Indoor Air Cartoon Journal, December 2018, Volume 1, #39
There are several studies in the literature documenting indoor chemistry phenomenon, its impact on human health, and possible ways of controlling the impact. Products of indoor air chemistry could even be more harmful than the reactants themselves. In as much as the studies are very important, translation to industry practice needs improvement. A typical facility manager or designer would not benefit from most of the indoor chemistry research articles as the technicalities could be very difficult for them to grasp. This week’s indoor air cartoon issue provides an analogy that could make anyone, irrespective of their profession or expertise, to understand and appreciate the main idea of indoor chemistry and its control.
The main idea of indoor chemistry is the reaction between pollutants that have high enthalpy (energy) and are very attracted towards one another due to their unstable bonds. The reaction leads to new pollutant(s) that may not exist in the indoor environment initially or present at low or high concentration. The concern is, the product from the chemistry may even be more harmful than the reactants themselves. So, it is no brainer that keeping the reactive pollutants apart or avoiding their co-occurrence as much as possible will reduce the concentration of the harmful chemistry products. This strategy will only be effective if the reactive pollutants in question are known. However, in reality, there are several unknown reactive pollutants and chemistry products. Even if these pollutants are known to the experts in the area, the majority of designers or facility managers with no chemistry expertise will not know these chemicals.
Adoption of effective ventilation, with energy efficiency in mind, and air movement practices will help reduce the effects of known and unknown reactants and their chemistry products. When the reactants somehow find a way to interact, the use of ventilation will help to reduce the time available (resident time) for the pollutants to react to form product(s). Air cleaning method, e.g. filtration, could also be used to reduce the amount of the reactants available for reaction. Thus, lowering the chemistry product(s) concentration. However, the filter should be maintained clean to ensure that chemical reactions that take place on filter surface are reduced as much as possible.
Do you want to know more about indoor air chemistry and its control? Read Carslaw et al. (2009), Weschler (2000) and Weschler and Carslaw (2018) papers.