Atmospheric NOx oxidation as major sources for nitrous acid (HONO)

Abstract Nitrous acid (HONO) is the major precursor of hydroxyl (OH) radicals to initiate tropospheric chemistry leading formation secondary pollutants. The sources atmospheric HONO, however, are not fully understood. Here we show two additional HONO that stem from oxidation nitrogen oxide (NO x = NO + 2 ). Nitric (HNO 3 ) formed photooxidation can be converted into with a yield ~53%, and dark by in presence H O produces 2%. diurnal variations levels field observations urban (Beijing) rural (Wangdu) areas North China Plain well reproduced WRF-Chem model when new taken account. findings imply pathways for which significantly accelerate ozone polluted regions as well.