Air pollution is a global challenge to people’s health and has severe economic consequences. The region of Northeast Asia is no exception. Across most regions in Japan, and in the entire territories of Korea and China, annual average concentrations of fine particulate matter are above the guideline levels indicated by the World Health Organisation, indicating a risk to health. Policy action to tackle air pollution across the three countries, could prevent air pollution related illnesses and deaths, without affecting economic growth. This report presents projections for the impact of air pollution polices until 2050, with differing levels of regional coordination. Projections for current policies are compared with unilateral policy action, whereby each of the three countries introduce more stringent policies to tackle air pollution; alongside regionally coordinated policy action by all three countries; and policy action on a global level. The report presents the health, agricultural and economic impacts, and identifies considerable benefits from further coordination on air pollution policies, such as with regional and global policy action.