PM₂.₅ and Ozone Co-Control - Policy Brief

This brief presents a policy brief that examines the need to jointly control fine particulate matter with a diameter of less than 2.5 micrometers and photochemical oxidants represented by ozone in Asian urban and suburban contexts. It explains that these pollutants are the dominant contributors to adverse human health outcomes and are increasingly formed through interconnected atmospheric chemical processes rather than direct emissions. The brief describes seasonal patterns, precursor interactions, and the shift from primary to secondary pollutant formation as emission controls advance. It outlines a coordinated control framework focusing on simultaneous reduction of sulfur dioxide, nitrogen oxides, volatile organic compounds, and ammonia.