Charging: Please use any cell phone or other power adaptor that outputs at >=1000mA (the output is directly stated on the adaptor). Please avoid charging with a USB computer port which only output 500mA. It is recommended to fully charge for at least 2-3 hours before use for the longest battery life.PM measuring range: 0-999 ug/m3HCHO measuring Range: 0.001 – 1.999 mg/m3TVOC measuring range: 0.001 – 9.999 mg/mTemperature Range: -10˚C - 50˚C (14˚F - 122˚F) Storage Temperature: -10˚C - 60˚C (14˚F - 140˚F)Humidity Range: 20% - 85%