Abstract: A method for analyzing particles in an air stream includes concentrating the particles in an interior region of the air stream and deflecting the concentrated particles in the air stream with a generated thermal gradient. Smaller particles in the air stream may be selectively deflected away from the interior region and towards a periphery of the air stream at a different rate than larger particles in the air stream. The generated thermal gradient may be controlled to deflect particles in a selected particle size range onto a surface of a particle detector. An effective mass of the collected particles and an aerosol mass concentration estimate of the particles within the selected particle size range may be generated. Systems for analyzing particles are also disclosed.