Promoting Minamata Convention on Mercury by making the most of Japan’s knowledge and experiences: Interim project progress report

This interim progress report summarizes a pilot project conducted from August 2021 to October 2022 at the Niigata-Maki Acid Deposition Monitoring Station in Japan to assess the feasibility of integrating ambient mercury monitoring using the gold trap method into existing infrastructure. Led by the Asia Center for Air Pollution Research, the initiative followed Japanese technical guidelines and involved biweekly 24-hour sampling. The rural coastal site, influenced by seasonal monsoon winds, showed a clear seasonal pattern with higher mercury concentrations in winter, likely due to long-range transport from the Asian continent. Initial tests confirmed that sampling via manifold did not affect mercury measurements, supporting its use in routine monitoring. Practical challenges were identified, including the fragility of mercury collection tubes and the difficulty of silane treatment of quartz wool, which may hinder application in developing countries.