AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Characterization of the Heterogeneous Reactivity of Alpha-Pinene Oxidation Products with Dimethylamine and Ammonia
MATTHIEU RIVA, Geoffroy Duporte, Jevgeni Parshintsev, Otso Peräkylä, Liine Heikkinen, Eva Canaval, Enna Heikkinen, Luis Barreira, Nana Myllys, Kari Hartonen, Markku Kulmala, Armin Hansel, Marja-Liisa Riekkola, Mikael Ehn, University of Helsinki
Abstract Number: 93 Working Group: Aerosol Chemistry
Abstract Amines are emitted to the atmosphere from industry, combustion, biomass burning, animal husbandry and oceans. These compounds are ubiquitous in the atmosphere and observed in several locations in the world. In addition, ammonium salts have been identified as a major component of atmospheric aerosol. Amines and ammonia are recognized to affect the chemistry and lifecycle of atmospheric aerosols, especially due to their unique acid-neutralizing capacity. Recently, a few studies have highlighted the role of amines in the formation and growth of secondary organic aerosol (SOA). It has also been demonstrated that carbonyl compounds, such as glyoxal, can react with amines and/or ammonia leading to the formation of N-containing species and oligomers, which could further impact SOA formation and the optical properties of the aerosols.
In the present work, the heterogeneous reactivity of dimethylamine and ammonia with the products generated from the ozonolysis of alpha-pinene was investigated. Experiments were performed using a flow tube reactor to chemically characterize the reactivity of dimethylamine (DMA) while the reactivity of ammonia with alpha-pinene oxidation products was carried out in a 2-m3 Teflon chamber. In the chamber experiments, size-selected ammonium sulfate particles were injected under dry and wet conditions. Gaseous organic compounds were chemically characterized using a time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) with iodide (I−) ionization sources, and a proton transfer time-of-flight mass spectrometer (PTR3). In addition, particle-phase was chemically characterized using Filter Inlet for Gases and AEROsols (FIGAERO) coupled to an I−-HR-ToF-CIMS and using ultra-high-performance liquid chromatography coupled an Orbitrap mass spectrometer (UHPLC-HRMS) for the flow tube experiments only. Heterogeneous reactions between ozonolysis oxidation products of alpha-pinene, such as pinonaldehyde, and DMA or ammonia were observed. N-containing species as well as volatile unsaturated products were identified in both phases suggesting that such reactivity could further impact SOA composition and ozone concentration.