The Fourth Periodic Report on the State of Acid Deposition in East Asia Part I: Regional Assessment

The Fourth Periodic Report on the State of Acid Deposition in East Asia (PRSAD4) provides a comprehensive assessment of acid deposition and air pollution in the East Asian region based on twenty years of monitoring data (2000–2019) from the Acid Deposition Monitoring Network in East Asia (EANET). This report evaluates spatial distribution, temporal trends, and potential ecological impacts of acid deposition and related atmospheric pollutants. Key findings highlight the progress in data quality assurance, long-term monitoring of wet and dry deposition, and the effects of acidic substances on ecosystems. The report also examines regional air pollution trends, emission inventories, and health impact studies, integrating data from EANET and international sources. Additionally, it outlines methodological advancements in monitoring, modeling, and chemical transport analysis. By synthesizing scientific insights, PRSAD4 aims to enhance regional cooperation, inform policymakers, and support sustainable environmental management strategies in East Asia. The report concludes with recommendations for strengthening monitoring networks, improving emission control measures, and advancing research on acid deposition and its broader implications.