Characterization of Atmospheric Dry Deposition of Polychlorinated Dibenzo-p-dioxins/Dibenzofuran in a Rural Area of Taiwan

Chun-Jen Huang,Kang-Shin Chen,Lin-Chi Wang,Guo-Ping Chang-Chien,Yi-Chieh Lai

doi:10.4209/aaqr.2011.03.0033

Abstract

The characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and the variation of the gas-particle partitioning of PCDD/Fs near two municipal solid waste incinerators (MSWIs) located in southern Taiwan were investigated. In order to better understand the mechanism of dry deposition, the atmospheric dry deposition flux and velocity of PCDD/Fs were calculated. It was found that the mean atmospheric PCDD/F concentrations (0.0386-0.106 pg I-TEQ/Nm^3) were comparable to those detected in the vicinity of MSWIs in Taiwan, but significantly lower than those in a highly industrialized urban area (0.15 pg I-TEQ/Nm^3) located in southern Taiwan. The relatively higher atmospheric PCDD/F concentrations was found in winter than in summer, probably because of several loss process including photolysis, chemical reactivity, wet and dry deposition, and scavenging by vegetation. The calculated total dry deposition flux of PCDD/Fs ranged from 0.0274-0.718 ng I-TEQ/m^2-month, and the atmospheric deposition flux in winter tended to be higher than those in summer. The results also indicated that dry deposition velocities of atmospheric particles for each month ranged from 0.52-0.91 cm/s (mean=0.63 cm/s) and 0.48-0.73 cm/s (mean=0.55 cm/s) in sites A and B, respectively, which were similar to that for the ambient air near two MSWIs in Taiwan, but slightly higher than those in urban area of Korea. In addition, the dry deposition of PCDD/Fs was mainly contributed by particle-phase at both sampling areas during the estimated period. The above results demonstrated that the dominant mechanism of dry deposition was particle phase deposition.

Highlights

INTRODUCTIONPBDD/Fs and exited in both gas and particle phases in the ambient air and in the stack flue gases (Lee et al, 1996; Lai et al, 2007; Chen et al, 2011)
Polychlorinated dibenzo-p-dioxins and dibenzofurans have received much public concern over the last decade due to their potential adverse health effects, such as reproductive difficulties and increased risk of cancer
The results indicated that dry deposition velocities of atmospheric particles for each month ranged from 0.52–0.91 cm/s and 0.48–0.73 cm/s in sites A and B, respectively, which were similar to that for the ambient air near two municipal solid waste incinerators (MSWIs) in Taiwan, but slightly higher than those in urban area of Korea

Summary

INTRODUCTION

PBDD/Fs and exited in both gas and particle phases in the ambient air and in the stack flue gases (Lee et al, 1996; Lai et al, 2007; Chen et al, 2011). Dry deposition depends significantly on the gas-particle distribution of PCDD/Fs (Oh et al, 2001). Shih et al (2006) reported the atmospheric dry deposition flux of total PCDD/Fs in rural area averaged 150 pg/m2/day, and the calculated dry deposition velocity of total PCDD/Fs was 0.42 cm/s. The mean dry deposition fluxes of total PCDD/Fs ranged from 9.81–29.1 pg I-TEQ/m2-day for the four investigated sites (a commercial suburban area, an industrial area, a coastal area, and an agricultural rural area), while those of wet deposition ranged from 19.2–47.8 pg I-TEQ/L (Wang et al, 2010). In order to clarify the important features, this study investigates the atmospheric PCDD/F concentration and the variation of the gas-particle partitioning of PCDD/Fs in the vicinity of two municipal solid waste incinerators (MSWIs) located in a rural area of Taiwan. Estimated monthly dry deposition velocities of PCDD/Fs were calculated by using the PCDD/F concentrations and dry deposition fluxes data

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS