How does Peter van den Berg graph his stove emissions?

Hi everyone,

In a recent video published by Paul Wheaton (skip to 3 min 02 sec) we can see a graph of emissions from a stove. How are these measurements taken? I don't need real specifics, just interested to know if it's something I could replicate myself.

Peter has a professional grade "testo" meter which costs in the neighborhood of $1000... not a general hobbyist item I'm afraid.

IIRC, it's a testo 330-II

You can find these on secondhand sites for may be 600 dolls.  Or far cheaper, if the CO and O² sensors are shot.

Thank you both of you for your help.