Fast Time Resolution Oxidized Mercury Measurements
during the Reno Atmospheric Mercury Intercomparison Experiment (RAMIX)
- Publication date
- Publisher
Abstract
The
Reno Atmospheric Mercury Intercomparison Experiment (RAMIX)
was carried out from 22 August to 16 September, 2011 in Reno, NV to
evaluate the performance of new and existing methods to measure atmospheric
mercury (Hg). Measurements were made using a common sampling manifold
to which controlled concentrations of Hg species, including gaseous
elemental mercury (GEM) and HgBr<sub>2</sub> (a surrogate gaseous
oxidized mercury (GOM) compound), and potential interferents were
added. We present an analysis of Hg measurements made using the University
of Washington’s Detector for Oxidized Hg Species (DOHGS), focusing
on tests of GEM and HgBr<sub>2</sub> spike recovery, the potential
for interference from ozone (O<sub>3</sub>) and water vapor (WV),
and temporal variability of ambient reactive mercury (RM). The mean
GEM and HgBr<sub>2</sub> spike recoveries measured with the DOHGS
were 95% and 66%, respectively. The DOHGS responded linearly to HgBr<sub>2</sub>. We found no evidence that elevated O<sub>3</sub> interfered
in the DOHGS RM measurements. A reduction in RM collection and retention
efficiencies at very high ambient WV mixing ratios is possible. Comparisons
between the DOHGS and participating Hg instruments demonstrate good
agreement for GEM and large discrepancies for RM. The results suggest
that existing GOM measurements are biased low