Germinating wheat promotes the emission of atmospherically significant nitrous acid (HONO) gas from soils

Abstract

Tropospheric removal of pollutants initiated by the hydroxyl radical (OH) is a key process in atmospheric chemistry. In the lower atmosphere, OH production is linked to photolysis of nitrous acid (HONO), and it has been suggested that soil contributes strongly to the production of atmospheric HONO. However, factors controlling HONO production in soils are poorly known. We report here for the first time that HONO production in agricultural soil is potentially related to the germination and early development stages of wheat. Nitrite (NO2−) released from the germinating seeds increased the HONO production. Given the significant area of agricultural lands globally, the emission of HONO from initial growth phase of wheat must be considered as a mechanism contributing to the OH production in the atmosphere.