The annual meeting of the Task Force on Hemispheric Transport of Air Pollution (TF HTAP) under the UNECE Air Convention took place in Hamburg, Germany, on 8-9 April 2026. Representatives of the Meteorological Synthesizing Centre – East (MSC-E) attended the meeting, presenting progress in ongoing activities and contributing to discussions on current research topics and future plans.

TF HTAP is an international scientific initiative dedicated to improving understanding of intercontinental air pollution transport across the Northern Hemisphere and beyond. The meeting reviewed progress and outlined future work within four key research activities: OPNS (ozone, particles, and nitrogen and sulphur deposition), HTAP-Fires (wildfire impacts on air quality), MCHgMAP (mercury trends and source attribution), and HTAP-PFAS (emerging issues related to per- and polyfluoroalkyl substances).

MSC-E organised and chaired the session on the Multi-Compartment Mercury Modelling and Analysis Project (MCHgMAP), which supports the effectiveness evaluation of both the Air Convention and the Minamata Convention on Mercury. The session focused on results from the first phase of the project. Jan Gačnik presented analysis of reactive mercury in the atmosphere based on corrected observational data and model ensemble simulations, while Oleg Travnikov provided an overview of the project, key findings, and future plans.

MSC-E also contributed to discussions on the HTAP-Fires activity. Reza Gholizadeh presented an analysis of available emission inventories of dioxins and furans (PCDD/Fs), along with initial global simulations and plans for further work.

In addition, MSC-E participated in the session on the newly launched HTAP-PFAS initiative, contributing to discussions on available data, modelling approaches, and the development of a future simulation programme, as well as round-table exchanges on potential policy and research applications.