Description:The amount of carbon dioxide had been
virtually constant at 280 ppm
(particles per million) – i.e 280 gas
molecules per million air molecules
– the last ten thousand years. However
in recent years, this measured value has
been increasing rapidly at approx.
2 % per year.
Supplementary description:A high level of CO
in the air within a
room causes headaches, tiredness and
lack of concentration. The regulation on
concentration was established in
order to evaluate IAQ (Indoor Air
Quality). Normal atmospheric air in
so-called ‘clean air areas’ has a level of
360 ppm and approx. 500 ppm in urban
areas. The limit of 1,000 ppm
(“Pettenkofer Figure”) is still seen as
being adequate indoor-air quality, which
is especially important when regarding all
meetings and conference rooms, as well
as schools and open-plan offi ces.
As a guideline for school rooms in the
USA the limit of 1,000 ppm applies; for
workplaces the occupational exposure
limit is 5,000 ppm.