Measurement of low-level airborne 14CO2 in the environment using passive sampling

Passive sampling systems have been developed for sampling airborne 14CO2 using solid state absorbents. Absorbents included pellets of Ca(OH)2, mixed Ca(OH)2/NaOH and mixed Ca(OH)2/NaOH/microthene. Mixed Ca(OH)2/NaOH/microthene pellets placed in shallow containers sample at a constant rate over periods up to a month. Designs for passive diffusion samplers for longer term sampling have been studied by exposing pellets of absorbents for periods up to 1000 h. A weather enclosure has been designed to protect the samplers from the elements.