Freshening the Air on Indoor Air Pollution
The World Health Organization estimates that 30 percent of new and remodeled buildings may have some form of indoor air pollution (IAP), and the Environmental Protection Agency says that 33 to 50 percent of commercial buildings may have an IAP condition. These statistics indicate that companies should proactively prevent pollution problems through mitigative and diagnostic measures.
According to Robert T. Warren, assistant vice president and safety and environmental consultant for MM Protection Consultants in Toronto, some IAP conditions stem from ventilation problems caused by energy conservation programs undertaken during the 1970s. "Some of these buildings were sealed to prevent infiltration of untempered, outside air," he said. However, in these sealed buildings, ventilation is often inadequate. Mr. Warren added that synthetic materials used in the construction of some of the newer buildings can also lead to IAP problems.
IAP can also be caused by bioaerosols such as pollen; microbial agents including bacteria, viruses and fungi; chemicals such as formaldehyde (which are released by synthetic building materials, carpeting or process emissions); tobacco smoke, carbon dioxide; and from outside sources including automobiles, trucks and airplanes, said Mr. Warren. "A breakdown of the causes of IAP reveals that 50 percent are related to deficiencies in ventilation systems, which can become breeding grounds for bacteria, and that 30 percent are related to air contaminants such as solvent vapors and dust," he said. "Another 10 percent are due to outdoor sources of pollution such as motor vehicle exhausts, pollen, smoke and construction dusts, and 10 percent of cases have no discernible cause."
The term "sick building syndrome" has been used to describe the symptoms building occupants experience during an IAP episode. "To be a true IAP problem, the poor indoor air quality must be related to the occupants' symptoms," said Mr. Warren. "Also, the symptoms should end when employees leave the office and go home." Typical symptoms include respiratory problems, skin irritations, fatigue, headache, and nausea, all which are more likely to arise in the afternoon due to escalating carbon dioxide levels.
When conducting an investigation of a building's air quality, the first step should be to hold a conference. "The conference should be attended by a representative of the company or the building owner, a person knowledgeable about the operation and maintenance of the building's HVAC system and, if requested by the employees, a person who will represent their concerns," said Mr. …