Airborne mercury species at the Råö background monitoring site in Sweden: Distribution of mercury as an effect of long range transport
Abstract. Within the EU project, Global Mercury Observation System (GMOS) airborne mercury have been monitored at the background Råö measurement site on the west coast of Sweden from mid May 2012 tot the beginning of July 2013 and from the beginning of February 2014 to the end of May 2015. The mercury concentrations measured at the Råö site was found to be low in comparison to other comparable European measurement sites. A back trajectory analysis to study the origin of air masses reaching the Råö site was performed. Due to the remotely location of the Råö measurement station it receives background air most of the time. However, elevated concentrations with air masses coming from especially the south east are noticeable. Evidence for formation of gaseous oxidised mercury (GOM) in background free tropospheric air is presented.