Atmospheric Mercury (Hg) Concentrations in New York: A Comparison between Urban and Rural Areas
Hyun-Deok Choi*, Jiaoyan Huang and Thomas M. Holsen
Department of Civil and Environmental Engineering
8 Clarkson Ave.
Potsdam, NY 13699-5710, USA
Speciated atmospheric Hg concentrations are being measured using two Tekran mercury speciation systems in Rochester (urban) and Huntington Forest (HF) (rural) in New York state. Since 2007, the average concentrations ± standard deviation (S.D.) (range) of GEM, RGM, and PBM at the Rochester site were 1.6 ± 0.4 (0.9 to 16.4) ng m-3, 5.3 ± 10.7 (< detection limit (DL) to 178) pg m-3, and 11.0 ± 14.7 (< DL to 204) pg m-3, respectively. The average concentrations ± S.D. (range) of GEM, RGM, and PBM at the HF site were 1.4 ± 0.3 (0.5 to 3.0) ng m-3, 1.1 ± 2.7 (< DL to 86.7) pg m-3, and 3.7 ± 7.5 (< DL to 297) pg m-3, respectively. The seasonal mean concentrations of GEM were highest in winter at both sites although the GEM concentrations at the Rochester site were more constant than at the HF site. The mean concentration of RGM was highest and most variable in spring at Rochester whereas the RGM concentration was highest and most variable in winter season at HF. The PBM concentrations were highest and most variable in winter at both the Rochester and HFt sites. Diurnal variations in RGM concentrations with a maximum during the daytime and minimum during nighttime were observed at both sites. However, during warm seasons regular patterns of maximum GEM in the mid afternoon and minimum GEM at night were observed at the HF site while maximum GEM during the night and minimum GEM in the mid afternoon were observed at Rochester. Diurnal variations of PBM were not clearly observed at either site. For 12 high concentration events, GEM and CO concentrations were positively correlated (r2>0.54-0.84; p<0.001) for the Rochester site for periods between three to eight days. During the events RGM and SO2 were also positively correlated (r2=0.39-0.76; p<0.001) except two events (r2=0.14; p<0.001 and r2=0.02; p<0.001). Overall ozone concentrations were positively correlated with RGM concentrations at both the Rochester and HF sites (rs=0.342, p<0.001; rs=0.325, p<0.001, respectively). Hybrid receptor modeling suggests sources of GEM, RGM and PBM were different but consistent with current emissions inventories.
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