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

Masao Gen, Dan Dan Huang, Chak K. Chan

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

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 the effects of relative humidity (RH) on the reactive uptake of glyoxal (Gly) by aqueous particles of ammonium sulfate (AS), ammonium bisulfate, sodium sulfate, magnesium sulfate, ammonium nitrate (AN), and sodium nitrate. In situ Raman analysis was used to quantify particle-phase Gly and a colored product, 2,2′-biimidazole (BI), as a function of uptake time. Overall, the Gly uptake rate increases with decreasing RH, reflecting the "salting-in" effect. The BI formation rate increases significantly with decreasing RH or aerosol liquid water (ALW). Compared to that at 75% RH, the BI formation rate is enhanced by factors of 29 at 60% RH and 330 at 45% RH for AS particles and 65 at 60% RH, 210 at 45% RH, and 460 at 30% RH for AN particles. These enhancement factors are much larger than those estimated from increased reactant concentrations due to decreases in RH and ALW alone. We postulate that the reduction in ALW at low RH increases the Gly uptake rate via the "salting-in" effect and the BI formation rate by facilitating dehydration reactions.
Original languageEnglish (US)
Pages (from-to)6903-6911
Number of pages9
JournalEnvironmental Science and Technology
Volume52
Issue number12
DOIs
StatePublished - Jun 19 2018
Externally publishedYes

Bibliographical note

Generated from Scopus record by KAUST IRTS on 2023-07-06

ASJC Scopus subject areas

  • Environmental Chemistry
  • General Chemistry

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