Photochemical organonitrate formation in wet aerosols
Other literature type
Lim, Yong Bin
Kim, Jin Young
Turpin, Barbara J.
(issn: 1680-7324, eissn: 1680-7324)
Water is the most abundant component of atmospheric fine aerosol. However,
despite rapid progress, multiphase chemistry involving wet aerosols is still
poorly understood. In this work, we report results from smog chamber
photooxidation of glyoxal- and OH-containing ammonium sulfate or sulfuric
acid particles in the presence of NO<sub><i>x</i></sub> and O<sub>3</sub> at high and low relative humidity. Particles were analyzed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry
During the 3 h irradiation, OH oxidation products of glyoxal that are also produced in dilute aqueous solutions (e.g., oxalic acids and tartaric acids) were formed in both ammonium sulfate (AS) aerosols and sulfuric acid (SA) aerosols. However, the major products were organonitrogens (CHNO), organosulfates (CHOS), and organonitrogen sulfates (CHNOS). These were also the dominant products formed in the dark chamber, indicating non-radical formation. In the humid chamber (> 70 % relative humidity, RH), two main products for both AS and SA aerosols were organonitrates, which appeared at <i>m</i> ∕ <i>z</i><sup>−</sup> 147 and 226. They were formed in the aqueous phase via non-radical reactions of glyoxal and nitric acid, and their formation was enhanced by photochemistry because of the
photochemical formation of nitric acid via reactions of peroxy radicals,
NO<sub><i>x</i></sub> and OH during the irradiation.