New Constraints on Isotopic Effects and Major Sources of Nitrate in Atmospheric Particulates by Combining δ15N and Δ17O Signatures

Abstract

AbstractParticulate nitrate () is a key component of atmospheric nitrogen (N) pollution and deposition. Stable N isotopes of can record sources of atmospheric N oxides (NOx). However, because N isotope effects between NOx and have not been constrained, the apportionment of atmospheric NOx sources remains not quantitative. By collating observation data of dual 15N and 17O isotopes and environmental parameters, we calculated values and established a new relationship to constrain values based on the 17O anomaly of . By considering values and using the Stable Isotope Analysis in the R model, we reevaluated the relative contributions between major fossil and non‐fossil fuel NOx emissions, and we found that the latter had generally higher contributions (56% ± 5%) than the former (44% ± 3%) among different sites. This study improves the isotope tracing technique of atmospheric and informs that non‐fossil fuel NOx emissions should be underscored in future emission management.