An integrated particle detection apparatus for optical detection of particles in an air stream. The particle detection apparatus includes a scalper for removing large panicles from the air stream, a concentrator for separating out small particles and increasing the concentration of particles of interest, and a fluorescence sensor system for detecting the particles present in the air stream. The scalper, concentrator and sensor comprise a single integrated unit, such that the scalper is fluidly contiguous with the concentrator and the concentrator is fluidly contiguous with the sensor.