Atmospheric gaseous mercury concentrations in New York State: relationships with meteorological data and other pollutants

Abstract

Abstract Ambient vapor-phase mercury concentrations including total gaseous mercury (TGM) and reactive gaseous mercury (RGM) were measured at three locations in rural New York State: Potsdam, Stockton, and Sterling. The RGM concentrations (4.2±6.4, 5.7±9.2, 6.0±10.8 pg m−3 at the Potsdam, Stockton, and Sterling sites, respectively) were about 0.2–3% of the total gaseous phase mercury concentration (TGM: 1.84±1.24, 1.83±1.32, 3.02±2.14 ng m−3, respectively) at the three monitoring sites. Standard deviations of RGM concentrations indicate that their daily variation was larger than that of TGM at all sites. This larger variation is probably because RGM is influenced by local sources to a greater extent than elemental mercury, which makes up to majority of TGM. There was no significant correlation between ozone and mercury concentrations. However, there was a significant positive correlation between water vapor mixing ratio and elemental mercury concentrations, suggesting that reduction of Hg2+ to Hg0 occurred in liquid water contained in clouds and fogs near the three monitoring sites. TGM concentrations had a generally negative correlation with ambient temperature, whereas RGM concentrations had a positive relationship. The negative relationship between TGM and temperature may be due to seasonal differences in emission rates of coal-fired power plants (winter maximum) in the northern hemisphere. This assumption was supported by a positive correlation between TGM and sulfur concentration, one of the major pollutants emitted from coal-fired power plants.