To test the new BROWSE-PEARL model an Italian example scenario has been developed. Hourly weather data have been obtained from a weather station near Bologna in Emilia Romagna Region in Italy. Vines were chosen as a representative crop for Italy and crop parameters for testing the BROWSE-PEARL model were taken from FOCUS Piacenza scenario. To test the new BROWSE-PEARL model an Italian example scenario has been developed. Hourly weather data have been obtained from a weather station near Bologna in Emilia Romagna Region in Italy. Vines were chosen as a representative crop for Italy and crop parameters for testing the BROWSE-PEARL model were taken from FOCUS Piacenza scenario ACKNOWLEDGMENTS The output of multiple runs using the coupled BROWSE-PEARL/OPS models will be used in the software tools developed in the BROWSE project for regulators to evaluate the exposure of operators, workers, bystanders and residents after volatilisation of PPPs from treated areas. For the processes competing with volatilisation from plants (photo- transformation, penetration into the plant leaves, wash-off by rainfall), different layers in the plant canopy will be considered in order to deal with different pesticide deposition in each layer. In order to determine vapour concentrations at appropriate locations within a landscape, there is a requirement to couple an emission model such as BROWSE-Pearl to a dispersion model. For this reason BROWSE-Pearl will be coupled to the atmospheric dispersion model OPS (Van Jaarsveld, 2004). OPS (Operational atmospheric transport model of Priority Substances) is a model that simulates the atmospheric process sequence of emission, dispersion, transport, chemical conversion and finally deposition. In order to determine vapour concentrations at appropriate locations within a landscape, there is a requirement to couple an emission model such as BROWSE-Pearl to a dispersion model. For this reason BROWSE-Pearl will be coupled to the atmospheric dispersion model OPS (Van Jaarsveld, 2004). OPS (Operational atmospheric transport model of Priority Substances) is a model that simulates the atmospheric process sequence of emission, dispersion, transport, chemical conversion and finally deposition. The volatilisation of pesticides from plant surfaces can also be described using the concept of transport resistances (van den Berg and Leistra, 2004). As these resistances depend on the prevailing meteorological conditions, hourly meteorological data are needed as input for PEARL. 1 FOCUS (2008). “Pesticides in Air: Considerations for Exposure Assessment”. Report of the FOCUS Working Group on Pesticides in Air (authors: R. Kubiak, L. Bürkle, I. Cousins, A. Hourdakis, T. Jarvis, B. Jene, W. Koch, J. Kreuger, W-M. Maier, M. Millet, W. Reinert, P. Sweeney, J-C. Tournayre, F. Van den Berg), EC Document Reference SANCO/10553/2006 Rev 2 (June 2008). Leistra, M.,Van der Linden, A.M.A., Boesten, J.J.T.I., and Van den Berg, F. (2001). PEARL model for pesticide behaviour and emissions in soil-plant systems; Descriptions of the processes in FOCUS PEARL v Alterra-rapport 013, RIVM report , Alterra, Wageningen, 107pp. Van den Berg, F. and Leistra M, Improvement of the model concept for volatilization of pesticides from soils and plant surfaces in PEARL. Description and user’s guide for PEARL C1. Beschikbaar op PEARL website: Beschikbaar op PEARL website: FOCUS_AIR_PEARL.pdfFOCUS_AIR_PEARL.pdf Van Jaarsveld, J.A., 2004: The Operational Priority Substances model; Description and validation of OPS-Pro 4.1. RIVM report /2004. RIVM, Bilthoven. FOCUS (2008). “Pesticides in Air: Considerations for Exposure Assessment”. Report of the FOCUS Working Group on Pesticides in Air (authors: R. Kubiak, L. Bürkle, I. Cousins, A. Hourdakis, T. Jarvis, B. Jene, W. Koch, J. Kreuger, W-M. Maier, M. Millet, W. Reinert, P. Sweeney, J-C. Tournayre, F. Van den Berg), EC Document Reference SANCO/10553/2006 Rev 2 (June 2008). Leistra, M.,Van der Linden, A.M.A., Boesten, J.J.T.I., and Van den Berg, F. (2001). PEARL model for pesticide behaviour and emissions in soil-plant systems; Descriptions of the processes in FOCUS PEARL v Alterra-rapport 013, RIVM report , Alterra, Wageningen, 107pp. Van den Berg, F. and Leistra M, Improvement of the model concept for volatilization of pesticides from soils and plant surfaces in PEARL. Description and user’s guide for PEARL C1. Beschikbaar op PEARL website: Beschikbaar op PEARL website: FOCUS_AIR_PEARL.pdfFOCUS_AIR_PEARL.pdf Van Jaarsveld, J.A., 2004: The Operational Priority Substances model; Description and validation of OPS-Pro 4.1. RIVM report /2004. RIVM, Bilthoven. Internal boundary layer: thickness order of m; r A depends on wind speed, atmospheric stability, temperature Surface air layer: order of mm; r B depends on air temperature Z 0M Z BL Plant r A r B Input data (scenario, application, substance) Output (targets as defined by BROWSE) Photo-transformation Droplet Plant leaf Wash-off by rain Volatilisation Penetration Further improvements in volatilisation description 1.effect of atmospheric stability 2.distinction of two-layer deposit with different exposure conditions (fully exposed vs. reduced exposure) 3.effect of leaf wetness In the short-range exposure scheme, the use of Consensus-PEARL (van den Berg and Leistra, 2004) version is the only model suggested for tier 2 by FOCUS- Air (FOCUS, 2008) as it considers not only volatilisation but also other competing processes occurring on the plant surface, The improved model concepts of Consensus-PEARL have been implemented in the new PEARL model version (the model kernel of FOCUS_PEARL 4.4.4) that has been released recently. This version of the PEARL model has been chosen as an appropriate starting point for further development within the BROWSE project. This BROWSE-PEARL version will be created specifically to address the needs of the regulator in assessing resident and bystander exposure after PPPs volatilisation from treated fields BROWSE-PEARL contains model concepts that describe in a mechanistic way the main factors controlling pesticide volatilisation from soil and plant surfaces (physicochemical properties of the compound, agricultural practices, soil physical properties, meteorological conditions during and after application) and the various competing processes that may reduce the potential amount of pesticide volatilised from the plant surface. Modelling volatilisation of PPPs from treated areas, is necessary to assess their subsequent transport downwind to potential resident and bystander locations. Although mechanistic models of the volatilisation process have been developed in the past, none of these was designed for human exposure assessment. Another possible item for improvement is the interaction between different active ingredients and its effect on the volatilisation behaviour of these ingredients. Further, the moisture condition of the deposit on the rate of volatilisation from the plant leaves has been measured to be significant. Within the BROWSE project, this aspect will be investigated further and will be taken into account in the BROWSE-PEARL model. Further analysis will include the uncertainty in the input values used for the model to describe volatilisation, the relevant competing processes on the plant surface and the uncertainty in the measured volatilisation rates. The authors gratefully acknowledge financial support by the European Commission's 7th Framework Programme, BROWSE (Bystanders, Residents, Operators and WorkerS Exposure models for plant protection products, grant agreement number ). BROWSE is a Specific Targeted Research Project that began on 1st Jan 2011 and will finish on 31st December 2013.