Readings from a PurpleAir sensor, on a TRMNL ePaper display. Use your own sensor or any public one on the PurpleAir map. Enter its sensor ID and a PurpleAir API key, plus a read key if the sensor is private.

Choose what to show. Air quality gives you current PM2.5 and PM10, with a chart of the last 24 hours marked against the EPA air quality levels, from Good to Very Unhealthy. Temperature and humidity shows those 2 instead, in Fahrenheit or Celsius. We only ask PurpleAir for what changed since the last refresh, so your free API credits last a long time.