Features Wide measurement range: Not only cigarette smoke, but also indoor dust, an asthma trigger, can be detected. Stable and sensitive measurements: Dual PWM output for particle sizes over 1 micron and 2.5 microns (approx.) Long-term use: Air is self-priming through the current of the air generating mechanism with built-in heater, easy to maintain Compact and light design: Compact size makes installation easier Easy to use: Compatible with Grove port, just plug-and-play Description The Particulate Matter level (PM level) in the air is measured by counting the Low Pulse Occupancy time (LPO time) in a given time unit. LPO time is proportional to PM concentration. This sensor can provide reliable data for air purifier systems; it is responsive to PM of diameter 1μm.