Provided is an aerosol collector of reduced size having an aerosol inlet, an impactor plate containing several particle size-selecting nozzles therethrough, a replaceable collection layer and a fan having a power supply such as a battery pack, all of which fits a small container, attachable to, e.g., the lapel of the user, means to rotate the fan and move the aerosol through the sampler, so as to draw airborne particles through the inlet and through one or more nozzles, to impact the particles on the layer for analysis of same.