Unveiling the underestimated direct emissions of nitrous acid (HONO).

ABSTRACT: Gaseous nitrous acid (HONO) is a critical source of hydroxyl radicals (OH) in the troposphere. While both direct and secondary sources contribute to atmospheric HONO, direct emissions have traditionally been considered minor contributors. In this study, we developed δ¹⁵N and δ¹⁸O isotopic fingerprints to identify six direct HONO emission sources and conducted a 1-y case study on the isotopic composition of atmospheric HONO at rural and urban sites. Interestingly, we identified that livestock farming is a previously overlooked direct source of HONO and determined its HONO to ammonia (NH₃) emission ratio. Additionally, our results revealed that spatial and temporal variations in atmospheric HONO isotopic composition can be partially attributed to direct emiss

SUBMITTER: Zhang Q 

PROVIDER: S-EPMC10468620 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature