Indoor Air Cartoon Journal, April 2021, Volume 4, #117
The successful reduction of the risk of health problems occurring due to exposure to air pollutants in the indoor environment is the purpose healthy building or indoor environment professionals, policymakers, and indoor occupants should strive to achieve.
The ideal success determinants are no impact of indoor air on physiological and psychological conditions and no impact on the indoor occupants’ work, learning, or living performance when they are present or after leaving the indoor environment in question.
Getting close to the ideal situation is what professionals and policymakers in charge of delivering healthy indoor air and environments and occupants should always work towards.
The reason for having this purpose is the discomfort and inconvenience air pollutants can cause to humans and society. The discomfort and inconvenience could lead to death or cause social and economic problems to people, organisations, and society involved.
A defined purpose answers the “what?” question. The reasons behind the defined purpose answer the “why?” question. The next question is, “how?” How to get to the purpose? How to maintain the achieved purpose? Understanding and appreciation of the “why” of the “what?” motivates the need to embark on “how?” and invest in it.
The first “why?” question is the “why?” of the “what?” question. The second “why?” question that should be asked is the “why?” of the “how?” question. The “why?” of “how?” question is crucial because how something happened is different from why it happened.
The “why?” of the “how?” provides answers to what should be done or have been done to ensure the achievement of the purpose or provide answers on best practices that should be encouraged or enhanced for better and successful achievement of the defined purpose.
To decide how to progress with the “how?” question, understanding risk assessment is essential. Hazard and vulnerability are the two broad determinants of the level of risk involved. In the context of the topic of this article, a hazard is an air pollutant. Air pollutants in focus are volatile organic compounds (VOCs). However, the discussion in this article can be adapted to any air pollutants.
Indoor occupants will be vulnerable if they are exposed to the VOCs. Vulnerability will increase depending on the duration of exposure, and the severity of VOCs occupants are exposed to in the indoor environment. Hazard, irrespective of its severity level, is harmless to humans when they are not exposed to it.
For harm to humans caused by a hazard to occur, they have to be exposed to it. That is, if there is no exposure to hazard, there is no risk of harm occurring. Thus, exposure is the first form of vulnerability. Knowing one’s exposure level to a hazard and associated risk level is essential. Without such knowledge, continuous exposure to the hazard may ultimately lead to death.
Other vulnerabilities that will lead to an increase in the risk, but not the focus of this article, are the exposed person’s physiological and psychological conditions and the social and economic conditions the exposed person.
There are indoor and outdoor sources of VOCs indoor occupants are exposed daily. Human activities are the primary sources of the VOCs generated in indoor environments. The generation of VOCs transported from outdoor to indoor environments is due to human activities, nature, or combination.
In an air-conditioned building with a good filtration system and low infiltration rate, outdoor to indoor transport of VOCs will be minimised. In such a situation, VOCs’ major contributions to indoor air will be human activities taking place in the indoor environment.
According to findings in Guo et al. (2003) study illustrated in the comic strip, housewives and cooks and food service workers were estimated to have higher cancer risk due to 8-h average daily VOCs exposure in indoor environments, respectively, than office workers and school children.
School children that studied in the air-conditioned classroom were found to have the least risk. Housewives, assuming they cook a lot, and cooks and food services workers can be exposed to several VOCs generated from cooking activities predominantly in their activities.
When a kitchen is not well ventilated, the concentrations of VOCs the occupants(s) of the non-ventilated or inadequate ventilated kitchen are exposed to will be significantly high (see article 116 for details). However, the emission rates of VOCs are traditionally lower in offices and classrooms compared to kitchen environments.
Thus, it is not surprising that Guo et al. (2003) found the risk of cooks and food service workers to be two times greater than that of office workers. They found the risk of working in the kitchen environment to be two times greater than studying in an air-conditioned classroom.
They found that the risk in home living room, with predominant smoking activities, was one-to-two-degree greater than other indoor environments studied. See the comic strip for details. Smoking activities do generate several VOCs that increase the risk of cancer occurrence.
The risk of bus riders was found to be greater than those travelling by mass transit in the study. The risk of bus riders can be expected to be higher in countries where emissions from vehicles are not controlled or well-controlled. The outdoor to indoor transport of VOCs into the buses, especially if they have high infiltration rates, is expected to be high.
They also found that the risk in restaurants was higher than risks in non-smoker’s home, office, printing room, and air-conditioned classroom. This finding reiterates the role of cooking activities to VOCs generation. However, risks in restaurants studied were lower than the risk in smoking home. The observation reaffirms the role of smoking activities in VOCs exposure and risk of cancer occurrence.
Elevating the protection level as the risk level increases is thus essential. Without the awareness of the risk level, the provision of appropriate protection might be inadequate or absent. How should protection be done?
One form of protection is for humans to avoid indoor environments where the VOCs exist. This is not a realistic solution in many cases, especially for instances addressed in this article.
Thus, the realistic protection in these instances is source elimination or reduction and purification (ventilation, filtration, and cleaning) of the media (indoor air and indoor surfaces) through which the pollutants are transported in the indoor environment. Another form of realistic protection is through prevention or reduction of inhalation, dermal uptake, and ingestion of air pollutants where applicable.
When the protection takes place and actions taken are important to reducing the risk of health problems occurrence and fulfillment of the determinants of success for risk reduction. Thus, protection should be examined from the lenses of “before and after the health problem occur”.
Knowledge on why health problem(s) could occur is essential for the “before a health problem occurs” phase. Knowledge on why a health problem occurs and could occur is essential for the “after a health problem” occurs.
The knowledge in both phases is rooted in risk awareness, i.e., the awareness of how hazard and vulnerability will determine the risk. The risk assessment should be guided by the defined purpose and its success determinants.
When in the “before a health problem occurs” phase, appropriate actions taken based on the appropriate risk assessment done will reduce the gap between the current situation and a perceived better future state of fulfilling the defined purpose and its success determinants.
Inappropriate actions taken at this phase on the outcome of appropriate or inappropriate risk assessment done will increase the gap between the current and future states. In between, the possibilities of taking inappropriate actions should be part of the risk assessment.
At the “after a health problem occurs” phase, the most important thing is to learn from the failure of not achieving or not effectively achieving the defined purpose and its determinants.
When a health problem occurs, use the learning points from the failure to achieve the defined purpose to inform taking appropriate risk assessment to achieve the defined purpose or move closer to it as much as possible. If there is a failure to learn from the failure, the gap between the current and (preferred) future state will widen.
Fundamentally, doing appropriate risk assessment based on the defined purpose and determinants of its success is the beginning of winning the battle. Doing appropriate risk assessment will give the direction of how to get to the defined purpose and its success determinants. It will also provide the direction on how to maintain to sustain the defined purpose and its success determinants or provide room for continuous improvement.