Nitrogen isotope composition of ammonium in PM in the Xiamen, China: impact of non-agricultural ammonia.

Since NH is a significant precursor to ammonium in PM and contributes significantly to atmospheric nitrogen deposition but largely remains unregulated in China, the insight into the source of NH emissions by the isotopic investigation is important in controlling NH emissions. In this study, atmospheric concentrations of NH and water-soluble ion composition in PM as well as nitrogen isotope ratios in NH (δN-NH) in Xiamen, China, were measured. Results showed that average NH concentration for the five sites in Xiamen was 7.