Explanation Air-Quality and CO₂

What is air-quality?

Air-quality is a dimension for the quality of air indoors. A objective measuring parameter of air-quality is carbon dioxide. This transparent and inodorous gas is what humans exhale and it becomes more the older they are and the more they are physically active. Outside the carbon dioxide concentration fluctuates between 360 ppm in clean air areas and 700 ppm in cities. The advised maximum value for indoors is 1,000 ppm CO2, the limit for offices 1,500 ppm. This limit is reached quickly! Thus the carbon dioxide concentration increases in a recently aired office with 25 m2 space, after shutting the insulation glassed windows within an hour up to 2,000 ppm, if there are four adults. 

Why is the air-quality so important?

The air-quality influences the well-being of office workers. Carbon dioxide is only toxic above a concentration of 5 volume percentage (that is 50,000 ppm), but it causes at much lesser concentrations (values between 800 and 2000 ppm) unspecific obstructed health states like headache, tiredness, poor concentration and decline in output. Not only work tasks the a worker, but also poor air inside the office. Parallel to the carbon dioxide concentration, the air ratio of several other substances increases. For once there are odorants and messengers emitted by humans, then there might be evaporations of the room or the furniture that might add, e.g. formaldehyde, polychlorinated biphenyl (PCBs), cleaners and solutions. These substances might possibly harm your health (sick building syndrome), but their air-concentration is hard to determine compared to carbon dioxide.

How can the air-quality in a room be improved? Only by adequate aeration!

But putting this into practice might be difficult, since:
1.) Every human has an individual sensitivity for air-quality in a room. Those, who have recently entered a room filled of people, estimate the air-quality much poorer than those who sat inside for a longer term (acclimatization effect). 
2.) During winter saving heating costs is a main factor, especially with the current price for heating oil and gas. Therefore it is often neglected that poor air-quality decreases the performance of all present people.
3.) Due to energy saving restorations on most buildings the percentage of natural air, coming through slots and gaps has continuously diminished in the past thirty years. Most people do not know that today they must aerate even more often than before in order to achieve a constant climate indoors. 

How do you aerate adequately?

By opening and shutting the windows depending on the carbon dioxide concentration in the air. By that a consistent climate can be preserved indoors, and unnecessary energy waste is prevented. Since humans cannot percipience carbon dioxide with their senses, therefore a meter has to be enlisted, ideally our air-quality meter.