Sunlight, a natural source of nitrous oxide

Chemical and Engineering News is reporting that scientists have discovered a new natural pathway resulting in the production of the greenhouse gas nitrous oxide.  The research shows that small airborne particles containing ammonium nitrate were undergoing a chemical reaction caused by sunlight.  This research is interesting in that it accounts for nitrous oxide in the air that previously had no explainable source.  A larger and related source of nitrous oxide that was already understood was the biological degradation of ammonium nitrate fertilizer on farmland.