Ambient Gas-Particle Partitioning of Tracers for Biogenic Oxidation.
Environ Sci Technol
; 50(18): 9952-62, 2016 09 20.
Article
em En
| MEDLINE
| ID: mdl-27552285
ABSTRACT
Exchange of atmospheric organic compounds between gas and particle phases is important in the production and chemistry of particle-phase mass but is poorly understood due to a lack of simultaneous measurements in both phases of individual compounds. Measurements of particle- and gas-phase organic compounds are reported here for the southeastern United States and central Amazonia. Polyols formed from isoprene oxidation contribute 8% and 15% on average to particle-phase organic mass at these sites but are also observed to have substantial gas-phase concentrations contrary to many models that treat these compounds as nonvolatile. The results of the present study show that the gas-particle partitioning of approximately 100 known and newly observed oxidation products is not well explained by environmental factors (e.g., temperature). Compounds having high vapor pressures have higher particle fractions than expected from absorptive equilibrium partitioning models. These observations support the conclusion that many commonly measured biogenic oxidation products may be bound in low-volatility mass (e.g., accretion products, inorganic-organic adducts) that decomposes to individual compounds on analysis. However, the nature and extent of any such bonding remains uncertain. Similar conclusions are reach for both study locations, and average particle fractions for a given compound are consistent within â¼25% across measurement sites.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Compostos Orgânicos
/
Aerossóis
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article