Indoor Air Pollution in Cooler Months
By Owen Whetzel
Put simply, indoor air pollution is caused in a home, when there is a lack of ventilation or to put it another way, not enough indoor air is being exhausted and outdoor air entering a space. According to the U. S. Environmental Protection Agency (EPA) "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 is a problem throughout the year, but cooler months may pose a bigger hazard in your home than warmer months, as natural ventilation, such as that through an open window and exterior door, is less likely. Indoor air pollution is a risk to all, but particularly to individuals with asthma and other respiratory diseases.
There are a number of possible sources of indoor air pollution. Examples from the EPA are "…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 EPA points out that "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 housekeeping. High pollutant concentrations can remain in the air for long periods after some of these activities."
Newer homes, built to be more energy efficient by minimizing air infiltration and air leaking out, may lower heating and air conditioning costs, but may increase the chances of polluted air through inadequate ventilation. It is assumed that older homes, which leak air out around doors, windows, through the attic and crawlspace or basement, and numerous other ways, are safer. However, having a "leaky" older home doesn't mean that the air quality is what it should be. If you have an old or new home, you should be aware of the potential for indoor air pollution and find ways to improve the air quality.
There are a number of ways to ventilate a home. If you suspect that indoor air quality is poor, consider a system that intermittently removes air from one room or the whole house. Running a kitchen or bathroom exhaust fan for more than a few minutes at a time can exhaust some of the interior air. If the problem is serious, you should consider having a system engineered and installed, that continuously removes indoor air and filters air, that is drawn in.
DUCT CLEANING TO IMPROVE INDOOR AIR QUALITY
Many people have been left to believe that heating and ventilating duct cleaning is a solution to improving indoor air quality. Here is a portion of what the American Lung Association says in their September 2000 publication, "Duct Cleaning:"
"Duct cleaning has not been shown to prevent health problems, nor is scientific evidence currently available to conclusively demonstrate that particle (e.g., dust) levels in homes increase because of dirty air ducts."
Also of interest from the publication: "People who have their ducts cleaned should verify that the service provider takes steps to protect individuals from exposure to dislodged pollutants and chemicals used during the cleaning process. This may involve using HEPA filtration when cleaning, providing respirators for workers and having occupants vacate during cleaning."
The EPA does not recommend that air ducts be cleaned routinely, but "only as needed." You may want to also read "Should You Have the Air Ducts in Your Home Cleaned?" on the EPA Web site.
MOLD PROBLEMS?
A good source of information is "A Brief Guide to Mold, Moisture, and Your Home," which is on the EPA's Web Site. The guide includes an excellent list of resources and Web site links.
If you are uncertain about the best solution to a heat, humidity, ventilation or other air problem, consider consulting with several licensed, qualified heating, ventilating and air conditioning contractors; a consultant, who specializes in indoor air quality (usually listed in the Yellow Pages under "Environmental and Ecological Consultants"); or an architect.
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For More information:
Read "The Inside Story: A Guide to Indoor Air Quality" on the EPA Web site.
Live in an apartment and are concerned about indoor air quality? You can encourage building management to follow guidance in the EPA and NIOSH's publication, "Building Air Quality: A Guide for Building Owners and Facility Managers"
See also EPA's Integrated Building Evaluation and Assessment (IBEAM) Tool