Systems and methods for use in detecting harmful aerosol particles

1. In an environment having fluid containing a plurality of particles, wherein the fluid flows in a direction such that particles within the fluid pass through a region of space, a particle detection method, comprising:

using an emitter to emit excitation energy into the region while the fluid is flowing though the region so that a particle in the fluid is illuminated by the excitation energy, whereby, in response to the exposure of the particle to the excitation energy, elastic and/or inelastic emissions are produced;

separating the elastic and/or inelastic emissions into two or more emission spectral regions;

separately directing the spectral region-separated emissions into optical fibers or energy waveguides, with the fibers or waveguides of sufficiently different lengths such that the spectral region-separated output of each fiber or waveguide arrives at a single detector at distinct times such that each spectral region-separated emission can be separately measured at the output of the detector;

using a second emitter to emit second excitation energy into a second region while the fluid is flowing through the second region so that a particle in the fluid is illuminated by the second excitation energy, whereby, in response to the exposure of the particle to the second excitation energy, second elastic and/or inelastic emissions are produced;

using a second detector positioned to receive the second elastic or inelastic emissions from the particle; and

in response to the second detector receiving at least a predetermined amount of emissions from the particle, generating a signal, wherein the signal is configured to cause the first emitter to output an excitation pulse such that the particle is illuminated by the excitation pulse.

2. The method of claim 1 , in which the second emitter is a laser or LED operated in a continuous mode.

3. The method of claim 1 , comprising using a dichroic filter, a series of dichroic filters, a dispersion grating, and/or a dispersion prism to separate the elastic and inelastic emissions into two or more emission spectral regions.

4. The method of claim 1 , in which, in response to the exposure of the particle to the excitation energy, elastic scattering and fluorescence are produced.

5. The method of claim 1 , in which, in response to the exposure of the particle to the excitation energy, two or more spectral regions of fluorescence are produced.

6. The method of claim 1 , in which the emitter is a laser or LED operated in a pulsed mode.

7. The method of claim 1 , in which the elastic and inelastic emissions, or inelastic emissions signals are compared to known particle characteristics to differentiate at least one type of particle from another type of particle.

8. The method of claim 7 , in which biological particles are differentiated from other types of particles.