Introduction
Although Climate change is dating back to the ancient Greeks, it has become a global concern nowadays and has many impacts on our way of life. This phenomenon is defined by a global long-term change in the average climatic conditions (such as temperatures, precipitations or wind) especially caused by human activity that increases the level of carbon dioxide in the atmosphere. In the context of Indoor Climate, it can relate to Indoor Environmental Quality (IEQ) which describes all environmental parameters inside a building. In this topic we will talk about the indoor air quality and thermal comfort which can be affected by Climate change. IEQ is a very important matter because it has a major impact on occupant health, comfort and work performance.
This is a current topic and a challenge for our future: we are living and feeling the Climate change and even if we take severe measures now, it will continue over a few decades. In fact, a lot of buildings and technologies, such as HVAC, are not built to adapt to such big changes and that is a real challenge for engineers. Moreover, Climate change will not have the same impact on IEQ depending on the location. We have to adapt, transform or find systems in order to keep an adequate indoor climate and a good IEQ despite the climatic modifications.
Hence we can now wonder how Climate change will impact Indoor Environmental Quality.
Effect on humans and influencing factors in buildings
Impact of indoor climate on health and productivity is capital as we spend most of our time indoors. Climate change is already starting to rear its ugly head and its impact on indoor climate must eventually be taken into account. [4]
We have had more and more heat waves these past years and the trend not only keeps on going but may also intensify. The consequences being an increased mortality rate, notably in the elderly. The productivity may also be affected if the indoor temperature is outside the comfort zone.
Heavy precipitation and flooding might happen in frequency and magnitude for which buildings have not been designed for. Water can seep in buildings and cause dampness problems which have been linked with increased mold infestations. They can cause inflammatory response and pulmonary problems.
The opposite problem might occur in other parts of the world. Wildfires in Southern France and California may cause periods with high amounts of fine particles. Likewise periods of low precipitation allow spans of high concentration of particulate matter to occur, which can worsen present medical conditions such as asthma and even create new ones in case of chronic exposure. [5]
Energy-wise, we could think that economies could be made in warmer winters if we need less heating. But it has been estimated that in Switzerland, the needs for cooling in summer will overtake the savings made in winter [6] . In Europe, we can find the same trend: a greater demand in AC and a lesser in heating (figure 2). The global energy consumption will at best stay the same or more realistically increase.
Remedial actions – What can we do to improve the situation?
As we saw right before, there are many challenges engineers have to deal with regarding climate change.
The main issues will be the rising temperatures and increasing heat waves. In fact, heat waves are warming buildings and affecting our IEQ. We have to find ecological solutions since we don’t want to use enormous amounts of energy to just cool down the buildings with air conditioners. One important thing is that we have to eliminate leakage as much as possible. Indeed, during heat waves, we don’t want infiltration of hot air in our buildings. To be precise, less leakage doesn’t only mean more isolation, because the heat generated by the building occupants still has to be evacuated. Furthermore, it is really important to mention that we want to keep an adequate IEQ without consuming a lot of energy. Indoor climate and energy use often are in conflict, so it is essential to get rid of fossil fuels and to use more renewable energy like photovoltaics on the rooftops for example [7]. Indeed, climate change is increased by the use of fossil fuels so if buildings tend to be more “green”, they can use their own energy produced from their photovoltaics to ventilate and cool down rooms. [8]
In addition, wildfires across the globe will increase and air particles due to pollution in cities will become more common. We have to protect our indoor spaces against these thin particles to minimize the effects on our health. There is an easy solution to this problem which shouldn’t be too complicated to apply on HVAC systems. There already exist really good filters and therefore, we just have to design filters which don’t let pass all those thin toxic particles. Actual HVAC systems already have filters to prevent dust, pollen, etc; but with the increasing use of more dangerous aerosols, we should maybe review and improve those filters to keep our indoor air clean. Notice that we technically can’t seal a building totally because people enter and leave and there will always be some small leakages even if we don’t want them. Introducing air cleaners inside buildings and more advanced ventilation would help reduce contaminant concentrations.
To avoid dampness and mold, we should build our buildings with “new” materials which don’t allow the growth of mold and fungus infection. But here again, sealing air and duct leaks are important to prevent water intrusion and growth of moisture.
Conclusion
As you probably noticed while reading this post, climate change will have a critical impact on our future indoor climate. The increase of heatwaves and intensive precipitation periods will cause several IEQ changes: non-optimal temperatures, mold infestations, high fine-particles concentration… Detrimental health impacts of those phenomena are well-known. Moreover, an important amount of energy will be necessary to correct those impacts. The challenge is now to adapt, through new standards, IEQ in an ecological way: maximizing “green” and auto-sufficient buildings, developing more efficient filters, and using humidity regulation systems are three main axes to solve this problem. But we should remember that climate change will have a different impact depending on the location : miraculous solutions don’t exist !
Gaspard Guillhot, Noah Enzmann, Luan Morina, Léandre Guy
References
Pictures :
[1] Business Insider, “Striking photos show wildfire smoke turning the sky orange over San Francisco” – shot by Katie Canales (September 9, 2020): https://www.businessinsider.com/san-francisco-orange-sky-smoke-fog-wildfires-california-photos-2020-9?IR=T:
[2] Maryse Labriet, Santosh R. Joshi, Amit Kanadia, Neil R. Edwards, and Philip B. Holden, “Impacts of climate change on heating and cooling: a worldwide estimate from energy and macro-economic perspectives” (2013)
[3] increased from dampness and mold https://www.pulmonologyadvisor.com/home/topics/asthma/asthma-rhinitis-onset-increased-from-dampness-and-mold/
Links :
[4] Berkeley LAB, Indoor Air Quality – Scientific findings resource bank, “Climate Change” (2020): https://iaqscience.lbl.gov/cc
[5] Committee of the Effect of Climate Change on Indoor Air Quality and Public Health, IOM: Institute Of Medicine of the National Academy of Sciences: “Climate Change, Indoor Environment and Health” (2001)
[6] OcCC : Organe consultatif sur les Changements Climatiques, “Les changements climatiques et la Suisse en 2050” (June 2007): http://www.occc.ch/pdf/855.pdf
[7] Prof. Dusan Licina. (2020). Introduction, 17.09.2020, Fundamentals of indoor climate, BA3.
[8] William Fisk, “Climate Change, Energy Eficiency, and IEQ: Challenges and Opportunities for ASHRAE” (June 2009): https://eta-publications.lbl.gov/sites/default/files/lbnl-2036e.pdf
[9] Featured image : Research on what “global warming” and “climate change” mean, and when to use the terms https://journalistsresource.org/studies/environment/climate-change/research-global-warming-meaning-use-terms/