Air Quality Monitor, Formaldehyde Detector - Real-Time Pollution Meter for PM2.5/PM10, TVOC - Temperature & Humidity Sensor - Indoor/Outdoor Air Tester for Home, Office, Car

Easy to use and good (USB charged) battery life. Device displays Air Pollution Level summary from 000 to 100 (a standard superseded in 2013 by Air Quality Index rating 000 to 300, which encompasses additional data) but will still tell you what you need to know with regard to common chemical and particulate irritants as well as recording time, temperate and relative humidity.Daily recalibration is easy and it will even record data over time on a chart, though I don't think recorded data can be exported.My greatest criticism is establishing accuracy. You need another device to benchmark sensitivity; it most likely won't be accurate straight out of the box. Best if you have the opportunity to do this in open land away from urban development and early in the morning. It is still best to make comparison and adjust sensitivity of readings against other, trusted instrumentation. Once this has been done the device is a very handy tool indeed.