Review on 🏢 Detect Formaldehyde Levels Indoors with America's Leading Formaldehyde Generation Testing by John Swain

This gives very rough readings for formaldehyde. You will definitely know if you are at a very high level. However, at lower levels, it's difficult to distinguish different readings because the color changes are very subtle. Just look at the color charts and you'll see what I mean. Don't expect to be able to determine the level very accurately. Still, I'm glad I took the test. He told me that although I had some formaldehyde, the level was not in the dangerous range.