The amount of carbon dioxide had been virtually constant at 280 ppm particles per million ie 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 yeara high level of co 2 in the air within a room causes headaches tiredness and lack of concentration the regulation on co 2 concentration was established in order to evaluate iaq indoor air quality normal atmospheric air in so