Atmospheric organic nitrogen deposition in China

Precipitation samples have been collected and analyzed for organic and inorganic nitrogen (N) at 32 sites in China from 2005 to 2009. Our results suggest that dissolved organic nitrogen (DON) accounts for 28% of the total atmosphere bulk N deposition. Average annual DON deposition was 6.84 kg N ha−1 yr−1, ranging from 1.01 to 19.7 kg N ha−1 yr−1. The volume weighted average DON concentration was 77 μmol L−1, ranging from 13 to 190 μmol L−1, which was much higher than results obtained in other regions of the world. Analysis of seasonal variations of DON concentration, deposition, the ratio of DON to total dissolved N (TDN), rainfall and wind frequency roses revealed possible pollution sources in specific regions, e.g. agriculture, oceanic spray and re-suspension. Significant correlations of DON with TDN from results in this study and elsewhere indicate that atmospheric organic N species have similar anthropogenic pollution sources to atmospheric inorganic N species, and that DON deposition is an important part of the TDN deposition.