Over the past 50 years, the field of environmental sciences has witnessed remarkable progress driven by advancements in analytical instrumentation and monitoring technologies. These advancements have revolutionized our capability to detect, quantify and characterize both legacy pollutants and contaminants of emerging concern (CECs) at ultra-low concentrations. They have also enabled the development of sophisticated tools for contaminant source tracking and environmental risk assessment. Robust environmental monitoring of priority pollutants and CECs plays a crucial role in water quality management. By identifying pollution issues, these measurements support efforts to improve water quality, and safeguard aquatic ecosystems and human health. As Professor Peter Drucker famously stated, "If you can't measure it, you can't improve it." Therefore, the mission of environmental authorities, practitioners, and researchers should be centered around the principle of "Measure to Improve."
This lecture will showcase successful case studies from Hong Kong, China that exemplify how environmental quality improvements can be achieved through informed management interventions. Additionally, the presentation will address the urgent global challenges posed by marine pollution, emphasizing the critical need for enhanced international collaboration and coordinated solutions. Lastly, I will introduce several prominent global initiatives, including the World Harbor Project, the Global Monitoring of Pharmaceuticals Project, and the Global Estuaries Monitoring (GEM) Program. The GEM Program is a Decade Action endorsed by the UN Decade of Ocean Science for Sustainable Development (2021-2030). This program aims to establish a comprehensive global network for pollution monitoring, unravel the pollution status of estuaries worldwide, and co-design solutions to combat marine pollution, ultimately making our estuaries cleaner and safer for all. I hope this presentation will inspire the audience to join in the collective efforts towards achieving ocean optimism.

Ocean optimism,Contaminants of emerging concern,Environmental quality,Marine pollution