The Impact of Indoor Air Quality on Health

2020 changed the way we think about our homes, offices, schools, shops and other private or public spaces that we share.

With the development of the Covid-19 pandemic around the world, the way we socialise, work and utilise our free time has had to adapt.

One of the most significant changes was the increase in the time people spend indoors.

In 2019, it was already predicted that people spend an average of 90% of their time indoors, and then we experienced national lockdowns, the shift to remote working, and self-quarantine recommendations. This resulted in an increased interest in indoor air quality (IAQ). If you’re currently working from home, check out our tips on how to set up the ideal home office.


Amid the protocols being issued to protect us, the topic of indoor air, air pollution, its quality, and how it impacts our health gained traction. It has since become a concern for many, equally at home, in educational facilities, and for all manner of businesses. 


But though we hear that poor indoor air quality has negative effects on health, it’s not easy to understand how or in what ways it affects us. For example, did you know that high temperatures in an enclosed space decreases our willingness to socialize or participate in activities?



What are Some of the Ways that
Poor IAQ can Affect us?


To answer this question, we’ve taken a look at specific themes or scenarios that we are familiar with:

General Health - Pollutants in the air can set off allergies and even lead to the development of new ones. Headaches and respiratory issues are common symptoms of poor IAQ but research has also linked life-threatening conditioners like cancer, diabetes and organ damage to overexposure.


In schools - IAQ in schools directly affects a student’s ability to learn and their academic performance, as shared by IZA World of Labor, and puts attendance at risk if conditions don’t improve.


At the office - A study by Ambius highlights that 1 in 2 office workers in the US lack focus because of bad air quality and that 40% of workers suffered illness as a result of poor air quality in the workplace. 


Pets - Just like humans, our pets can develop breathing-related issues and diseases in households where poor ventilation and pollutants are present. On the other hand, pets negatively impact the air you breathe at home so measures need to be taken to protect both you and your pets


In the gyms - During peak hours, gyms experience a surge in carbon dioxide, especially in group classes (spinning and yoga), as well as an increase in dust and other debris circulating. Also, changing rooms are perfect for molds and other bacterias to grow if poor ventilation and improper management of humidity levels is present. 


Generally speaking, when a person suffers from one or more symptoms of poor IAQ, like headaches or respiratory problems, it is known as having sick building syndrome (SBS). The term is mostly associated with symptoms developed in office spaces but SBS can be developed in any building. And when we are talking about indoor air quality, we are also talking about indoor air pollution. 


 How indoor air pollution can affect education and concentration


How Does Indoor Air Pollution Affect me?


The symptoms that are related to sick building syndrome are varied, just as are the ways in which inadequate IAQ affects each person. We’ve mentioned headaches and problems with concentration, but what other symptoms can you develop after spending a few hours within an enclosed space with poor air?

  • Trigger allergies 
  • Irritated eyes, nose or throat
  • Blocked nose
  • Dry, itchy skin
  • Tiredness
  • Rashes
  • Dizziness
  • Nausea

In most cases, symptoms will cease shortly after leaving the space in question. However, overexposure or repeated exposure can impact negatively on existing health issues or lead to others.



What Causes Poor Indoor Air Quality?


There are many factors that contribute to poor IAQ, in enclosed spaces. There are gaseous pollutants and then particulate matter pollutants (PM). Both are equally as harmful in concentrated amounts: a buildup of carbon monoxide can lead to death within a short amount of time, and particulate matter like microscopic plastic fibres can enter the lungs and lead to health complications. 


Of the gaseous, one of the main sources is a group known as volatile organic compounds or VOCs, which are gases emitted from many common products. These include: paints, paint strippers and other solvents, wood preservatives, aerosol sprays, cleansers and disinfectants, moth repellents and air fresheners, stored fuels and automotive products, hobby supplies, dry-cleaned clothing, pesticide, some furnishings and building materials. Source -


entilating enclosed spaces to help indoor air quality



Other sources of gaseous and particulate matter pollutants: 

Pets -
pet dander is the microscopic pieces of skin that comes off our pets when they shed their hair, triggering allergic reactions in people. Dander can also contain animal saliva, urine and feces which can cause further reactions.


Carpets - though useful for trapping dust and allergens and reducing their circulation, it also means that these pollutants are harder to remove and build up over time, particularly in older carpets. Whereas new carpets can release gases and fine fibres which can affect us equally.


Open fires and candles - any combustion source has a negative impact on IAQ but wood fire burners and open fire sources, and candles reportedly release more gases compared to gas burners as well as fine particulate matter like smoke.


Gas stoves and burners - numerous pollutants are emitted from gas stoves, with carbon monoxide CO being the most renown. A buildup can lead to dizziness, nausea and even death. Long-time exposure to small amounts impacts on existing cardiovascular health issues. 


