Characterization of the Improved Experimental Setup for Multicomponent Aerosol Nucleation

ANDREY MARKOVICH (1), David Benson (1), Shan-Hu Lee (1)

(1) Kent State University

     Abstract Number: 626
     Last modified: May 14, 2010

Abstract
While remarkable advancement on atmospheric aerosol nucleation laboratory observations has been made recently, aerosol nucleation still remains as a controversial topic. For example, there are significant discrepancies amongst studies made by different groups and even between studies from the same groups. Attempts have also been made to reproduce atmospherically observed nucleation conditions in the laboratory, but these studies were usually made in not well-controlled experimental conditions and have lacked direct measurements of aerosol precursors.

In this presentation, we will present the characterization of our improved experimental setup used to study multicomponent nucleation involving sulfuric acid, ammonia, and organic compounds. We use a fast flow reactor which is temperature- and RH-controlled. Sulfuric acid is produced from the SO$_2 + OH reaction. Sulfuric acid, ammonia and organic compounds are measured directly by chemical ionization mass spectrometers. We will show how wall loss of sulphuric acid is determined experimentally and how the wall loss is minimized in the new flow reactor. Ammonia concentrations are measured, by taking into account the low concentrations of impurity ammonia originated from water (used to produce relative humidities). These improvements allow us to perform homogeneous nucleation experiments under the atmospherically relevant conditions to reproduce atmospheric observations from laboratory nucleation studies.