A new particle mass classifier, the Couette centrifugal particle mass analyzer (CPMA), is
described and compared to the existing aerosol particle mass (APM) analyzer. The Couette
CPMA and APM use centrifugal and electrostatic forces to classify particles according to
their mass-to-charge ratio. The APM consists of two rotating coaxial electrodes, rotating at
the same angular velocity, between which charged particles pass. Depending on the voltage
and rotational speeds of the electrodes, particles of different mass-to-charge ratios will be …