Evaluation of particle growth systems for sampling and analysis of atmospheric fine particles

Abstract

Three types of water-based condensational growth systems, which can enable particles to grow in size to facilitate sampling and subsequent chemical analysis, were evaluated. The first one is a mixing type growth system where aerosols are mixed with saturated water vapor, the second one is a thermal diffusive growth system where warm flow enters cold-walled tube, and the third one is a laminar flow type where cold flow enters a warm wet-wall tube. Hygroscopic sodium chloride (NaCl), ammonium sulfate ((NH(4))(2)SO(4)) and ammonium nitrate (NH(4)NO(3)), and non-hygroscopic polystyrene latex (PSL) particles, in the size range of 50-400 nm, were used to determine their growth factors through the growth systems. Our data showed that the third-type growth system could enable particles to grow most efficiently regardless of their hygroscopic property. Collection efficiency of particles in the size range of 0.05-2.5 mu m, in a continuous aerosol sampler after they passed through the third-type growth system was about 100%, suggesting that the third-type growth system would be the most useful among the tested growth systems for sampling and subsequent chemical analysis of fine and ultrafine particles. (C) 2011 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.