An investigation into the chemistry of HONO in the marine boundary layer at Tudor Hill Marine Atmospheric Observatory in Bermuda

Abstract. Here we present measurement results of temporal distributions of nitrous acid (HONO) along with several chemical and meteorological parameters during the spring and the late summer of 2019 at Tudor Hill Marine Atmospheric Observatory in Bermuda. Large temporal variations in HONO concentration were controlled by several factors including local pollutant emissions, air mass interaction with the island, and long-range atmospheric transport of HONO precursors. In polluted plumes emitted from local traffic, power plant and cruise ship emissions, HONO and nitrogen oxides (NOx) existed at substantial levels (up to 278 pptv and 48 ppbv, respectively) and NOx-related reactions played dominant roles in daytime formation of HONO. The lowest concentration of HONO was observed in marine air, with median concentrations at ~3 pptv around solar noon and