Recently I purchased what is probably the best thing I’ve purchased in ten years. It’s an air quality monitor (AQM), that measures the formaldehyde, tVOC, and particulate content of the air I breath. These are things we’ve never worried about. For that matter, it didn’t matter whether or not we worried about them, because we had no reasonable way to measure them. For the past three years or so, new technology sensors have allowed for inexpensive AQM monitors in the $100 range.