IAQ: Common Problems and Cost Saving Solutions

This article was originally published by American School & Hospital Facility

In schools, indoor air contaminants can either originate within the school building or be drawn in from the outdoors. If pollutant sources are not controlled, indoor air problems can develop, even if the HVAC system is properly designed, operated, and maintained. Sources of indoor air contamination include polluted outdoor air, underground sources (e.g., radon, pesticides, and leakage from underground storage tanks), and a variety of indoor sources (e.g., equipment, furnishings, and housekeeping supplies).

Concentration levels of air pollutants can vary greatly by time and location within a school building, or possibly a single classroom. Pollutants can be emitted from point sources, such as science storerooms, or from area sources, such as newly painted surfaces. And pollutants can vary with time, such as only when floor stripping is done. Indoor air often contains a variety of contaminants at concentrations that are well below any standards or guidelines for occupational exposure, so it can be difficult to relate specific health effects to exposures to specific pollutant concentrations, especially since the exposures may be to low levels of pollutant mixtures.

The IAQ problems that generally get the most attention are usually those that involve lots of complaints from staff and students. Issues can be exacerbated by allergic reactions and health issues. These often involve outdoor contaminants that are being entrained into the building with outdoor ventilation air, such as wood smoke. One of the most common issues involves vehicle emissions. Vehicle exhaust can be problematic when the school is located in an urban setting or near heavily traveled roads, such as a highway. And the exhaust from school buses, unloading b e f o r e and after school, can be a common culprit. For hospitals, special attention is required to clean the air of contaminants that may jeopardize patient safety. More outside ventilation air is commonly used in hospitals than in typical commercial spaces. Like schools, in many urban —and even many suburban—healthcare settings, outdoor air can be more problematic than indoor air.

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