Humidity - If humidity levels are too high damp is likely to form, leading to mildew and mold. Not only does it look grimey and smell unpleasant, but mold spores lead to an increase in asthma, coughs and more.  


Outdoor sources - Let’s not forget that there are outdoor sources that can be brought inside and accumulate over time. These include dirt, pesticides, car pollution and radon (a radioactive gas that comes from soil and rocks).


The pandemic meant that habits changed and not only are we spending more time indoors and more time in one location, but fortunately there are ways to protect and improve IAQ wherever you are. 


Keep track of indoor air quality at home and in the office


How is Indoor Air Quality
Tested & Measured? 

Measuring gas pollutants can be achieved by installing an indoor air quality tester, which offers real-time readings of the quality of the air around you and the concentration of moulds, humidity, VOCs and other gases. 


Many air quality testers will also have the ability to measure particulate matter in the atmosphere.


As a standard, they are designed to detect two types of particulate matter; those that are 10 um (microns) in diameter, which are likely cause irritation to the eyes, nose and throat but are too harmful on the lungs. Fine particulate matter that can easily enter the lungs and cause damage is measured at 2.5 um (microns) in diameter.


These fine particles can travel deeper into the lungs and even enter the bloodstream, especially when exposed to large concentrations over long periods. 



Ventilation as Part of the Solution

Proper ventilation of the space is one of the easiest ways to improve the IAQ. By opening windows or using an air renewal system, indoor air is diluted with fresh, outdoor air. This is particularly important to do so in buildings that effectively seal, stopping any outdoor air entering. There are some trades and home activities that are best performed with an open window or ventilation system to protect occupants. Buildings for schools, gyms and offices also need to implement certain protocols to ensure that ventilation of spaces is performed regularly to avoid poor productivity and build-up of odours and moulds. 


How to Reduce Indoor Air Pollution

As well as ventilation, there are various actions that can be taken to reduce the concentration of air pollutants, both gaseous and particulate matter.

  • Ventilation - as highlighted above, all enclosed spaces should be ventilated regularly, especially gyms, industrial facilities, kitchens and schools where we are exposed to various pollutants in greater concentrations.
  • Plants - The infamous Clean Air Study by Nasa says that having plants in enclosed spaces ‘cleans’ the air by absorbing harmful gases. 
  • Habits - Avoid smoking in the house
  • Burning - as cosy as they might be, lighting candles, wood burners and open fireplaces should be kept a minimum
  • Air conditioning - Use your air conditioning system to keep humidity levels low and manage indoor temperatures, both of which can elevate the presence of gases and PMs. Air conditioners also feature specialized filters that can help improve IAQ, too, something which Hitachi Cooling & Heating offers with some of our models.


The best AC technology for improving indoor air quality


Advanced Solutions by Hitachi Cooling & Heating

We specialise in efficient climate control solutions to help our customers manage and maintain exceptional comfort in the spaces they need to. Within our ranges, we have developed technologies that promote cleaner and healthier air.


Wasabi Air Purifying Filter is a PM 2.5 filter that provides powerful antibacterial(1), anti-allergen(2), anti-mould (3), and deodorising(3) properties when combined with the Hitachi Cooling & Heating standard Stainless Steel Pre-Filter (4), and can remove up to 99% of the most common bacterias, particulate matter and allergens, as well as bad odours.


UV Fresh emits shortwave ultraviolet light onto the filters from an internal LED, neutralizing 99%(5) of bacteria trapped on the filter to keep the inside of your unit clean and reduce the risk of odours.


FrostWash™ minimizes the amount of dust, mould and bacteria that build up on your air conditioner’s heat exchanger and reduces their presence inside your unit by up to 93%(*6). It traps the dust and dirt that lands on the heat exchanger by freezing in moisture that’s generated during normal operation. The frost is then thawed and flushed hygienically out the unit, carrying the dust, mould and bacteria with it. Learn more about FrostWash™ here.


With the need to take better measures to monitor and improve indoor air quality, you can take the steps to ensure that the spaces you live and work in are as healthy as possible.  And next time you feel ‘off’ when spending too much time indoors, take a moment to ask yourself if you could be suffering from sick building syndrome. 


To learn more about our ranges and products, visit our home page to see how you can benefit from Hitachi Cooling & Heating. 


1 Wasabi Air Purifying Filter tested by University Putra Malaysia.
2 Wasabi Air Purifying Filter tested by International Medical University Malaysia.
3 Wasabi Air Purifying Filter tested by Nanopac Testing Lab.
4 Stainless Steel System tested by the Hitachi Environmental Test Laboratory.
5 UV Fresh tested by Japan Food Research Laboratories.
6 Used model:RAK-35RPE / RAC-35WPE Tested by Kitasato Research Center of Environmental Science. Test No. 2019_0154: Reduction effects of Bacteria and Mould were observed by operating FrostWash™ once.



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