A simple system for measuring CO2 in air using glass sample tubes fitted with Buty rubber Suba-seal stoppers is described. A 1 ml aliquot is taken from the tube and is injected directly onto a gas chromatograph. The sample tubes and stoppers were adequately leak proof to CO2 and can be sent through the post to a central testing laboratory. The system has applications in agriculture and air conditioning studies and was used to measure the CO2 level in the air in glasshouses, a poultry unit, a conference room, an aircraft, and in other locations.
