Impact of indoor climate on human health

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HOBEL posts

 Lucie Frésard, Maxime Dunod, Edouard Heinkel, Jordan Dessibourg

 

Motivation and process & Introduction

We selected this topic because we are all confronted with the indoor climate without knowing much about that. Moreover it has a major influence on our health knowing that we spend 90% of our time inside (1). Besides, we can’t ignore that there are generally 3 times more air pollutants inside than outside.

Just to give an idea: according to the WHO, in the world, 3 billion people still heat directly their home and food by burning fuel, biomass and coal (2). With bad ventilation, it results with a high level of air pollution, sometimes 100 times more than the acceptable limit, causing 3.8 million premature deaths per year because of pneumonia, CVA, lung cancer, … Worldwide, indoor (household) air pollution is one of the biggest health risk factors for humans.


Then, when we design buildings, we have to think about the indoor climate and it’s impact on human health.

There are many indoor air pollutants (3) :

  • pollution from outside (traffic, industries, grounds,..) depending on building’s outside air penetration ; carbon monoxyde, radon, ozone, oxide of nitrogen
  • construction/decoration materials ; Volatile organic compounds (formaldéhyde and others).
  • activity/behavior of users (aeration, cooking, heating, cleaning, smoking, lighting, appliances, pets, furnishings) ; oxide nitrogen, ozone, fine/ultra fine particle.

They can also be classed by nature : Inorganic gases, Organic gases, Particulate matter (PM)

 

Impact of indoor climate on Swiss Health

We can assume that sources of pollution are approximately the same in all western Europe countries. Therefore we focused on issues in Switzerland, we will assume swiss buildings will be affected by those factors.

Bad indoor climate is mainly causing (4)(5)(6) :

 

-Pneumonias : causes irritation of the lung walls due to the presence of PM10 and PM2.5 in case of a long term exposure and deposit. Pneumonias can also be caused by legionella bacteria sometimes present in humidifiers, decorative fountains and many other sources. 

 

-Heart Disease : caused by ultrafine particles on a long term exposure, these inhaled particles pass directly into the bloodstream through the lungs, vessels blood and cause local inflammation.

 

-Lung Cancer : Mainly caused by tobacco, both for smokers and their families that are exposed to the fine particles of the smoke (under 2.5 microns) that are deposited in the bronchi and lungs. The second main source is the radiation of radon (causes 200-300 deaths in Switzerland every year)(11), which is currently a big problem. We can as well quote lung irritation and allergies caused by molds and proliferation of dust mites when there is too much humidity. 

Radon comes from the disintegration of uranium existing everywhere in the ground. If the ground is permeable, radon can come to the surface and contaminate the ground floor (1). With the heating of the house, there is a little imperceptible depression on lower floors, and radon goes up in the house. It is worse in winter, when we heat a lot. The risks of lung cancer increase with the concentration of radon and the time spent in the contaminated room(11). 

 

– Strokes : Can be caused by fine particle associated with others factors, carbon monoxide prevents oxygen to attach itself to the blood and promotes cardiovascular disease 

 

-Fertility issues : Other health issues do exist such as fertility problems. They are caused by several factors, the PM10 that may come from the outdoor air in very polluted and congested cities, but also from indoor sources that is to say dust, caused by vacuuming, sweeping, dry dusting.(13) 

 

How to avoid health issues

In order to limit the effects of pollutants on our health we have to control the outdoor pollutants that come from infiltration, from the windows when opened, and through the mechanical ventilation (air conditioner for example). But also to control the pollution coming from the indoor sources. Individually, we don’t have any control (or very small) on the outside pollution, therefore there is no other choice than protecting ourselves against the danger. But we have a control on the indoor sources, then it is possible for us to limit the pollution and eliminate it. 

Most of the time, concentrations of most pollutants are higher indoors than outdoors. Ventilating your house is very important (1), but we have to be sure that the outdoor air is not more polluted than the indoor air, or may contain pollen that is a problem for some people. It can easily be controlled with official information.

In order to enhance the quality of our indoor air, we could purchase an air purifier but its efficiency hasn’t been proved in real condition (7), therefore trying to limit the source of air pollution seems to be the best way to have a good air quality and it’s cheaper.

We could stop using candles, we know that if the room is closed the amount of ultrafine particles can increase by 10% (7). The most important thing to limit the amount of particular matter is to stop smoking inside to protect the people living with us especially if we have kids.

Some of our devices that we do not suspect are as well responsible for the emission of ultrafine particles, like for example toasters, printers or photocopiers(1). 

One thing we often forget is the volatile organic compounds. Their sources are multiples (construction material, agglomerated furniture, painting), so we have to try buying things that don’t contain them, or avoid using perfumes or incense because they also contain VOC’s and particulate matter(7).


