The hypothesis of this thesis is that the time-of-flight method of determining an
estimate of the aerodynamic diameter of aerosol particles is fundamentally flawed
when applied to non-spherical and/or non-unit density particles. Such a
particle-sizing system, the TSI Aerodynamic Particle Sizer, is challenged with solid,
non-spherical particles of known aerodynamic diameter to assess the influence of
particle shape on instrument response. The aerodynamic diameter of the
non-spherical particles is also determined under gravitational settling. Deposits that
had been size-separated are resuspended for aerodynamic sizing by the APS. The
experimental study is supplemented by a theoretical investigation of the relative
effects of particle density and shape on APS-measured diameters. This is achieved
through the development of a computational routine to calculate the trajectories of
particles of various densities and shapes through the APS nozzle and sensing zone.
The results of these calculations are compared with the experimentally-measured APS
performance. The consequences for the traceability and accuracy of data measured
using this technique are assessed in the light of the outcome of both aspects of the
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.