Urban–rural differences in atmospheric mercury speciation |
| |
| Authors: | Bian Liu Gerald J Keeler J Timothy Dvonch James A Barres Mary M Lynam Frank J Marsik Joy Taylor Morgan |
| |
| Institution: | 1. University of California—Santa Cruz, USA;2. National Atmospheric Deposition Program, University of Illinois — Urbana Champaign, USA;3. U.S. Geological Survey, Mounds View, MN, USA;4. Meteorological Service of Canada, Environment Canada, Edmonton, Alberta, Canada;5. University of Nevada, Reno, USA;6. Electric Power Research Institute, Palo Alto, CA, USA;1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China;2. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong;3. Open Research Station of Changbai Mountain Forest Ecosystems, Institute of Applied Ecology, Chinese Academy of Sciences, Yanbian 133613, China;4. Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Ontario, Canada |
| |
| Abstract: | Measurements of gaseous elemental mercury (GEM), particulate mercury (Hgp), and reactive gaseous mercury (RGM) were concurrently recorded at an urban site in Detroit and a rural site in Dexter, both in Michigan for the calendar year 2004. Their average concentrations (±standard deviation) for the urban area were 2.5 ± 1.4 ng m?3, 18.1 ± 61.0 pg m?3, and 15.5 ± 54.9 pg m?3, respectively, while their rural counterparts were 1.6 ± 0.6 ng m?3, 6.1 ± 5.5 pg m?3, and 3.8 ± 6.6 pg m?3, respectively. The medians of urban-to-rural ratios of Hg concentrations indicate approximately 1-fold, 2-fold, and 3-fold gradients between Detroit and Dexter for GEM, Hgp, and RGM, respectively. The urban–rural differences in Hg also varied considerably on different temporal scales and with wind flow patterns, which was most evident in RGM. Our results show that while Hg at both sites was impacted by regional sources, meteorological conditions, and photochemical transformations, the extent of variations in the observed urban-to-rural gradients, particularly in RGM, cannot be fully accounted for by these processes. Both analyses of the annual data and case studies indicate that the more variable and episodic nature of Hg, particularly RGM, seen in Detroit compared with Dexter, was the result of direct impact from local anthropogenic sources. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
