Measuring gas concentrations

Dr Katja Riedel of NIWA explains that the air collected from the ice cores contains a mixture of different gases, and she describes which techniques are used to separate and measure them.

Transcript

DR KATJA RIEDEL The gas chromatograph helps us to measure the concentrations of our different gases. So you put a whole air sample in the front, and then out comes the different gases separated by time. How that happens is they travel at different speeds because they all have tiny little differences in, in their way of sticking to a medium. So some of them stick more and they travel faster, and other ones are less sticky and they come out first out of our gas chromatograph. And that’s a way of really separating gases.

Our gas chromatograph is there for measuring carbon dioxide, methane, nitrous oxide and carbon monoxide. And this is what we are interested in. These are the main greenhouse gases we want to measure.