Regulating the humidity ratio between 40%-60% is a good way to prevent the nocive moistures that causes respiratory conditions (7). One way to do it is by having a good natural or mechanical ventilation. It’s important to remove humidity outside because it can cause multiple SBS: eyes irritation, asthma or bronchitis. Moreover, for people with an immune weakness it can be more dangerous because of the infectious potential.

It is necessary to take off the dust as often as possible because it carries pollutants, and if it is not removed it will go to the air because of Human activity and cause the problem we have seen (8).

 

To avoid contamination by radon, there are 3 possibilities (10): 

  1. avoid infiltration with a permeable protection, like waterproo concrete
  2. reject the radon before it penetrate the house with ventilation under the foundations
  3. evacuate it from the building with a mechanic ventilation

 

figure 1 : Three possibilities to avoid radon contamination (10)

 

Conclusion

 

Even if indoor climate has a big impact on our health, we saw that there exists a lot of ways to be sure to live in a healthy home.

But in the world, deaths caused by indoor air pollution affect much more the low and middle-income countries than it affects Switzerland. The situation is critical in Africa and Asia, where it contributes to approximately 6% of the total deaths(12). 

It is mainly because in poor neighborhoods, people use wood, charcoal or kerosene combustion for heating, cooking and lighting inside their poor ventilated homes. They didn’t have access to cleaner carburants or better cooking technologies. That represents approximately 40% of the global population.

 

References :

  • 1 : “Lecture 06, 07 and 08 Indoor Air Quality”,Course: Fundamentals of indoor climate, Dusan Licina, https://moodle.epfl.ch/pluginfile.php/2848327/mod_resource/content/2/Lecture%2006%20Indoor%20Air%20Quality%201.pdf, (2020)
  • 2 : “Pollution de l’air à l’intérieur des habitations et la santé”, WORLD HEALTH ORGANIZATION, https://www.who.int/fr/news-room/fact-sheets/detail/household-air-pollution-and-health, (8 mai 2019) 
  •  3 : “ Pollution intérieure”, WIKIPEDIA,
        https://fr.wikipedia.org/wiki/Pollution_intérieure, (2020)
  •    4: ” Effets sur la santé de l’air en milieu urbain”
    https://www.who.int/phe/health_topics/outdoorair/databases/health_impacts/fr (2020)
  • 5 : ”Les maladies liées au bâtiment”, OFSP, https://www.bag.admin.ch/bag/fr/home/gesund-leben/umwelt-und-gesundheit/wohngifte/wohngifte-und-gesundheitliche-beschwerden/gebaeudebezogene-krankheiten.html, (24.08.2018)
  • 6 : “Pollution de l’air à l’intérieur des habitations et la santé”, WORLD HEALTH ORGANIZATION, https://www.who.int/fr/news/item/02-05-2018-9-out-of-10-people-worldwide-breathe-polluted-air-but-more-countries-are-taking-action, (02.05.2018)
  • 7 : “Qualité de l’air intérieur”, LIGUE PULMONAIRE SUISSE , https://www.liguepulmonaire.ch/fr/preserver-les-poumons/qualite-de-lair/qualite-de-lair-interieur.html, (2020)
  • 8 : “L’impact de la qualité de l’air intérieur sur la santé et le bien-être”, INITIAL, Virginie Racapé, https://www.initial.com/fr/blog/limpact-de-la-qualite-de-lair-interieur-sur-la-sante-et-le-bien-etre/ (13 déc 2019)
  • 9 :”Marche à suivre en cas de troubles liés au lieu de travail”, OFSP https://www.bag.admin.ch/bag/fr/home/gesund-leben/umwelt-und-gesundheit/wohngifte/wohngifte-und-gesundheitliche-beschwerden/vorgehen-bei-beschwerden-an-arbeitsplaetzen.html, (24.08.2018)
  • 10 ”Indoor Air Pollution”,OUR WORLD IN DATA, Hannah Ritchie and Max Roser, https://ourworldindata.org/indoor-air-pollution, (24.10.2019)
  • 11 : “Le radon, c’est quoi ?”, OFSP, https://www.bag.admin.ch/bag/fr/home/gesund-leben/umwelt-und-gesundheit/strahlung-radioaktivitaet-schall/radon/was-ist-radon.html, (19.12.2019)
  • 12 :“La pollution de l’air est le fléau qui réduit le plus l’espérance de vie dans le monde”, FUTURA SANTE,
  • 13 :”Santé la pollution de l’air réduirait la fertilité des femmes”, Le Nouvelliste, https://www.lenouvelliste.ch/articles/lifestyle/sante/sante-la-pollution-de-l-air-reduit-la-fertilite-des-femmes-851117, 02.07.2019