How clean is the air that we breathe?
Most people spend more than 20 hours a day indoors. During this time, an average person drinks around 3 l of water and eats 1-2 kg of food. Considerable attention is given to what kind of food we eat, but the fact that each person breathes 15 kg of air each day is something that not so many of us concern ourselves about.
What is VOCs?
VOCs stands for volatile organic compounds. There are approximately 5 000 – 10 000 different Volatile Organic Compounds (odours, etc.) out of which the VOCs sensor detects almost all or at least typical representatives from each group, plus typical gases like carbon monoxide and hydrogen (both from combustion) as well as methane.
What are sources of VOCs in buildings?
There are two main indoor air contamination source. One is us, as people and human beings and occupants of buildings. And the second type of source are building materials, furniture, office equipment and consumer products.
Typical people´s emission sources are:
- breath, with typical substances CO2 and humidity, and also VOCs such as: acetone, ethanol and isoprene
- skin prespiration and transpiration, which typically has humidity, and also VOCs such as: nonanal, decanal and alpha-pinene
- flautus with VOCs such as methane and hydrogen
- cosmetics with VOCs such as limonene and eucalyptol
- househould supplies with VOCs such as alcohols, esters, limonene and unburnt hydrocarbons
- combustion (engines, appliances, tabacco smoke) with substances such as CO, CO2 and humidity
Typical building materials, furniture, office equipment and consumer products have emission sources from:
- paints, adhesives, solvents, carpets with typical VOCs such as formaldehyde, alkanes, alcohols, aldehydes, ketones and siloxanes
- PVC with typical VOCs such as toluene, xylene and decane
- printers/copiers, computers with typical VOCs such as benzene, styrene and phenole
How to get rid of VOCs in buildings?
The first group of emission sources (produced by people) and their respective VOCs can be handled by demand controlled ventilation (DCV) in buildings. And second indoor air contamination sources (produced by building materials, equipment and products) needs to be solved by 5-10% pernament ventilation in buildings.