Determination of the number size distribution of submicron atmospheric aerosols using a differential mobility particle sizer

Abstract

Ultra-fine aerosol particles may contain excessive amounts of harmful substances that can be easily inhaled and eventually enter into the human blood stream. The objective of this study was to determine the number size distribution of aerosol particles in the size range of 0.01 - 0.8μm, and to investigate the existence of new particle formation and growth events in the Botsalano Game Reseve, which is a typical savannah environment. The average daily particle number concentration ranged from 7 40 cm-3 to 10000 cm-3 and the particle growth was observed mainly within the range of 10 to 100nm. Seasonal variations in the total particle number concentrations were observed with high values in summer and low values in winter. It has also been observed that particle formation and growth events can be observed mainly during the day. The differential mobility particle sizer proved to be a relevant tool for determination of particle size distribution.