Air emissions of nitrogen oxides from ship traffic in the Baltic Sea are a health concern in coastal areas of the Baltic Sea region. We find that the introduction of the nitrogen emission control area (NECA) is critical for reducing ship emissions of nitrogen oxides to levels that are low enough to sustainably dampen ozone production. The decline of the ship-related nitrogen deposition to the Baltic Sea between 2012 and 2040 varies between 46 % and 78 % in different regulation scenarios.