We will organize the third open science meeting in PACES (air Pollution in the Arctic: Climate, Environment and Societies) in Oslo in September 2019. PACES is a new international initiative to coordinate international and interdisciplinary research on Arctic air pollution. This workshop will foster interdisciplinary discussions on improving our predictive capability of Arctic air pollution and impacts on local societies, focusing on new understanding about sources, processes, feedbacks and impacts of Arctic air pollution. The rapid pace of Arctic environmental change puts a high priority on improving understanding of processes controlling sources and fate of Arctic air pollutants and their impacts on Arctic communities. Deficiencies in predictive capability and a lack of observations at high latitudes present major challenges to advancing this understanding, and to making credible near- and long-term projections of Arctic environmental change. The workshop will address these issues and be targeted at international scientists and experts on natural and social sciences in the Arctic including early career researchers and keynote lectures from recognized experts.