Global concentrations of gaseous elemental mercury and reactive gaseous mercury in the marine boundary layer

TY - JOUR

T1 - Global concentrations of gaseous elemental mercury and reactive gaseous mercury in the marine boundary layer

AU - Soerensen, A. L.

AU - Skov, H.

AU - Jacob, D. J.

AU - Sørensen, Britt Tang

AU - Johnson, Matthew Stanley

PY - 2010/10/1

Y1 - 2010/10/1

N2 - Gaseous elemental mercury (GEM) and reactive gaseous mercury (RGM) were measured during an eight month circumnavigation to obtain knowledge of their worldwide distributions in the marine boundary layer (MBL). Background GEM concentrations were found to be 1.32 ± 0.2 ng/m3 (summer) and 2.62 ± 0.4 ng/m3 (spring) in the northern hemisphere and 1.27 ± 0.2 ng/m3 (spring and summer) in the southern hemisphere. Radiation and relative humidity are shown to control diurnal cycles of RGM. During the cruise the ship passed areas of clean MBL air, air influenced by biomass burning (South Atlantic) and air with high concentrations of GEM and RGM of unknown origin (Antarctic). High GEM concentrations above the Atlantic indicate that emission from the ocean can be an important GEM source. Our data combined with data from earlier cruises provides adequate information to establish a seasonal cycle for the Atlantic. Results show a cycle similar to that found at Mace Head, Ireland but with larger amplitude. We have improved the basic knowledge of mean GEM and RGM concentrations in the MBL worldwide and shown how natural sources and reemissions can affect GEM concentrations in the MBL.

AB - Gaseous elemental mercury (GEM) and reactive gaseous mercury (RGM) were measured during an eight month circumnavigation to obtain knowledge of their worldwide distributions in the marine boundary layer (MBL). Background GEM concentrations were found to be 1.32 ± 0.2 ng/m3 (summer) and 2.62 ± 0.4 ng/m3 (spring) in the northern hemisphere and 1.27 ± 0.2 ng/m3 (spring and summer) in the southern hemisphere. Radiation and relative humidity are shown to control diurnal cycles of RGM. During the cruise the ship passed areas of clean MBL air, air influenced by biomass burning (South Atlantic) and air with high concentrations of GEM and RGM of unknown origin (Antarctic). High GEM concentrations above the Atlantic indicate that emission from the ocean can be an important GEM source. Our data combined with data from earlier cruises provides adequate information to establish a seasonal cycle for the Atlantic. Results show a cycle similar to that found at Mace Head, Ireland but with larger amplitude. We have improved the basic knowledge of mean GEM and RGM concentrations in the MBL worldwide and shown how natural sources and reemissions can affect GEM concentrations in the MBL.

M3 - Journal article

SN - 1086-931X

VL - 44

SP - 7425

EP - 7430

JO - Environmental Science & Technology. News & Research Notes

JF - Environmental Science & Technology. News & Research Notes

IS - 19

ER -