can you backup that statement?
I work at a growshop and we did a little experiment about it when co² injection was a trend under growers. 2 growcabinets, one with additional co² injection and one cabinet with a proper ventilation system, both under the exact same conditions and climate. The cabinet with the co² injection had a lesser yield and smaller plants. We suspect that the cabinet with the proper air ventilation had a better yield because of the thicker stems a plant produces when adding a better draft in a growroom.

The co² tables are avialeble at aquarium shops, they use it for better growth of water plants. Don't ask me how but it works like a charm, only downside is that it raises your sodium levels a bit in the water. Not very bad for the plants but when you use a EC meter it wil be off one or two tenths.