In situ measurements of speciated atmospheric mercury and the identification of source regions in the Mexico City Metropolitan Area A. P. Rutter1, D. C. Snyder1, E. A. Stone1, J. J. Schauer1,2, R. Gonzalez-Abraham3, L. T. Molina3,4, C. Márquez5, B. Cárdenas5, and B. de Foy3,6 1Environmental Chemistry and Technology Program, Univ. of Wisconsin, 660 N. Park Street, Madison, WI 53706, USA 2Wisconsin State Laboratory of Hygiene, Univ. of Wisconsin, 2601 Agriculture Drive, Madison, WI 53718, USA 3Molina Center for Energy and the Environment 2, 3262 Holiday Ct. Suite 201, La Jolla, CA 92037, USA 4Massachusetts Institute of Technology, Cambridge, MA 02319, USA 5Centro Nacional de Investigación y Capacitación Ambiental CENICA, Instituto Nacional de Ecología-SEMARNAT., Periférico 5000, Mexico City, 04530, Mexico 6Department of Earth and Atmospheric Sciences, Saint Louis University, 3642 Lindell Blvd., St. Louis, MO 63108, USA
Abstract. In order to expand the currently limited understanding of atmospheric
mercury source-receptor relationships in the Mexico City Metropolitan Area,
real time measurements of atmospheric mercury were made at a downtown urban
site, and a rural site on the outskirts of Mexico City, during March 2006.
Numerous short-lived increases in particulate mercury (PHg) and reactive
gaseous mercury (RGM) concentrations were observed at the urban site during
the 17 day study, and less frequent increases in gaseous elemental mercury
(GEM) concentrations were measured at both the urban and rural sites. The
episodic increases observed were attributed to plume impacts from industrial
point source emissions in and around Mexico City. Average concentrations and
standard deviations measured during the study were as follows: i) urban
site; PHg=187±300 pg m−3, RGM=62±64 pg m−3, GEM=7.2±4.8 ng m−3,
and; ii) rural site; GEM=5.0±2.8 ng m−3.
Several source regions of atmospheric mercury to the urban and rural sites
were determined using Concentration Field Analysis, in which atmospheric
mercury measurements were combined with back trajectory data to
determine source regions. Only some source regions correlated to mercury emission
sources listed in the Federal Pollutant Release and Transfer Register,
leaving the rest unaccounted for. Contributions of anthropogenic mercury
point sources in and around Mexico City to concentration averages measured
at the urban site during the study were estimated to be: 93±3% of
reactive mercury (PHg and RGM), and; 81±0.4% of GEM. Point source
contributions to GEM measured at the rural site were 72±1%. GEM
and reactive mercury (PHg+RGM) were not found to correlate with biomass
burning at either of the measurement sites.
Citation: Rutter, A. P., Snyder, D. C., Stone, E. A., Schauer, J. J., Gonzalez-Abraham, R., Molina, L. T., Márquez, C., Cárdenas, B., and de Foy, B.: In situ measurements of speciated atmospheric mercury and the identification of source regions in the Mexico City Metropolitan Area, Atmos. Chem. Phys., 9, 207-220, doi:10.5194/acp-9-207-2009, 2009.