Regardless of whether you hear about it the first time or call it by its abbreviated pet name IAQ, indoor air quality influences you every day. Knowing it better gives you a chance to act so you can feel and perform well. So, let’s talk about the basics! 

What is good indoor air quality? 

Because indoor areas accommodate people, we usually talk about the IAQ in relation to how it influences its occupants’ health, well-being, and comfort.1,2 Hence, good indoor air quality makes people feel energized, comfortable, and healthy.  
Poor indoor air quality, on the other hand, can cause anything from feeling sleepy or having a headache to respiratory illness, allergies, or even more serious long-term health issues.3,4  
To stay on the good side of things, it’s important to know the culprits most often responsible for lower air quality, namely, the indoor air pollutants. 


Common indoor air pollutants 

There are many sources of indoor air pollution, including any appliances burning fuel, smoking, household cleaning supplies, excess moisture, and many more.2 What might surprise some is that one of the most common pollutants is the CO2 in the air we exhale.  
Luckily, the CO2 is also easy to monitor. Since CO2 levels show how much air around us is exhaled, it is also a good proxy for assessing the risk of certain airborne disease transmissions like the flu. 

Fresh outdoor air contains about 420 ppm (parts per million) CO2. Indoors, CO2 can quickly build up with the exhaled air. When CO2 levels are above 1000 ppm, it is a good idea to ventilate by opening the windows or using the HVAC appliances in your household.

Find out more on keeping the air fresh and healthy in this article.



1 – Soreanu et al., 2013; van Ras et al., 2005.

2 – United States Environmental Protection Agency, Introduction to Indoor Air Quality, <>.

3 – The National Environmental Education Foundation, Camille Bridger, The Health Impacts of Indoor Air Quality, <>.

4 – BMC, Arja Asikainen, Paolo Carrer, Stylianos Kephalopoulos, Eduardo de Oliveira Fernandes, Pawel Wargocki & Otto Hänninen, Reducing burden of disease from residential indoor air exposures in Europe (HEALTHVENT project),  <>.

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