GP2Y1010AU0F is a dust sensor by optical sensing system. An infrared emitting diode (IRED) and an phototransistor are diagonally arranged into this device. It detects the reflected light of dust in air. Especially, it is effective to detect very fine particle like the cigarette smoke. In addition it can distinguish smoke from house dust by pulse pattern of output voltage.

Specification:

Compact, thin package (46.0 × 30.0 × 17.6 mm)
Low consumption current (Icc: MAX. 20 mA)
The presence of dust can be detected by the photometry of only one pulse
Enable to distinguish smoke from house dust
Lead-free and RoHS directive compliant


Link:
http://arduinodev.woofex.net/2012/12/01/standalone-sharp-dust-sensor/