Indoor Air Cartoon Journal, November 2019, Volume 2, #86
The concentration of indoor air pollutants is determined by the outcome of the competition between the source emission rate and the sink rate of air pollutants. The higher the sink rate over source emission rate, the lower will be the indoor air pollutant concentration, while the higher the source emission rate over sink rate, the higher will be the concentration of the indoor air pollutant.
Thus, the task of built environment professionals involved in the delivery of healthy and energy-efficient buildings is to ensure a higher sink rate over source emission rate of pollutants. They also need to know that a sink that is not well maintained can later be a source that potentially contributes to a high concentration of indoor air pollutants.
Evidence in the literature suggests that the design, construction, maintenance and operation of air change rate, filtration, and air purification, indoor materials, human presence and activities, environmental parameters – relative humidity, temperature, air movement, etc., and indoor air chemical reactions, can determine whether they become a source or sink of pollutants.
In fact, these factors influencing indoor air pollutant concentration could simultaneously serve as source and sink. Their effective impact on the concentration will depend on which of the two phenomena is dominant. How can designers, contractors, facility managers, and building users help in ensuring the sink effect of these factors is much higher than their source effect? Reflect on this question if you are interested in the delivery of or living in a healthy and energy-efficient indoor environment.
Do you want to know more about this topic? Read Beko (2009), Kulmala et al. (1999), Lee et al. (2005), and Zhao et al. (2001) papers.