Managing IAQ pays dividends

IAQ Backgrounder

Indoor air quality is a function of many parameters, including outdoor air quality, the design of enclosed spaces within a building, the design of the ventilation system, the way the HVAC system is operated and maintained, and the presence of sources of biological and chemical contaminants in hazardous strengths.

The number of related complaints has increased in recent years with increased building tightness, the growing use of synthetic building materials and furnishings that give off harmful gases, and energy conservation measures that reduce the amount of outside air supply. Modern office equipment (e.g. photocopiers, laser printers, computers), cleaning products, and outdoor air pollution can also increase the level of indoor air contamination. The reactions to these contaminants have led to the phenomenon of sick building syndrome (SBS). Typical complaints include headaches, nausea, fatigue, allergy symptoms, respiratory problems, eyes, nose and throat irritation.

Analysis of air samples may fail to reveal significant concentrations of any one contaminant, so the problem is often attributed to the combined effects of many pollutants at low concentrations, complicated by other environmental factors. For example, several factors influence thermal comfort, such as over-heating, under-heating, humidity extremes, drafts, and lack of air circulation. Likewise, odours are often associated with a perception of poor air quality, whether or not they cause symptoms. Environmental stressors such as noise, vibration, over-crowding, and poor workplace design and lighting can produce symptoms that may be confused with the effects of poor air quality. Further, physical discomfort or psychosocial problems (such as job stress) can reduce tolerance for substandard air.

Some studies indicate that prolonged exposure to even low levels of contaminants, particularly among the young, elderly, and immuno-compromised individuals can lead to serious health consequences. Also, incidences are sometimes localized to certain parts of a building where poor IAQ microenvironments have developed.

Factors and Sources Affecting Indoor Air Quality and Comfort