Measurement and mitigation of response discontinuities of a widely used condensation particle counter

Comparison of particle number concentration measurements recorded using condensation particle counters (CPCs) is an essential data interpretation tool in the analysis (and assurance of comparability) of spatial and temporal variations recorded by networks of instruments. In this paper, the relative performance of two TSI 3022A CPCs is compared using field and laboratory measurements. Good correlation is seen between the two instruments over most of the measurement range tested, but a significant discontinuity of around 20% is found upon switching between different measurement modes. The impact of this discontinuity on measurements spanning the switch between measurement modes is discussed and potential methods of mitigation suggested.