Evaluating the Risks of Indoor Air Pollution
Concern with IAP has grown markedly in the past decade and complaints associated with indoor air quality have been lodged with increased frequency. This increase may be due to the fact that in the 1970s builders started constructing buildings with fewer openable windows that were "tighter" to increase energy efficiency. Illnesses such as Legionnaires' disease, asthma, hypersensitivity pneumonitis and humidifier fever have been directly traced to air problems in buildings. Frequently, however, a significant number of building occupants experience symptoms that do not fit the pattern of any particular illness and are difficult to trace to any specific source. These symptoms can include any one or more of the following: dry or burning mucous membranes in the nose, eyes and throat; sneezing, stuffy or runny nose; fatigue or lethargy; headache; dizziness; nausea; irritability; and forgetfulness. Aside from indoor air contaminants, poor lighting, noise, vibration, thermal discomfort and psychological stress may also cause, or contribute to, these symptoms. There is no single manner, in terms of when symptoms occur or how many people in the office experience them, in which these health problems manifest themselves.
New or recently renovated buildings are particularly susceptible to IAP. Research has shown that there are usually some occupant complaints about health concerns in newer buildings. In fact, experts from the World Health Organization believe that up to 30 percent of new or remodeled commercial buildings may have unusually high rates of health complaints from occupants, and that many of these complaints may be related to indoor air quality.
CAUSES OF IAP
There are three major causes of poor indoor air quality in office buildings. The first is the presence of indoor air pollutants. Commonly found office pollutants and their sources include second-hand tobacco smoke; asbestos from insulation and fire-retardant building supplies; formaldehyde from pressed wood products, carpeting and other office furnishings; vapors from cleaning materials, rest room air fresheners, paints, adhesives, copying machines, and photography and print chemicals; biological contaminants from dirty ventilation systems or water-damaged walls, ceilings and carpets; and pesticides from poor pest management practices.
The second cause of IAP is poorly designed, maintained or operated ventilation systems. Problems linked to the ventilation system arise when, in an effort to save energy, these systems are not used to bring in adequate amounts of outdoor air. Inadequate ventilation also occurs if the air supply and return vents within each room are blocked or placed in such a way that outside air does not actually reach the breathing zone of the building's occupants.
Furthermore, improperly located outside air intake vents can cause air contaminated with automobile and truck emissions, fumes from dumpsters or air vented from rest rooms to enter the building. Ventilation systems that are inadequately cleaned are also a source of IAP through the spread of biological contaminants that have multiplied in cooling towers, humidifiers, dehumidifiers, air conditioners or the in-side surfaces of ventilation ductwork.
The use of buildings in ways that were unanticipated when they were originally constructed is the third cause of IAP problems. For example, buildings originally designed for one purpose may end up being converted for use as office space. If not properly modified during renovations, the room partitions and ventilation systems can contribute to indoor air quality problems by restricting air recirculation or by providing an inadequate supply of outside air. Also, indoor air pollutants can be circulated from portions of the building used for specialized purposes, such as restaurants, print shops and dry cleaning stores, into offices in the same building. And carbon monoxide and other components of automobile exhaust can be drawn from underground parking garages through stairwells and elevator shafts into offices. …