Indoor Air Cartoon Journal, December 2018, Volume 1, #38

The best way to reduce the human risk of developing adverse health implications from indoor air pollutants is to eliminate or reduce the hazard – air pollutants concentration. So, how to reduce the concentration of a particular indoor air pollutant? There are three basic strategies for achieving this purpose. They are source elimination or reduction, ventilation, and air cleaning strategies. How do they reduce the concentration? To appreciate the answer to this question, an understanding of concentration is essential. Concentration is the amount – mass, area, volume or number – of a particular pollutant present in a volume of air of indoor space. That means a reduction to the amount of the pollutant present in indoor air or an increase in the volume of clean air in indoor space will reduce the concentration.

Source elimination means there is no source that could emit the unwanted pollutant into the air. Source reduction means there is a lesser amount of sources emitting the pollutant into the air. It also means reducing its source emission rate. If source elimination or reduction strategy is adopted, the concentration of the pollutant will be negligible or lesser.

Ventilation uses outdoor air, which is expected to be cleaner, to reduce the concentration of indoor air pollutants through the provision of a larger volume of “cleaner” air. This phenomenon is known as dilution. Ventilation strategy also uses the volume of the “cleaner” air to displace pollutants from indoor space. The benefit of ventilation strategy will be compromised if outdoor air is not clean. Air cleaning strategy, through filtration or other cleaning measures, “hunts” and removes pollutants from the air. Air cleaning strategy helps to purify recirculated or outdoor air transported into indoor air.

Do you want to know more about this topic? Read Fadeyi et al. (2009) and Walker and Sherman (2013) papers.