Indoor Air Quality

What is Indoor Air Quality?

IAQ – short for ‘Indoor Air Quality’ – refers to the quality of the air we breathe indoors. Not only is having enough fresh air important, but the quality of indoor air also has a significant impact on the wellbeing and performance of those present.

Unfiltered, indoor air can be polluted with biological, chemical and combustion pollutants:

  • Biological pollutants: agents derived from living organisms, such as bacteria, molds, mildew, viruses, house dust, mites and pollen.
  • Chemical pollutants: chemical compounds emitted from everyday (cleaning) products, air fresheners, disinfectants, furniture and paint.
  • Combustion pollutants: emissions from indoor combustion appliances, varying from carbon monoxide, nitrogen dioxide and (ultra)fine particles to polycyclic aromatic hydrocarbons and formaldehyde.

Pollutants that cause us trouble include carbon dioxide (CO2), nitrous oxides (NO), carbon monoxide (CO), ozone (O3), particulate matter (PM), radon (Rn) and volatile organic compounds (VOCs) such as formaldehyde, benzene, etc. – which infiltrate through, among others, outside air, printers, furniture, carpeting, computers, cleaning products, paints, pollen and mould (humidity). 

Of the 82,000 commercial chemicals used, we know what the negative (effects) on our health are for less than 15% of these.

Pollutants enter our body both through inhalation and skin absorption. The most common physical ailments caused by poor indoor air quality are asthma, fatigue, irritation and headaches. In turn, these ailments contribute to a decreased feeling of wellness, diminished productivity and/or more absenteeism-related illness.

The US Environmental Protection Agency (EPA) has declared that the health risks posed inside are greater than those outside.

Why Clean the Air Indoors?

Air is comfort. Air is energy. Air is life.

90% of our time do we spend indoors. Knowing that indoor air can be up to 50 times more polluted than outdoor (or ambient) air, it is of vital importance that we clean the air we work and live in using the appropriate air purifying tools and systems.

The quality of the air we breathe has a direct effect on our health and performance. We purify the air not only to eliminate bad odours, but also to maintain a healthy working and living environment for the people we care about and count on.

Research confirms the importance of clean air

  • A Danish study (Wargocki, 1998) concludes that productivity increases by an average of 5% when sources of pollution are removed from the space (resulting in better air quality).
  • A study by Bakó-Biró (2004) on test subjects exposed to emissions from new computer equipment shows that these test subjects made 9% more errors.

Indoor Air Pollution: Facts

A whopping 80 million Europeans live in damp and unhealthy homes, an environment which doubles the risk of asthma. The long-term effects of polluted indoor air range from asthma and allergies to lower performance rates and even learning difficulties: 

  • As many as 30 million people suffer from asthma and allergies due to bad indoor air.
  • Every year 600,000 Europeans die from respiratory diseases.
  • Poor indoor air quality can affect the learning abilities in children as well as our general productivity.

A healthier indoor climate can successfully reduce the number of sick leaves in your company as well as improve the learning and productivity rates of your children and/or coworkers.

European Federation of Allergy and Airways Diseases Patients' Associations (EFA)

What is EFA?

EFA (European Federation of Allergy and airways diseases patients' associations) is an umbrella organisation, which at European level represents 39 national patients’ associations in 25 European countries.

EFA is dedicated to making Europe a place where people with allergies, asthma and COPD (Chronic Obstructive Pulmonary Disease):

  • have the right to the best quality of care and a safe environment
  • live uncompromised lives
  • are actively involved in all decisions influencing their health

Why is Indoor Air Quality important to EFA?

64 million students and 4.5 million teachers are affected by bad indoor air quality in Europe. Breathing is a prerequisite of life. Depending on regional culture and outdoor climate, Europeans spend most of their time in indoor environments. To breathe, healthy indoor air is therefore considered a fundamental right by the WHO (World Health Organisation).


Sustainability certificates

BREEAM (Building Research Establishment Environmental Assessment Method)

This assessment method determines the sustainability of buildings. It was developed and introduced by the English research body Building Research Establishment (BRE). The method is divided into five different standards: 1) Communities, 2) Infrastructure, 3) New Construction, 4) In-Use, 5) Refurbishment and Fit-Out.

LEED (Leadership in Energy and Environmental Design)

LEED is an assessment and certification system used to determine building sustainability performance. The method was set up in 1998 by the US Green Building Council (USGBC) and is the most widely used sustainability tool in the United States.

Wellbeing certificate


People – and not just sustainability and energy – are increasingly the centre of focus in the design of new buildings. The end goal is to guarantee the user’s wellbeing. It’s for this reason that the International WELL Building Institute (IWBI) introduced the WELL Building Standard in 2014, to promote healthy and sustainable buildings. It was updated in 2018 based on experience gained: WELL v2.

This performance-based standard measures, certifies and monitors the built environment and its effect on our health. In so doing, WELL strives towards designing buildings that make users healthier and happier. The air, comfort, sound and light quality are measured and improved based on personal needs. WELL, therefore, specifically targets the health and wellbeing of building users.

Trusted partner: SIG Air Handling

Expertise in improving indoor climates

As a leading air handling company with over 100 trading sites, HVAC expert (heating, ventilation & air conditioning) SIG Air Handling shares and utilises their expertise in improving indoor climates and energy efficiency to create a healthy and safe indoor environment for everyone

Indoor Air Quality has become a major concern for many people in Europe and all around the world.

– Lex Hemels, Group Business Managing Director Air Handling


We share our expert knowledge, explore innovative techniques and support like-minded organizations to put a stop to air pollution indoors. Through a strong customer focus, expertise, ease of access and reliability we are your solutions-oriented partner.

city drawing


Total solutions

SIG Air Handling takes care of solutions in the area of air filtration and fully integrated Smartwellbeing to ensure an optimal indoor climate (indoor air, thermal comfort, acoustics and light). Our specialists combine products, systems and services with advanced control technology and smart building technology (Smart Building). And that’s how we create a healthy living, work and residential environment that the user is able – based on his or her own needs – to help determine.

Over the past ten years, the amount of technology installed in buildings has gone up by at least 45%. (Building) technology is evolving at an increasingly rapid pace and is only becoming more complex SIG Air Handling keeps close track of the latest developments (national and international) and tests applications within different market segments. We never fail to keep the standards, requirements, legislation and certification systems for a healthy indoor climate in mind. 

Development and testing

Our experts rely on their experience for the (continued) development of new products and systems, services and project-specific solutions for every indoor climate issue.

In relation to climate, noise, control technology, performance, installation and assembly, SIG Air Handling has a wide range of testing facilities for this purpose. Where necessary, we also employ complementary techniques such as BIM/Revit, CFD, big data and 3D printing. 

Specific advice

Would you like advice about Indoor Air Quality or Smartwellbeing? Our specialists are eager to help with any indoor climate technology-related issues.

Please feel free to contact one of our specialists.



Smartwellbeing case


There’s a big difference between theory and practice. Would you like to see how Smartwellbeing is applied in a specific project? Take a look at the EDGE Olympic case: an inspiring workplace where smart technology, sustainability and wellbeing set the standard.

More resources

There are a number of great resources available for diving further into the world of Smartwellbeing.