Meteorological and Chemical Behavior of Gaseous Sulfur Compounds in and around an Urban Valley

Sang-Keun Song,Zang-Ho Shon,Yoo-Keun Kim

doi:10.3319/tao.2010.04.28.01(a)

Abstract

The effects of photochemical oxidation of reduced sulfur compounds (RSCs: H2S, CH3SH, DMS, and DMDS) on SO2 production were evaluated at high (HV) and low ventilation (LV) conditions, based on a CALPUFF dispersion model coupled with photo-chemical oxidation mechanisms for four RSCs. The RSC emission concentrations used in the modeling were measured in and around an urban valley during a field campaign held in October 2008. SO2 production with LV (up to 156 ppb at 0900 LST) was found to be significantly higher than that with HV (up to 30 ppb). SO2 produced by photochemical oxidation of RSCs with LV (78% of total SO2 concentrations) was much higher than that with HV (27%), while the predominant RSC species were similar: DMDS (≥ 60% of the total contributions) with HV and LV when compared to three other RSCs (＜ 20%). The difference in SO2 concentration between HV and LV might be caused by the combined effects of photochemical oxidation of RSCs and ventilation condition.

Highlights

Air pollutants such as methane (CH4), reduced sulfur compounds (RSCs), and volatile organic compounds (VOCs) are known to constitute large portions of trace gas emissions in industrialized and/or polluted urban areas (Blaha et al 1999; Watts 2000; Ito et al 2001; Gurjar et al 2004; Kim 2006; Warneke et al 2007)
Since the early 2000s, Yangsan city has rapidly become urbanized and industrialized, causing a substantial increase in the concentration of odorous pollutants due to large point sources, geographical features, and meteorological conditions(Song et al 2009b). It includes a variety of source regions such as the industrial complexes (ICs) of Eogok (EG IC), Sanmak (SM IC), Yangsan (YS IC), and Bukjeong IC (BJ IC) located around an urban center area of Yangsan; Ungsang (US IC) and Ungbi IC (UB IC) located in the Ungsang area(Fig. 1)
The relatively low Index Of Agreement (IOA) of SO2 concentration might be due to the lack of information concerning RSCs and SO2 emission outside the industrial sources (S1 - S8) in the study area

Summary

Introduction

Air pollutants such as methane (CH4), reduced sulfur compounds (RSCs), and volatile organic compounds (VOCs) are known to constitute large portions of trace gas emissions in industrialized and/or polluted urban areas (Blaha et al 1999; Watts 2000; Ito et al 2001; Gurjar et al 2004; Kim 2006; Warneke et al 2007). Anthropogenic emissions of major RSCs such as hydrogen sulfide (H2S) and carbon disulfide (CS2) in polluted urban areas (3.3 and 0.34 Tg yr-1, respectively) were significantly (up to 8 times) higher than natural emissions [in wetlands/marshes (e.g., 0.7 and 0.1 Tg yr-1, respectively) and vegetation (e.g., 0.4 Tg yr-1)] (Watts 2000 and references therein). The anthropogenic emission rate of dimethyl sulfide (CH3SCH3, DMS)(0.13 Tg yr-1) was similar to emission rates in marshes (about 0.1) and wetlands (0.12), but significantly lower than emissions from vegetation (1.6)(Watts 2000). Many studies in recent decades have been concerned with assessing the emission characteristics of pollutant gases under diverse environmental settings (Loizidou and Kapetanios 1992; Davoli et al 2003; Muezzinoglu 2003; Kim 2006; Kim et al 2006)

Objectives

Methods

Results

Conclusion