A tool to evaluate air quality model performances in regulatory applications

This paper describes the details of the DELTA Tool and Benchmarking service for air quality models,
recently developed in the framework of FAIRMODE (Forum for Air Quality Modelling in Europe). One of
the main objectives of the FAIRMODE activities is the development of a procedure for the evaluation and
benchmarking of air quality modelling applications for regulatory purposes. The DELTA Tool is a specific
software which provides summary statistics (i.e. BIAS, RMSE, correlation coefficient) as well as scatterplots,
time series plots, Taylor, Target and other diagrams providing an overview of the quality of
model results with respect to monitored data. Moreover, the benchmarking service implemented in
DELTA produces summary reports containing performance indicators related to a given model application
in the frame of the EU Air Quality Directive (AQD, 2008). This work describes the structure of the
DELTA tool and template for reporting model performances. Some examples of application are also
briefly presented.