HIGHLY INTEGRATED OPTICAL PARTICLE COUNTER (OPC)

An apparatus and system for detecting and measuring particles entrained in an air stream. The apparatus and system include an enclosure configured to define an aerosol sampling path and an optical path. The aerosol sampling path allows an air stream having entrained particles to pass therethrough. The aerosol sampling path intersects with the optical path. The intersection defines a sensing region. The sensing region may use a band pass filter to improve signal to noise ratio. At least one flow rate sensor may be located near the sensing region. A light source provides a light beam along the optical path. The light beam intersects with the air stream in the sensing region, wherein the light beam may be scattered by entrained particles contained in the aerosol sampling path.