Source Apportionment

Results of the first European Source Apportionment intercomparison for Receptor and Chemical Transport Models

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In this study, the performance of the source apportionment model applications were evaluated by comparing the model results provided by 44 participants adopting a methodology based on performance indicators: z-scores and RMSE u , with pre-established acceptability criteria. Involving models based on completely different and independent input data, such as receptor models (RMs) and chemical transport models (CTMs), provided a unique opportunity to cross-validate them. In addition, comparing the modelled source chemical profiles, with those measured directly at the source contributed to corroborate the chemical profile of the tested model results. The most used RM was EPA- PMF5. RMs showed very good performance for the overall dataset (91% of z-scores accepted) and more difficulties are observed with SCE time series (72% of RMSE u accepted). Industry resulted the most problematic source for RMs due to the high variability among participants. Also the results obtained with CTMs were quite comparable to their ensemble reference using all models for the overall average (>92% of successful z-scores) while the comparability of the time series is more problematic (between 58% and 77% of the candidates’ RMSE u are accepted). In the CTM models a gap was observed between the sum of source contributions and the gravimetric PM 10 mass likely due to PM underestimation in the base case. Interestingly, when only the tagged species CTM results were used in the reference, the differences between the two CTM approaches (brute force and tagged species) were evident. In this case the percentage of candidates passing the z-score and RMSE u tests were only 50% and 86%, respectively. CTMs showed good comparability with RMs for the overall dataset (83% of the z-scores accepted), more differences were observed when dealing with the time series of the single source categories. In this case the share of successful RMSE u was in the range 25% - 34%.

New Intercomparison 2015-2016

This Intercomparison Exercise (IE) for Receptor and Source Oriented Models is organised within the framework of FAIRMODE Working Group 3 on Source Apportionment. The intercomparison has been designed to test both receptor oriented models (RMs) and source oriented models (CTMs). The target pollutant of this IE is PM10.

The main input data for RMs is a real world dataset while the input for CTMs includes: emission inventory, meteorological fields and boundary conditions.

For the intercomparison purposes, participants are requested to carry out the estimation of the source contributions using the desired methodology, report their results to the organisers and fill-in the questionnaire that will be distributed after the source apportionment results are delivered. The submission of participant’s results is expected by December 2015.

Results obtained with each of the two approaches will be evaluated separately. In addition, there will be a cross comparison between the two approaches for the area corresponding to the monitoring site were the real world dataset was collected.

The organisers will evaluate the results reported by participants using the methodology consolidated during the previous intercomparison exercises and present the IE results at the WG3 technical meeting. A draft report will be distributed to all participants for their comments.

After receiving all the comments, the final report/paper involving all participants will be published.

Those interested in the IE are kindly asked to send the application form as pdf by e-mail not later than August 31st to:


More detailed technical information will be distributed to the applicants.