoves, Heaters, Fireplaces, and Chimneys
Contents What Causes Indoor Air Problems? Indoor Air Pollution and Health Additional Resources
Please Note: The Information provided here comes primarily from EPA's "The Inside Story: A Guide to Indoor Air Quality". The information provided here is based on current scientific and technical understanding of the issues presented and is reflective of the jurisdictional boundaries established by the statutes governing the co-authoring agencies. Following the advice given will not necessarily provide complete protection in all situations or against all health hazards that may be caused by indoor air pollution. What Causes Indoor Air Problems? Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems in homes. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home. High temperature and humidity levels can also increase concentrations of some pollutants. Pollutant Sources There are many sources of indoor air pollution in any home. These include combustion sources such as oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deteriorated, asbestos-containing insulation, wet or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; central heating and cooling systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution. The relative importance of any single source depends on how much of a given pollutant it emits and how hazardous those emissions are. In some cases, factors such as how old the source is and whether it is properly maintained are significant. For example, an improperly adjusted gas stove can emit significantly more carbon monoxide than one that is properly adjusted. Some sources, such as building materials, furnishings, and household products like air fresheners, release pollutants more or less continuously. Other sources, related to activities carried out in the home, release pollutants intermittently. These include smoking, the use of unvented or malfunctioning stoves, furnaces, or space heaters, the use of solvents in cleaning and hobby activities, the use of paint strippers in redecorating activities, and the use of cleaning products and pesticides in house-keeping. High pollutant concentrations can remain in the air for long periods after some of these activities. Amount of Ventilation If too little outdoor air enters a home, pollutants can accumulate to levels that can pose health and comfort problems. Unless they are built with special mechanical means of ventilation, homes that are designed and constructed to minimize the amount of outdoor air that can "leak" into and out of the home may have higher pollutant levels than other homes. However, because some weather conditions can drastically reduce the amount of outdoor air that enters a home, pollutants can build up even in homes that are normally considered "leaky". How Does Outdoor Air Enter a House?
Outdoor air enters and leaves a house by: infiltration, natural ventilation, and mechanical ventilation. In a process known as infiltration, outdoor air flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors. In natural ventilation, air moves through opened windows and doors. Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind. Finally, there are a number of mechanical ventilation devices, from outdoor-vented fans that intermittently remove air from a single room, such as bathrooms and kitchen, to air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house. The rate at which outdoor air replaces indoor air is described as the air exchange rate. When there is little infiltration, natural ventilation, or mechanical ventilation, the air exchange rate is low and pollutant levels can increase. Indoor Air Pollution and Health Health effects from indoor air pollutants may be experienced soon after exposure or, possibly, years later. Immediate Effects Immediate effects may show up after a single exposure or repeated exposures. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating the person's exposure to the source of the pollution, if it can be identified. Symptoms of some diseases, including asthma, hypersensitivity pneumonitis, and humidifier fever, may also show up soon after exposure to some indoor air pollutants. The likelihood of immediate reactions to indoor air pollutants depends on several factors. Age and preexisting medical conditions are two important influences. In other cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person. Some people can become sensitized to biological pollutants after repeated exposures, and it appears that some people can become sensitized to chemical pollutants as well. Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution. For this reason, it is important to pay attention to the time and place symptoms occur. If the symptoms fade or go away when a person is away from home, for example, an effort should be made to identify indoor air sources that may be possible causes. Some effects may be made worse by an inadequate supply of outdoor air or from the heating, cooling, or humidity conditions prevalent in the home. Long Term Effects Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure. These effects, which include some respiratory diseases, heart disease, and cancer, can be severely debilitating or fatal. It is prudent to try to improve the indoor air quality in your home even if symptoms are not noticeable. While pollutants commonly found in indoor air are responsible for many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific health problems. People also react very differently to exposure to indoor air pollutants. Further research is needed to better understand which health effects occur after exposure to the average pollutant concentrations found in homes and which occurs from the higher concentrations that occur for short periods of time. Additional Resources from the EPA Copyright 2007 Ronald Sauve All Rights Reserved This page was last modified on March 28, 2008 10:23 PM Bookmark this site! Indoor Air Quality in Homes and Residences Get Indoor Contaminants Before They Get You Where are you storing the 80 pounds of dust your home gains every year? Most people have heard about indoor (as in, the inside of their front door) air pollution. Concern about it generally ranks fairly lowly because homeowners don't think it's much of a problem, they feel there's little they can do about it, or both.
The first assumption might be wrong in some cases, but the second-that there's nothing that can be done is absolutely wrong.
According to the U.S. Environmental Protection Agency, most people spend 90 percent of their time indoors, where they are exposed to far greater air-pollution risks than they are when strolling outdoors. Generally, the EPA says, indoor air is four or five times more polluted than outdoor air. It has found some household air samples to be 100 times more polluted.
The irony is that increasing energy efficiency of U.S. homes has created this problem, which makes sense when you think about it. The more effective a home is at sealing off the outside environment, the more likely it is to seal in unwanted indoor pollutants.
What causes good air to go bad?
