Multiphase formation of HONO formation at the air/water interface

The reaction pathways that lead to nitrous acid, HONO, are studied in many atmospheric environments due to rapid photolysis into OH and NO radicals at wavelengths below 400nm. One of the environments in which the formations of HONO is of high interest is the marine boundary layer (MBL) because of oxidation chemistry that OH and NO will undergo with the present sea spray aerosols and other trace atmospheric gases. Field studies have found that there is a peak formation of HONO in the MBL during the daytime, suggesting a photochemical pathway. Modeling studies have found that HONO formation in this environment occurs at the expense of nitrate which is relevant in the MBL because it is present in sea spray aerosols (SSA). These SSA also have other factors and components that may affect HONO formation from the photolysis of nitrate within them including pH, salt content, and organic content. The Grassian Lab is interested in determining the real-world significance of nitratephotochemistry to form HONO in the MBL by introducing these components into experimental model systems. To study this, solutions are placed in a reaction chamber with a window to allow for light irradiation and the gaseous products are flowed into an in-house made IBBCEAS that quantitatively measures HONO and NO2 simultaneously.