Improvements to the Regional Deterministic Air Quality Analysis System for Ozone and PM2.5 at the Surface at the Canadian Meteorological Center

In February 2013, in collaboration with the Air Quality Research Division, the Canadian Meteorological Centre (CMC) implemented into operations a new surface analysis for air quality species (ozone and PM2.5). The Regional Deterministic Air Quality Analysis (RDAQA) generates analyses every hour using the operational GEM-MACH Regional Air Quality Deterministic Prediction System (48 h forecasts on a domain with 10-km horizontal grid spacing and 80-vertical levels) to provide the trial fields. Surface observations are from Canadian regional data providers and the US EPA/AIRNow Program. An optimal interpolation scheme adapted to air quality is used to blend model and observations. A verification of the RDAQA shows major reductions in the error variance and bias of the analysis with respect to the model forecasts as compared to observations.