Environmental Engineering Reference
In-Depth Information
4.2 Measurement of Water-Soluble Organic Acids
in Gaseous and Particulate Phases at a Suburban Site
in Saitama, Japan
Linfa Bao and Kazuhiko Sakamoto
Department of Environmental Science and Technology, Graduate School of Science and
Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan
Abstract
In summer, daily variation of water-soluble organic acids showed that
gaseous and particulate phase concentrations reached the maximum in the daytime,
and got down at deep night. The average abundances in gaseous phase to the total
of organic acids ([G]/[P + G]) were 36%. The formation mechanism according to
physical interactions was evaluated using a gas-particle sorption equilibrium model. It
is suggested that the gas-to-particle sorption has occurred, but the sorption equilibrium
has not reached yet. Gas-particle partitioning of organic acid depends not only on
physical and chemical characteristics of organic acids, but also on other chemical
compositions in aerosols.
Keywords
Gas-particle partitioning, dicarboxylic acids, ketocarboxylic acids,
oxygenated organic aerosol (OOA)
1. Introduction
Water-soluble dicarboxylic acids may affect aerosol's hygroscopic and cloud-
nucleating properties (Peng et al., 2001; Abbatt et al., 2005), but the details of their
secondary formation mechanisms and behaviors are still unclear. Dicarboxylic
acids were considered to be principally associated with particle phase due to their
relatively low vapour pressures and their hygroscopic behavior. However, recent
investigations have shown that dicarboxylic acids display a semi-volatile behavior
(Limbeck et al., 2001). A suitable approach for the correction of these semi-volatile
compounds is the use of a denuder-filter-adsorbent system for sample collection
(Limbeck et al., 2005). In this study, water-soluble organic acids (mainly dicarboxylic
acids) in gaseous and particulate phases at a suburban site were investigated with
an annular denuder-filter pack system.
