Intercomparison between three receptor-oriented models applied to acidic species in precipitation

Three different receptor-oriented models have been tested on the precipitation chemical data of a background station in France from 1992 to 1995. These models which allowed the identification of source–receptor relationships for acidic species (non-sea salt SO42−, NO3− and NH4+) in rain have been compared. The receptor-oriented methodologies are based on the same construction scheme. Precipitation data and air parcel backward trajectories were combined in the model calculations to produce probability or concentration maps of likely contributing sources. The regions of Europe identified by the three models generally coincide well with the location of known emission sources. Using non-parametric Spearman rank-order correlation, the computed concentrations provided by these three models were compared with the European emissions established by EMEP. A good correlation was found between computed ionic concentrations and the emissions of SO2, NOx and NH3. Each model shows its own advantages to examine the source regions that give high concentrations of acidic species at a receptor site.