Controlling Indoor Pollutants at their Source

Use care in choosing personal supplies, hobby materials, and cleaning solutions that are non-toxic, low emitting, and low fragrance. Cracks should be sealed, because moisture and radon can enter through them. Humidity levels should be kept between 40 and 60 percent, and your home should be cleaned regularly and garbage should not be left out. If you have an attached garage, do not let a car idle in the garage.

Sometimes, the mechanical ventilation system can cause mold. The most common ways are improperly installed or improperly cleaned central humidifiers, and fiberglass lined ductwork. Because humidifiers use water to do their job, improper installation and unclean humidifiers can promote mold that will spread throughout the home through the heating system. Fiberglass lined ductwork, used often in the late 1970's and early 1980's, and deteriorate with age, holding moisture and promoting and holding mold and fungi. If the fiberglass lining in ductwork gets wet or moldy, it should be removed.

Commonly used furnace filters were never designed to protect the occupants in the home, they were designed to protect large particles from damaging the fan unit. Furnace filters do get clogged and block airflow, reducing efficiency and raising energy costs, and they should be replaced every month or two.

Extended and high efficiency (HEPA) furnace filters remove smaller particles and can help protect home occupants from potentially harmful indoor pollutants, but no furnace filter removes gases. Before installing a high-efficiency filter, make sure your furnace is strong enough to handle the increased resistance those filters provide. Some filtration systems give off ozone. Ozone is a lung irritant and should not be inhaled.

If there is mold growing in parts of your ventilation system, such as the ductwork, or if there are vermin, like rodents and insects, or your ductwork is clogged, you first need to find out why those problems exist. There could be leaks or other problems in you ductwork or ventilation system that are causing these problems. Fixing the underlying problems should be done before cleaning the ductwork. Cleaning ducts should only be done if the problems described above exist, and once the underlying problem has been repaired. If you decide to have your ductwork cleaned, check the references of the company doing the work, and make sure steps are taken to protect home occupants, including pets.

When buying a mobile home, care should be taken to investigate ventilation options, because particle board, and many other substances that release gases, such as formaldehyde, into the indoor living spaces. Mobile home sellers are required by law to give the prospective buyer a report showing ventilation options and improvement, and capacities of existing systems to bring in outdoor air.

Attic ventilation is important because it prevents moisture damage and heat buildup in the summer. If not properly vented, the attic's insulation will gather moisture, becoming ineffective once damp, and excess heat buildup in the summer will raise cooling costs and reduce occupant comfort levels. To allow air to circulate properly through an attic, at least two ventilation sources are needed. Vents near the top of the roof, and vents at the lower edge of the roof are needed to properly circulate air. If the attic has a ceiling vapor retarder installed, a minimum of one square foot of vent area should exist for every 300 square feet of ceiling area. If the attic has no ceiling vapor retarder, twice the amount of vent area is needed, or at least one square foot of vent area for every 150 square feet of ceiling area.

This document is for informational use only, and the advice of a qualified heating, ventilation, and air conditioning technician or contractor should be solicited. Be sure to check the HVAC technician's or contractor's references, and licenses before hiring.