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Molecular Composition and Volatility of Nucleated Particles from α-Pinene Oxidation between -50 °c and +25 °c

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Details

Original languageEnglish
Pages (from-to)12357-12365
Number of pages9
JournalEnvironmental Science and Technology
Volume53
Issue number21
DOIs
Publication statusPublished - 5 Nov 2019
Externally publishedYes
Publication typeA1 Journal article-refereed

Abstract

We use a real-time temperature-programmed desorption chemical-ionization mass spectrometer (FIGAERO-CIMS) to measure particle-phase composition and volatility of nucleated particles, studying pure α-pinene oxidation over a wide temperature range (-50 °C to +25 °C) in the CLOUD chamber at CERN. Highly oxygenated organic molecules are much more abundant in particles formed at higher temperatures, shifting the compounds toward higher O/C and lower intrinsic (300 K) volatility. We find that pure biogenic nucleation and growth depends only weakly on temperature. This is because the positive temperature dependence of degree of oxidation (and polarity) and the negative temperature dependence of volatility counteract each other. Unlike prior work that relied on estimated volatility, we directly measure volatility via calibrated temperature-programmed desorption. Our particle-phase measurements are consistent with gas-phase results and indicate that during new-particle formation from α-pinene oxidation, gas-phase chemistry directly determines the properties of materials in the condensed phase. We now have consistency between measured gas-phase product concentrations, product volatility, measured and modeled growth rates, and the particle composition over most temperatures found in the troposphere.

ASJC Scopus subject areas

Publication forum classification

Field of science, Statistics Finland