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The first objective of a ventilation system is to ensure good indoor air quality, replacing stale air with fresh air from outdoors. While indoor pollution – a result of emissions from the human metabolism, indoor activities, and building materials and furniture – is a complex of many types of pollutants, humidity plays a remarkable and specific role in the residential context.

indoor pollution sources

Humidity: a decisive factor for a healthy building and occupants

Whether in liquid or vapour form, water is a leading cause of harm in dwellings. Small quantities of water vapour are enough to cause direct and indirect effects on a building and its occupants’ health.
While some moisture is essential for the correct functioning of the respiratory system – ideally between 40 % and 60 % relative humidity -, too much moisture is bad for a building and for its occupants. In new or thermally renovated buildings, a lack of ventilation associated with better insulation and better air-tightness can cause significant damage by allowing condensation to form on thermal bridges, glazing, and the vapour control layer on the insulation, and also cause deterioration of the insulation inside walls.
Most of this excess moisture is produced by human activity: water vapour from simply breathing and evaporation from domestic chores (washing, cooking, drying clothes, etc.); even indoor plants, if there are enough of them, can add to relative humidity.
More information on mould and dampness in European homes in a Fraunhofer IBP study and in the related infographic. In their conclusion, they state that “Enabling easy natural, automated or mechanical demand related ventilation in buildings helps prevent development of damp and mould“.

indoor pollution sources

A high relative humidity favours bio-contaminators

A high relative humidity in indoor air increases the risk of infestation by dust mites and creates condensation on cold surfaces, favouring the proliferation of fungi and bacteria. The relative humidity in a dwelling must therefore be effectively controlled by an effective ventilation system and stabilised at a suitable level.
In addition to humidity, shown to have a decisive role on the health and comfort of the dwelling, CO2, VOC’s, and other bio-contaminants have to be included in ventilation strategy to ensure good indoor air quality.

indoor pollution sources

The Volatile Organic Compounds (VOCs) and the Semi-Volatile Organic Compounds (SVOCs)

Studies carried out in countries throughout the world have shown that, especially when ventilation is deficient, many pollutants including the VOCs and the SVOCs are present in our dwellings at levels significantly higher than existing standards and WHO recommendations allow. The substances in question include paint, wallpapers, vitrifying products, laminated floor coverings, polishes, aerosol cans, kerosene stoves, and perfumes – among others.

This overexposure to those hazardous substances can cause devastating outcomes to health, especially to the most vulnerable persons meaning the new-borns and the elderly. Indeed, all the VOCs are classified as carcinogenic by the IARC, the International Agency for Research on Cancer. The SVOCs are larger sized VOCs. Therefore, they are less volatile, but they are not less harmful. In addition to a rise in cancer risk the VOCs and the SVOCs, which are specific indoor air pollutants, can cause allergic reactions, have neurotoxic consequences and disrupt the hormonal system. Indeed, some of those carcinogenic substances are also endocrine disruptors.

By ensuring permanent ventilation at a variable rate that is never null, Aereco ventilation systems are an appropriate answer to the issue of the VOC and the SVOCs. Combined with the right choice of low-emission furniture, materials, etc., our ventilation system limits the risk of exposure to these pollutants.

indoor pollution sources

Carbon dioxide (CO2) and other pollutants

The presence of CO2 in a dwelling is mainly due to people breathing. Studies show that breathing is accompanied by water vapour emissions, confirming the utility of using humidity controlled devices to manage the ventilation rate.
Among the pollutants found in dwellings that may be health hazards, those of most concern are: carbon monoxide, produced by heating systems, cooking with gas, and smoking; radon; asbestos; nitrogen oxides (NOx) and nitrogen dioxide (NO2). Other high-risk contributors include bio-contaminants such as dust mites, microbes, mould, etc.

There is only one way to effectively evacuate all these pollutants: ventilation. It is a vital need and an essential requirement for good health.

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