Pathogen and particle detector system and method

A method of detecting pathogens and particles, the method comprising the steps of:

• emitting a beam of light;
• transmitting at least a portion of the beam of light through a first wavelength selective device;
• impinging a sampling area containing particles with a portion of the beam of light, wherein the particles scatter the light in a forward direction and in a backward direction;
• receiving at least a portion of the forward scattered light with a first optical detector, whereby particles are sized on the basis of the forward scattered light;
• and
• receiving at least a portion of the backward scattered light at a second optical detector whereby fluorescence from the particles that scattered the light in the backward direction is detected and the particles are determined to be biologic or non-biologic on the basis of said fluorescence.

A particle detector system, comprising:

• a sampling area;
• a light source on one side of the sampling area for sending a substantially collimated beam of light through the sampling area, whereby portions of the beam of light are scattered at various angles by particles of various sizes present in the sample area, and an unscattered portion of the beam of light remains unscattered;
• a beam blocking device on an opposite side of the sampling area for blocking at least the portion of the unscattered portion of the beam of light and for limiting a range of particles measured;
• a first optical detector positioned in the light path after the beam blocking device for detecting a portion of forward scattered light, and producing an output including information on a number of forward scattered particles in the light path within a predetermined size range;
• a second optical detector on the light source side of the sampling area for detecting a portion of backward scattered light, and producing an output including information on the fluorescence of and a number of backward scattered particles in the light path within a predetermined size range;
• and
• a first optic element to transmit only a specific waveband of the portion of the forward scattered light toward the first optical detector, wherein other wavebands are reflected by the filter along an optic path toward the second optical detector.