A whole host of factors play a role. The list includes (but is far from limited to dust, animal hair and dander, mold spores, bacteria; smoke; pollen, dust mites, lint, and cooking grease. And these bad elements exist to a degree in even the cleanest homes. A typical 3,000-square-foot house, for example, generates 80 pounds of dust.
Cigarette smoke, of course, is one of the most damaging sources of indoor air pollution, containing about 4,000 chemical compounds, more than 40 of which are known to cause cancer in humans, the EPA says. So, rule No. 1: Don't smoke or allow others to do so in your home.
Fireplaces pollute homes, and so do solvents used in cleaning and hobby activities, paint strippers used for redecorating activities, cleaning products, and pesticides. High-pollutant concentrations can remain in the air for long periods.
Then there's most people's favorite, pollen. Insects transport a lot of pollen, but for some species of trees, wind is actually a more common distributor.
Before you run over to the Army-Navy supply story for a bio-hazard mask, take the following steps. Some are very simple and even the most ambitious can be done with common household tools. Make sure exhaust fans and dryer exhausts vent outside Ventilate your attic and crawl spaces to prevent moisture build-upIf using cool mist or ultrasonic humidifiers, clean them according to the manufacturer's instructions and refill them with fresh water dailyThoroughly clean and dry water-damaged carpets and building materials (within 24 hours, if possible) or consider replacing them Keep the house as clean as possible. House dust mites, pollens, animal dander, and other allergy-causing agents can be reduced, although not eliminated, through regular cleaning Additional Tips Include Keep pets away from home furnishings like beds and couches that can collect their dander Wash bed linens regularly to inhibit dust mitesKeep the relative humidity at 30 percent to 50 percent, both for optimal home comfort and to control the growth of biological irritants like mildew. Bonus: it'll kill dust mites, too
Clean and disinfect the basement floor drain regularly. Do not finish a basement below ground level 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
Make sure all fireplaces, wood-burning stoves, ovens, and stovetops are in proper working order and adjustment, with adequate ventilation to the outside Properly seal paints, solvents, pesticides and chemicals of any type in your home. Keep quantities to a minimum. Whenever possible, keep such items stored in the garage On a macro level, consider upgrading your heating and air-conditioning system with a state-of-the-art air cleaning system, which can work in concert with your heating and cooling system.
While there are many types of air-cleaning systems available, what matters most about any given system is how effective a job it does keeping the air inside your home clean and safe.
And that can be evaluated scientifically and objectively, thanks to a standardized measurement created to rate relative efficiency.
The industry standard used by the Federal Trade Commission, EPA, and American National Standards Institute to compare various air-cleaning technologies is called the clean-air-delivery rate, or CADR.
The CADR is the amount of clean air a system will deliver into your home for a typical three-ton system as compared to other whole-house and appliance air cleaners. Two factors affect this rating-the efficiency of the filter material and the amount of air that passes through the device.
The higher the clean-air-delivery rate, the better the system is at filtering indoor air. Do not expect a small, tabletop air cleaner to clean the air in your entire home.
That said, today's most efficient air cleaners can remove up to 99.98 percent of airborne allergens, a rate that's 120 times more effective than a typical ionic-type appliance air cleaner.
The difference can be dramatic, especially in homes with people who suffer from seasonal or other forms of allergies.
The benefits of such a system include not only cleaner, fresher air indoors, but a much healthier environment for your family, which, after all, is the most important priority for most of us. Copyright 2007 Ronald Sauve All Rights Reserved This page was last modified on March 28, 2008 10:23 PM Bookmark this site! Air-Quality Resources
They might be pernicious, but indoor contaminants can be beaten. Here's a list of resources for your battle. The Indoor Air Quality Association
A nonprofit, multi-disciplined organization, dedicated to promoting the exchange of indoor environmental information, through education and research, for the safety and well being of the general public.
U.S. EPA Indoor Air-Quality page
Here, you'll find information on and suggestions for combating a long list of contaminants. Among the pollutants are, second-hand smoke, radon, and mold.
A Brief Guide to Mold and Your Home
This is a U.S. EPA page heavy with information, much of it of acute interest to people still recovering from the hurricanes in 2005.
University of Minnesota's Health & Safety page
UofM has put together a lengthy list of common molds, with likely toxic effects and microphotography of the offenders.
California Indoor Air-Quality Program page
Some information here, like that about radon, is targeted to California residents. But the state has done a better job than most in talking about volatile organic chemicals in homes, and that problem's universal.
U.S. Consumer Product Safety Commission
This page links to many commission publications about indoor air quality.
Medline Plus
This is a service of the U.S. National Library of Medicine and the National Institutes of Health. It has a lot of solid information, but, more important, it has a search engine for locating services related to eliminating indoor air pollution. The drawback is that its coverage of states is very spotty.
Asthma Health Outcomes Project
The findings from a study of an international asthma project, conducted by the University of Michigan School of Public Health with funding from EPA.
Greenguard Environmental Institute
An independent, non-profit agency founded in 2001 to establish a third-party certification program for environmentally friendly products with low indoor air emissions.
Copyright 2008 Ronald Sauve All Rights Reserved This page was last modified on March 28, 2008 Bookmark this site!
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