Governing processes for reactive nitrogen compounds in the European atmosphere

摘要: Abstract. Reactive nitrogen (Nr) compounds have different fates in the atmosphere due to differences governing processes of physical transport, deposition and chemical transformation. Nr addressed here include reduced (NHx: ammonia (NH3) its reaction product ammonium (NH4p)), oxidized (NOy: monoxide (NO) p dioxide (NO2) their products) as well organic (organic N). Pollution abatement strategies need take into account these when assessing impact on ecosystem services, biodiversity, human health climate. NOx (NO NO2) emitted from traffic affects urban areas where presence buildings increases residence time streets. In this leads enhanced exposure population concentrations. emissions generally little nearby ecosystems because small dry rates NOx. These be converted nitric acid (HNO3) before removal through is efficient. HNO3 sticks quickly any surface thereby either deposited or incorporated aerosols nitrate (NO3−). contrast compounds, NH3 has potentially high impacts near main agricultural sources large ground-level concentrations along with rates. Aerosol phase NH4p NO3− contribute significantly background PM2.5 PM10 (mass an aerodynamic diameter less than 2.5 10 μm, respectively) radiation balance health. Little known quantitatively qualitatively about N atmosphere, other that it contributes a significant fraction wet-deposited N, present both gaseous particulate forms. Further studies are needed characterise sources, air chemistry emissions.