title: Dimethylamine as a major alkyl amine species in particles and cloud water: Observations in semi-arid and coastal regions.
abstract: Aerosol and cloud water measurements of dimethylamine (DMA), the most abundant amine in this study, were conducted in semi-arid (Tucson, Arizona) and marine (Nucleation in California Experiment, NiCE; central coast of California) areas. In both regions, DMA exhibits a unimodal aerosol mass size distribution with a dominant peak between 0.18 and 0.56 μm. Particulate DMA concentrations increase as a function of marine biogenic emissions, sulfate, BVOC emissions, and aerosol-phase water. Such data supports biogenic sources of DMA, aminium salt formation, and partitioning of DMA to condensed phases. DMA concentrations exhibit positive correlations with various trace elements and most especially vanadium, which warrants additional investigation. Cloud water DMA levels are enhanced significantly during wildfire periods unlike particulate DMA levels, including in droplet residual particles, due to effective dissolution of DMA into cloud water and probably DMA volatilization after drop evaporation. DMA:NH+4molar ratios peak between 0.18 and 1.0 μm depending on the site and time of year, suggesting that DMA competes better with NH3in those sizes in terms of reactive uptake by particles.
authors.affiliation: Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA.
authors.forename: J-S
authors.initials: JS
authors.lastname: Youn
authors.affiliation: Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA.
authors.forename: E
authors.initials: E
authors.lastname: Crosbie
authors.affiliation: Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA.
authors.forename: L C
authors.initials: LC
authors.lastname: Maudlin
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA; Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA; Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA.
authors.forename: A
authors.initials: A
authors.lastname: Sorooshian
keywords: Aerosol; Amines; Biomass burning; Cloud water; Dimethylamine; MOUDI; Marine