Influence of NOx emissions from ships on tropospheric photochemistry and climate

摘要: Emissions of nitrogen oxides (NOx, the sum NO and NO2) from fossil-fuel burning dominate NOx burden lower troposphere in many regions1. These emissions increase tropospheric ozone hydroxyl-radical concentrations over their natural ‘background’ levels, thereby increasing oxidizing power atmosphere2. Fossil-fuel (refs 3, 4) account for about half global source to atmosphere; other significant sources are biomass burning5, soil emissions6, aircraft exhausts7 lightning8, all primarily continental. However, ocean-going ships fossil fuels may also contribute a fraction (>10%) production9. Here we use emission data high-resolution chemistry–transport model estimate that ship result more than 100-fold surface heavily traversed ocean regions. This enhancement has notable effect on modelled concentrations. In particular, predicted fivefold July northern Atlantic Pacific oceans would be expected reduce atmospheric lifetimes reactive greenhouse gases—such as methane—as well aerosol production rates cloud reflectivities, therefore exerting cooling influence climate.