Indoor air quality has an enormous impact on man, especially in the work space where he spends most of his day. The Commission of European Communities has been dwelling on this subject for more than two decades and has created guidelines for optimum ventilation in buildings.

Most regulations have been drawn up to identify and control, remove or simply dilute pollutants emitted to the air by the occupants of buildings but recent research has proven that existing guidelines have not taken into account building materials sometimes more polluting than man or his activities.

Two requirements are fundamental for indoor air quality:

  • Health risk should be negligible
  • Air should be fresh

Most individuals react differently to the same air quality and their level of sensitivity varies from person to person, so the gauging of human comfort in this case must be geared to indoor air being treated in such a way that it becomes a negligible health risk to occupants.

This is done through adequate ventilation of internal spaces.

To limit health risks, permissible concentrations of pollutants have been determined and exposure to these should be kept to a minimum in:

  • Industrial premises exposed to chemicals
  • Office premises exposed to pollutants from building materials, office equipment, and furniture
  • Gases
  • Humidity
  • Micro-organisms

Radon is a radioactive gas that can be found in indoor air if there is soil gas under the building capable of infiltrating into the inside through cracks in the foundations and other openings in floors and walls in contact with the terrain.

Ventilation of the subfloor spaces can eradicate these and other gases which also come from waste disposal sites, along with toxic chemicals, such as ethers and hydrocarbons.

Carbon monoxide generated by incomplete combustion from malfunctioning heaters or stoves or from infiltration of combustion gases from garages as well as unvented water heaters is, along with nitrogen dioxide, another common polluter[1].

Formaldehyde is another gas found in office situations and may occur as emission from particle boards with resin-based adhesives found on chipboard and foam insulation and may cause irritation to the eyes and lungs.

High humidity and condensation encourage the growth of mould and fungi causing allergies and help release formaldehyde from materials and low humidity causes dryness and skin irritation and ventilation is essential to avoid both cases.

Micro-organisms such as bacteria and viruses can come from badly maintained humidifiers and water systems and can be eliminated by controlling moisture levels[2].

In order to minimise these risks, ventilation must be provided and the quality of outdoor air must also be taken into consideration to ensure it is fit to be drawn into the building; otherwise it will be necessary to clean it at the ingress point.

Air flow from pollutants areas such as toilets, bathrooms and kitchens should be taken out of the building as soon as possible by maintaining these areas under pressure and equipment such as air coolers, fans, heat exchangers, air ducts and outdoor air intakes should be kept clean at all times.

And, of course, as a first and very simple measure, you can always resort for help to our good old friends the plants which can get the best Purifying Scores around.

Look at Areca Palm rated 8.5 in 10 by NASA and labelled as “the top air purifying air humidifier”[3] around capable of keeping you moist and toxin-free during summer seasons and of replacing all together your unsightly electric humidifiers in winter!


Image source: Areca Palm –

By Silvia Pelham

[1] European Concerted Action Report No. 3 “Indoor Pollution by NO, in European Countries”

[2] European Concerted Action Report “Strategies for Sampling Biological Particles in Indoor Environments”.

[3] By such as MetaEfficient –