Atmospheric Mercury Temporal Trends in the Northeastern United States from 1992 to 2014: Are Measured Concentrations Responding to Decreasing Regional Emissions?

• DOI: 10.1021/acs.estlett.6b00452
• Publication Date: 2016-12-27T19:28:16Z
• Authors: Hao Zhou; Chuanlong Zhou; Mary M. Lynam; J. Timothy Dvonch; James A. Barres; Philip K. Hopke; Mark Cohen; Thomas M. Holsen
• Keywords: Mercury; Elemental mercury

Long-term atmospheric mercury measurements at Underhill, VT (VT99), and Huntington Forest, NY (NY20), from 1992 to 2014 2005 2014, respectively, were used determine concentration trends using Mann–Kendall's tau test with Sen's slope estimator. These data, measured generally downwind of large Hg sources in the Midwestern United States, provide longest record ambient concentrations available States. At VT99, gaseous element (GEM), oxidized (GOM), particle-bound (PBM) declined rates −1.8, −3.2, −6.7%/year, respectively. NY20, GEM GOM −1.6 −7.8%/year, respectively; however, PBM increased a rate 2.0%/year, which is likely related winter wood burning. A trajectory ensemble analysis potential source contribution function indicates locations associated high changed Toronto–Buffalo Pennsylvania areas east coast urban centers. The declining northeastern States are positively correlated decreasing SO2 emissions upwind area. Overall, results indicate that decreased during past decade consistent regional point increasing global have not overwhelmed those decreases.