Reactive Uptake of Glyoxal by Ammonium-Containing Salt Particles as a Function of Relative Humidity

• DOI: 10.1021/acs.est.8b00606
• Publication Date: 2018-05-18T20:04:48Z
• Authors: Masao Gen; Dan Dan Huang; Chak K. Chan
• Keywords: Ammonium sulfate; Glyoxal; Sodium sulfate; Ammonium nitrate; Salting out

Reactions between dissolved ammonia and carbonyls, which form light-absorbing species in atmospheric particles, can be accelerated by actively removing water from the reaction system. Here, we examine effects of relative humidity (RH) on reactive uptake glyoxal (Gly) aqueous particles ammonium sulfate (AS), bisulfate, sodium sulfate, magnesium nitrate (AN), nitrate. In situ Raman analysis was used to quantify particle-phase Gly a colored product, 2,2′-biimidazole (BI), as function time. Overall, rate increases with decreasing RH, reflecting "salting-in" effect. The BI formation significantly RH or aerosol liquid (ALW). Compared that at 75% is enhanced factors 29 60% 330 45% for AS 65 210 460 30% AN particles. These enhancement are much larger than those estimated increased reactant concentrations due decreases ALW alone. We postulate reduction low via effect facilitating dehydration reactions.