Construction Industry Trends
October 2005
The Growing Interest in Indoor Air Quality
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When members of the construction industry talk about the environment, more often than not, they’re concerned with what’s going on inside their buildings rather than outside them.
Indoor air quality, or IAQ, has become a hot topic in construction, and for good reason. With people spending approximately 90 percent of their time indoors, they are much more likely to be impacted by pollutants in their homes, offices and schools than outside them. While many think of pollutants occurring outside, they are a much bigger threat inside—according to the U.S. General Accounting Office, the concentration of pollutants in indoor air can be two to five times higher than what is found in outside air. Exposure to indoor air pollutants has been shown to lead to a number of health problems, including sick-building syndrome, a collection of symptoms directly linked to IAQ. Because of this, the U.S. Environmental Protection Agency (EPA) has identified poor IAQ as the fourth largest environmental threat in the United States.
Today’s interest in IAQ stems from the increasing emphasis on energy efficiency. In the early 1970s, under pressure from rapidly increasing energy prices, builders focused on developing an air-tight building envelope that would better conserve energy. By recirculating air rather than bringing fresh air in from the outside, buildings did become more efficient, but created another problem—poor air quality.
Without proper ventilation, indoor air concentrates pollutants, which come from a number of sources, including:
- Biological contaminants. People, animals, plants, insects, and water can all result in the growth and release of microorganisms such as mold, mildew, bacteria, funguses, viruses, pollen, and dander.
- Combustion sources. Gases such as carbon monoxide and nitrogen dioxide can be released by improperly installed or maintained combustion sources such as stoves, heaters, and fireplaces.
- Building materials, furnishings, and household products. Thousands of products as diverse as paints, pressed-wood products, household cleaners, and office supplies emit gases known as volatile organic chemicals, or VOCs, some of which are suspected of causing cancer in humans. Also, while limited in use in recent years, asbestos, another potential pollutant source, is often found in older homes and buildings.
- Outdoor pollutants. Outdoor pollutants such as smog, pesticides, and radon become much more concentrated in indoor environments that lack proper ventilation. Radon, a naturally occurring gas, is suspected by the World Health Organization of causing up to 15 percent of lung cancers worldwide.
Although ventilation is key to reducing indoor air pollutants, the push is on in the industry to find ways to also reduce the sources of pollutants during the building process. Those involved in the green building movement are not only focusing on increasing the use of recyclable and renewable materials and decreasing energy consumption, but also looking at ways to reduce the use of materials that contribute to indoor air pollution.
To help in this effort, the EPA is offering a free tool for builders and those responsible for IAQ for commercial buildings. The Indoor Air Quality Building Education and Assessment guidance (I-BEAM) provides users with text materials and visual education guides as well as a module designed to help with the calculation of costs associated with IAQ-related activities. I-BEAM is one of only a number of initiatives within the industry to improve understanding of IAQ and its impact on building occupants.
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