The APIS programme are undertaking some development work and new modelling for attributing pollutant sources across the UK and protected network. Source Attribution data provides a snapshot of the mix of pollutant deposition by source sector emissions over a 5km grid or protected site in the UK. As part of this new work we would like to hear your views on the current source attribution data and how it is used in APIS. The survey https://ceh-online-surveys.onlinesurveys.ac.uk/source-attribution-survey-apis will take you around 10 minutes to complete. Your answers are important for the APIS steering group to more fully utilise source attribution data across the UK and protected site network.