The summer of 2020 has seen record wildfires in the Western US and in addition to being concerned about the direct threat of fire to our home and everything in it, we've suddenly learned how challenging it can be living with heavy smoke and haze as part of daily "weather". While it's easy enough to buy a good air quality measuring device, I couldn't pass up the opportunity to build one. In just the few days since I got it operational we've learned how important and helpful it can be knowing the quality of our air and being able to compare conditions at home with forecasts from local news, weather, and fire-fighting agencies.

If you're interested, I've written a longer article about the project, providing more details on the components used and some of the interesting (and unexpected) math needed to calculate AQI the way the US EPA defines it. Here's a plot of our measured air quality at home during an especially bad period earlier in September, with values into the "Unhealthy" and even Very Unhealthy" ranges: