Abstract
The technique for high quality measurements of the atmospheric CO2 concentration has been developed by improving many facets of the commercial nondispersive infrared CO2 analyzers. The precision of better than ±0.05ppm was attained for both continuous and flask-sample analyses. The standard gases of CO2-in-air mixture have been prepared by the gravimetric method using an extremely precise balance; the absolute accuracy of the CO2 concentrations were estimated to be better than ±0.3ppm. The problems of great importance in the flask sampling technique, i.e., possible deterioration risk of air samples stored in the flasks and effect of water vapor condensed in the sample flask on measured values of the CO2 concentration, have been examined.
