The impact of climate change on the usage of ventilation for healthy indoor air quality

Indoor Air Cartoon Journal, May 2021, Volume 4, #118

The purpose of ventilation usage is to reduce the ageing of indoor air. The success of ventilation delivery on indoor air quality, and by an extension, the indoor environment is believed to occur when indoor air contains air pollutants at a concentration that does not compromise human health and comfort, perception of the environment, and performance. Another believed determinant of ventilation delivery success is indoor air containing temperature and relative humidity (RH) at levels that support human health and comfort, perception of the environment, and performance. When these determinants are successfully achieved, usefulness is provided to occupants of the indoor environment.

Thus, the lack of ventilation or inadequate supply of ventilation to indoor environments will make indoor air age very fast and unfriendly to indoor occupants. This is a fact well established in the literature. Our everyday life activities also reaffirm the importance of using ventilation to improve indoor air quality and environmental quality. Unfortunately, the established facts on the importance of ventilation and the inherent benefits are not enough to motivate many indoor environments designers, owners, and facility managers to use ventilation in air-conditioned indoor environments, especially those in a hot and humid climate appropriately.  

It is not uncommon to find many air-conditioned indoor environments designed with inadequate ventilation rates. Even when designed appropriately, many owners and facility managers would not operate air-conditioning systems to deliver appropriate ventilation to improve indoor air quality. It is also not uncommon to find many owners and facility managers relying on 100% air recirculation without using ventilation at all. The practices are largely motivated by the need to save energy as much as possible and win green building awards.

What is the lesson from the industry practice? Educating the industry professionals and stakeholders responsible for providing healthy indoor environments on the usefulness of ventilation or developing ventilation solutions, focusing only on ventilation usefulness in improving indoor air quality, is not enough.

The focus of the education and ventilation solutions development should be on the value-oriented ventilation delivery. In practice, industry professionals and stakeholders focus, consciously or unconsciously, more on the value of ventilation delivery than just the usefulness of ventilation. Value delivery is the sub-conscious key determinant of success for ventilation supplied to indoor environments. Thus, education efforts and ventilation solutions development on usefulness alone will not cut it for designers, owners, and facility managers. So how is the term value different from usefulness?

Value of ventilation usage is the ratio of ventilation usefulness to investment costs or resources needed to achieve the usefulness. Energy consumption and other financial costs are investment costs. To maximise value, i.e., maximising the usefulness of ventilation supplied from invested costs, it is essential to understand the risk of not delivering or maximising it (value). An informed risk assessment can aid the required education and ventilation solutions development for value-oriented ventilation delivery. Risk is the multiplication of hazard and vulnerability.

Hazard is anything that can cause harm to the goal we intend to achieve. The goal here is the use of ventilation for healthy indoor air quality and environment. Vulnerability is anything that will cause liability in experiencing the harm caused by the hazard. Hazard, in the context of this article, is climate change. Examples of harm caused by climate change, especially in a hot and humid climate, are very high outdoor air temperature and humidity levels.

The high air temperature, caused by climate change, increases the capacity of outdoor air, used for ventilation, to accommodate more moisture from water evaporated from earth surfaces. This phenomenon increases the likelihood of having high indoor air relative humidity at a level that is not healthy for human health and performance. The high air temperature caused by climate change also increases large wildfire outbreaks and the rate of chemical reactions between existing air pollutants in outdoor air to produce more harmful air pollutants.

High energy and other financial costs are needed to condition and clean the outdoor air to a healthy level before being delivered to indoor environments. The high investment costs required, based on many solutions currently available in the market, will compromise the value of ventilation delivered into indoor environments. The fear of the required investment costs to deliver usefulness inherent in ventilation will increase resistance to the appropriate usage or provision for ventilation by designers, owners, and facility managers. Remember, “fear is stronger than love”. Replace that with fear of investment costs is stronger than the usefulness inherent in ventilation.

The deliberate reduction in the investment costs needed to condition outdoor air to a healthy level because of the fear of economic implications with little or no consideration for the compromise that would occur to the inherent benefits or usefulness of ventilation will also lead to low value-oriented ventilation supply. The moral of this is, do not compromise on the usefulness of ventilation, and for every additional investment cost, strive towards achieving more usefulness inherent in the ventilation supplied to the indoor environment.

The vulnerability associated with air-conditioned indoor environments can further increase the risk of not maximising or delivering value-oriented ventilation. Air-conditioned buildings or facilities located in a hot and humid climate, especially those near the equator, like Singapore, are more vulnerable. Such vulnerability is called vulnerability due to exposure to the presence of harm caused by a hazard (climate change). In air-conditioned buildings or facilities with constraints in investment costs (e.g., financial constraint) needed to condition the outdoor air to a healthy level, economic vulnerability occurs. The society’s preference for energy savings as much as possible to the detrimental to healthy indoor air, is an example of social vulnerability.

The complexity of a building or facility structure, variation in ventilation requirements for different spaces in a building or facility, or variation in indoor occupants’ needs will lead to the building or facility “physiological” vulnerability. The complexity would require creative and excellent design thinking to navigate the inherent challenges of maximising value-oriented ventilation supply. Building and facility structures located in hot and humid climates are vulnerable because many of the available solutions in the market and current industry practices make navigation a huge task to overcome. The difficulty in navigating the challenges will increase the “physiological” vulnerability.

The assumptions that healthy indoor air and environment cannot be achieved without high energy costs will hinder the thinking required to develop creative solutions and strategies for increasing value-oriented ventilation delivery. The assumption may also increase resistance to the use of ventilation in the face of persistent adverse effects of climate change. The hindrance caused by such an assumption from designers, owners, and facility managers will deepen the psychological vulnerability associated with air-conditioned indoor environments.

The increasingly adverse effect of climate change (hazard) in the presence of vulnerabilities mentioned above will increase the resistance to ventilation usage in the industry, thereby increasing the risk of low value-oriented ventilation delivery occurrence. The COVID-19 experience has shown the importance of using ventilation to improve the healthiness of indoor air and environments. It is believed that many industry professionals and policymakers are motivated to increase the usage of ventilation in their buildings or facilities. This newly found motivation may be lost over time if the focus continues to be solely on the usefulness provided by ventilation, with little or no considerations given to the development of new solutions or strategies for value delivery.

The development of solutions and strategies that will facilitate the use of ventilation where and when the indoor occupants need its usefulness for healthy living and work will reduce investment costs while usefulness is being maximised. The use of digital solutions that aid the effectiveness of defining indoor air quality problems and their causes will increase the maximisation of ventilation usefulness with prudent use of investment costs, i.e., value delivery. It is important to note that there is no absolute endpoint for value achievement. Reducing the sources of pollutants and their emission rates as much as possible will also reduce the unnecessary usage of ventilation and thus reduce costs. There will always be room for improvement. Thus, a continuous improvement mindset will be essential.

Policies given preference to the determinants of ventilation delivery success by industry professionals and stakeholders will increase the likelihood of sustaining the newly found motivation for ventilation usage in the industry. To sustain interests in ventilation usage, basic and applied research efforts are needed to develop solutions and strategies for adapting to the challenges of climate change and maximisation of value-oriented ventilation delivery. The suggested value-oriented ventilation delivery research efforts will require professionals of different expertise from the industry and academia to work together. Funding from government agencies and other funding agencies will be needed to support the research and education efforts.

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