In the good old days of the 19th century, carbon dioxide levels of the air were measured in various chemical ways. Several methods required drying of the air first. This could be accomplished by leading the air through sulphur acid (H2SO4). However it appears that CO2 also dissolves partly in that process. Now, I'm sure that there are methods of estimating the amount of CO2 that dissolves this way and consequently, the magnitude of the induced error, something with a Bunsen adsorption coefficients. But I'm afraid I did not pay enough attention in highschool, some millenium or so ago. Anybody, who can help me out?