The Expert Team on Atmospheric Composition Prediction System (ET-ACPS) reviews and updates WIPPS guidance materials (WMO-No. 485 and WMO-No. 305), ensures WIPPS Designated Centres comply with quality standards, analyzes gaps in atmospheric composition forecasting (including sand and dust, vegetation fires, and related phenomena), and provides guidance on verification methods. The team supports capacity building, evaluates advances in forecast models and systems, coordinates technical capabilities and emerging infrastructure needs of WIPPS-DCs.