After having very little luck with a digital formaldehyde meter to test indoor air quality I decided it was time to switch to a more proven way to do DIY formaldehyde testing. I did a lot of research and decided to try colorimetric gas detector tubes to measure formaldehyde levels which don’t require sending samples off to a lab. The most common way for homeowners to test formaldehyde levels is using a sampler which is placed in a room for 24 hours then sealed up and mailed off to a lab for analysis. Some of the home test kits have a test tube and an air pump which you run for about 30 minutes, these are more expensive tests and also require sending away to a lab. If you only want one data point then mailing off an air sample to the lab is more cost effective. I wanted quick results from measurements so I could make a change and see the impact without having to wait for a lab so a formaldehyde colorimetric gas detector tube was the logical choice outside of an electronic meter.
To use colorimetric gas detector tubes you need a few things; a gas detector tube for the specific gas you are testing for, an air sampling pump that can accurately meter a specific amount of air through the tube, a thermometer to make corrections to the formaldehyde detector tube’s reading. I went through a lot of trial and error trying to find a good low cost air pump, partway into this project I found the Public Lab formaldehyde testing article which is a great resource. In the Public Lab article they used a modified aquarium pump for their air pump which works well and the article helped me wrap up the details to get this test setup up and running. I wanted to expand upon the Public Lab article and go into more detail for anyone interested in doing VOC and formaldehyde indoor air quality testing using colorimetric gas detector tubes.
The air sampling pump, flow meter, and other miscellaneous parts I used can be sourced for about $70 which is a one time purchase. The Kitagawa 710 formaldehyde test tubes are about $135 shipped for a box of 20, the GASTEC 91PL tubes are $83 shipped for a box of 10. The cost per test excluding the one time equipment purchase is $6.75 for the Kitagawa 710 tubes (but requires a larger purchase price up front) and $8.30 for the GASTEC 91PL tubes. I went with the Kitagawa 710 tubes as I wanted to do more than 10 tests.