TY - JOUR
T1 - Temporal distribution and potential sources of atmospheric mercury measured at a high-elevation background station in Taiwan
AU - Sheu, Guey Rong
AU - Lin, Neng Huei
AU - Wang, Jia Lin
AU - Lee, Chung Te
AU - Ou Yang, Chang Feng
AU - Wang, Sheng Hsiang
N1 - Funding Information:
We thank Dr. Matthew Landis for providing helpful advice on operating the Hg speciation system at high elevation. We also thank two anonymous reviewers for their thoughtful and constructive comments on the manuscript. This study is financially supported by the Taiwan Environmental Protection Administration under contracts No. EPA-96-U1L1-02-101 and EPA-97-U1L1-02-101 , and by National Science Council under contracts No. NSC 95-2752-M-008-007-PAE and NSC 96-2752-M-008-007-PAE . Part of the research manpower and laboratory facilities was funded by National Central University .
PY - 2010/6
Y1 - 2010/6
N2 - Measurements of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and particulate mercury (PHg) have been conducted at Lulin Atmospheric Background Station (LABS) in Taiwan since April 2006. This was the first long-term free tropospheric atmospheric Hg monitoring program in the downwind region of East Asia, which is a major Hg emission source region. Between April 13, 2006 and December 31, 2007, the mean concentrations of GEM, RGM, and PHg were 1.73 ng m-3, 12.1 pg m-3, and 2.3 pg m-3, respectively. A diurnal pattern was observed for GEM with afternoon peaks and nighttime lows, whereas the diurnal pattern of RGM was opposite to that of GEM. Spikes of RGM were frequently observed between midnight and early morning with concurrent decreases in GEM and relative humidity and increases in O3, suggesting the oxidation of GEM and formation of RGM in free troposphere (FT). Upslope movement of boundary layer (BL) air in daytime and subsidence of FT air at night resulted in these diurnal patterns. Considering only the nighttime data, which were more representative of FT air, the composite monthly mean GEM concentrations ranged between 1.06 and 2.06 ng m-3. Seasonal variation in nighttime GEM was evident, with lower concentrations usually occurring in summer when clean marine air masses prevailed. Between fall and spring, air masses passed the East Asian continent prior to reaching LABS, contributing to the elevated GEM concentrations. Analysis of GEM/CO correlation tends to support the argument. Good GEM/CO correlations were observed in fall, winter, and spring, suggesting influence of anthropogenic emission sources. Our results demonstrate the significance of East Asian Hg emissions, including both anthropogenic and biomass burning emissions, and their long-range transport in the FT. Because of the pronounced seasonal monsoon activity and the seasonal variation in regional wind field, export of the Asian Hg emissions to Taiwan occurs mainly during fall, winter, and spring.
AB - Measurements of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and particulate mercury (PHg) have been conducted at Lulin Atmospheric Background Station (LABS) in Taiwan since April 2006. This was the first long-term free tropospheric atmospheric Hg monitoring program in the downwind region of East Asia, which is a major Hg emission source region. Between April 13, 2006 and December 31, 2007, the mean concentrations of GEM, RGM, and PHg were 1.73 ng m-3, 12.1 pg m-3, and 2.3 pg m-3, respectively. A diurnal pattern was observed for GEM with afternoon peaks and nighttime lows, whereas the diurnal pattern of RGM was opposite to that of GEM. Spikes of RGM were frequently observed between midnight and early morning with concurrent decreases in GEM and relative humidity and increases in O3, suggesting the oxidation of GEM and formation of RGM in free troposphere (FT). Upslope movement of boundary layer (BL) air in daytime and subsidence of FT air at night resulted in these diurnal patterns. Considering only the nighttime data, which were more representative of FT air, the composite monthly mean GEM concentrations ranged between 1.06 and 2.06 ng m-3. Seasonal variation in nighttime GEM was evident, with lower concentrations usually occurring in summer when clean marine air masses prevailed. Between fall and spring, air masses passed the East Asian continent prior to reaching LABS, contributing to the elevated GEM concentrations. Analysis of GEM/CO correlation tends to support the argument. Good GEM/CO correlations were observed in fall, winter, and spring, suggesting influence of anthropogenic emission sources. Our results demonstrate the significance of East Asian Hg emissions, including both anthropogenic and biomass burning emissions, and their long-range transport in the FT. Because of the pronounced seasonal monsoon activity and the seasonal variation in regional wind field, export of the Asian Hg emissions to Taiwan occurs mainly during fall, winter, and spring.
KW - Biomass burning
KW - Gaseous elemental mercury
KW - Long-range transport
KW - Particulate mercury
KW - Reactive gaseous mercury
UR - http://www.scopus.com/inward/record.url?scp=77953620398&partnerID=8YFLogxK
U2 - 10.1016/j.atmosenv.2010.04.009
DO - 10.1016/j.atmosenv.2010.04.009
M3 - 期刊論文
AN - SCOPUS:77953620398
SN - 1352-2310
VL - 44
SP - 2393
EP - 2400
JO - Atmospheric Environment
JF - Atmospheric Environment
IS - 20
ER -
