Why should we care about indoor air quality (IAQ)? Because it is estimated that most people spend as much as 90% of their day indoors. According to the U.S. Environmental Protection Agency (EPA), the air within homes, schools and office buildings may be even more polluted than the outdoor air. Inadequate ventilation, humidity levels and indoor pollutants are all contributors to indoor air quality problems.

Mold
Mold spores are everywhere, and they can grow on virtually any surface when moisture is present. Molds reproduce by means of tiny spores that are invisible to the naked eye. When mold spores land on wet surfaces, they may begin to grow indoors.

Sources of moisture within buildings can include wet building materials, leaks in the building envelope or plumbing system, and HVAC condensation or flooding. Many of these problems, however, can occur during construction, when materials are installed improperly or without regard to moisture considerations. All building materials, both organic and inorganic in composition, can become breeding grounds for mold.

Secondhand Smoke
While secondhand smoke affects everyone, children are especially vulnerable. Secondhand smoke includes smoke given off by the burning end of a cigarette, pipe or cigar and the smoke exhaled from the lungs of smokers. It is implicated in a wide range of adverse health effects, including asthma, cancer, and respiratory infections.

As of 2006, 14 states, as well as the District of Columbia and Puerto Rico, have passed smoke-free air laws, according to the American Lung Association. As of 2005, nine of those states prohibit smoking in almost all workplaces, including restaurants and bars.

Asthma
According to the American Lung Association, asthma afflicts about 20 million Americans. The EPA estimates that 6.3 million of those sufferers are children. In 2000, asthma accounted for more than 14 million missed school days.

According to the EPA, twenty percent of the U.S. population, or nearly 55 million people, spend their days in elementary and secondary schools. In the mid-1990s, studies showed that 20% of U.S. schools reported unsatisfactory indoor air quality. Because children spend hours each day at school and are more susceptible to pollutants, they are particularly at risk.

Sick Building Syndrome (SBS)
The World Health Organization (WHO) estimates that up to 30 percent of new and remodeled buildings worldwide contain factors that may contribute to SBS. In those buildings, approximately a third of occupants may experience malaise related to poor air quality. Symptoms may include dry cough, fatigue, lack of focus, eye, nose or throat irritation, nausea and dizziness, and sensitivity to odors.

The EPA identifies four contributing factors to SBS that may act together or in conjunction with inadequate temperature, humidity or lighting:

• Inadequate ventilation Heating, ventilating, and air conditioning (HVAC) systems that don't effectively distribute air to people in the building may be a factor in SBS. In an effort to achieve acceptable IAQ while minimizing energy consumption, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) provides standards on the minimum controlled ventilation rates in cubic feet per minute (cfm) per person (see ASHRAE Standard 62-2004).



• Biological contaminants Pollen, viruses, bacteria and molds can breed in stagnant water that accumulates in ducts, humidifiers and drain pans, or on moist ceilings tiles, carpeting or insulation. Physical symptoms of biological contamination include cough, chest tightness, fever, and muscle aches.



• Indoor chemical contaminants Most indoor air pollution comes from sources within the building, including adhesives, carpeting, office furniture, manufactured wood products, copy machines, and cleaning products. These often emit volatile organic compounds (VOCs), including formaldehyde. Some VOCs (for example, formaldehyde) are known carcinogens.



• Outdoor chemical contaminants Pollution from motor vehicles, construction, adjacent building exhaust, and plumbing vents can enter a building.