The dynamical impact of Rossby wave breaking upon UK PM.sub.10 concentration

Coarse particulate matter (PM.sub.10) has long been understood to be hazardous to human health, with mortality rates increasing as a result of raised ground level concentrations. We explore the influence of synoptic-scale meteorology on daily mean observed PM.sub.10 concentration ([PM.sub.10 ]) using Rossby wave breaking (RWB). Meteorological reanalysis data for the winter months (DJF) between January 1999 and December 2008 and observed PM.sub.10 data for three urban background UK (Midland) sites were analysed. Three RWB diagnostics were used to identify RWB that had significant influence on UK Midland PM.sub.10 . RWB events were classified according to whether the RWB was cyclonic or anticyclonic in its direction of breaking and whether the RWB event was influenced more by poleward or equatorial air masses. We find that there is a strong link between RWB events and UK [PM.sub.10 ]. Significant increases (p