Assessment and characterisation of the organic component of atmospheric nitrogen deposition

The organic component of atmospheric reactive nitrogen is known to be important for biogeochemical cycles, climate and ecosystems, but is still not routinely assessed in atmospheric deposition studies, and most worldwide air quality monitoring networks disregard it. Piecing together data and knowledge from diverse sources can now give a richer picture of global patterns of organic nitrogen deposition. This effort at data synthesis highlights the need for more data, but also suggests where those data gathering efforts should be focused. The development of new analytical techniques allows long-standing conjectures about the nature and sources of the organic matter to be investigated, with tantalising indications of the complex interplay between natural and anthropogenic sources, and links between the nitrogen and carbon cycles. Atmospheric emission and deposition models are needed, along with new chemical process models, to let us explore questions about the role and dynamics of organic nitrogen.