The atmospheric nitrogen question

Chemical plant at night

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Pollutants, key atmospheric components and vital fertilisers: nitrogen compounds are all of these, as Emma Davies finds out

Nitrogen oxides (NO and NO2; NOx) have a bad press, particularly in the wake of the vehicle emissions scandal. But they are just a small part of a highly complex nitrogen cycle, which controls a vast range of atmospheric processes, many of which are linked to climate change and adverse human health effects. From agricultural ammonia emissions to cars belching NOx, the cycle has been studied in a fragmented way but there are now calls to unite researchers to help deliver what policy-makers need to know.