Even after a building investigation, however, the specific causes of the complaints may remain unknown. Several of these options may be exercised at one time. Increasing ventilation rates and air distribution often can be a cost effective means of reducing indoor pollutant levels. When there are strong pollutant sources, local exhaust ventilation may be appropriate to exhaust contaminated air directly from the building. Local exhaust ventilation is particularly recommended to remove pollutants that accumulate in specific areas such as rest rooms, copy rooms, and printing facilities.
Air cleaning can be a useful adjunct to source control and ventilation but has certain limitations.
Mechanical filters do not remove gaseous pollutants. Some specific gaseous pollutants may be removed by adsorbent beds, but these devices can be expensive and require frequent replacement of the adsorbent material. Air cleaners can be useful, but have limited application. Education and communication are important elements in both remedial and preventive indoor air quality management programs.