KCO Particle Number Concentration Intercomparison

Optical Particle Counters

University of Alaska / University of California, Riverside

Sergio A. Guazzotti, Keith R. Coffee and Kimberly A. Prather (UCR)
Will Cantrel and Glenn Shaw (UA)

Reported particle number concentrations from University of Alaska were obtained with the OPC (CLIMET) sampling from the University of Miami inlet. Reported particle number concentrations from University of California, Riverside were obtained at ambient relative humidity.

As it can be seen in the figures, the OPC from the University of California, Riverside (Particle Measuring Systems, Inc.) undercounted particles with d >0.5 mm before being fixed on site at noon on February 22, 1999. After that day, there is good agreement between the two instruments.

For particles with diameter between 0.3 and 0.5 mm, the OPC from University of Alaska showed lower values for particle concentrations during all the days used for the intercomparison.

Further tests will be carry out to evaluate the reason for the reported lower particle number concentrations in the lowest size bin form the University of Alaska’s OPC when compared with the OPC from UCR and the SMPS form UAF.