Across the EU, Spray drift deposition may vary significantly due to differences in crops, agronomic practices and agro-environmental conditions. Currently, the Ganzelmeier-Rautmann drift deposition curves are generally used for regulatory exposure assessments in the EU. However, these curves may not adequately represent the diverse meteorological and crop conditions and technologies across Europe.

Advanced modelling offers an alternative to experimental drift curves for regulatory purposes, if such models would exist for upward and sideways (U&S) sprayed crops at the EU level. The model SPEXUS, developed for Dutch apple orchards, was compared to six EU datasets, covering several crops and EU regulatory zones. The
comparison showed that model predictions differed from experimental deposits but responses to varying experimental conditions were similar.

The Ganzelmeier-Rautmann curves often overestimated the measured drift deposits, and therefore usually remains a conservative approach from a regulatory perspective. Advanced models offer clear advantages in describing spray drift by accounting for variable weather, application techniques, crop types and structures. Development of such models represents a promising path towards an EU-wide framework for spray drift predictions in U&S sprayed crops.