The effect of gas-phase polycyclic aromatic hydrocarbons on the formation and properties of biogenic secondary organic aerosol particles
| Autor: | Dan Imre, David M. Bell, Josef Beranek, Alla Zelenyuk, Kaitlyn J. Suski, Manish Shrivastava, Amber L. Kramer, Staci L. Massey Simonich, J. M. Wilson, M. Lizabeth Alexander |
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| Rok vydání: | 2017 |
| Předmět: |
Aerosols
Pollutant Ozonolysis Ozone Molecular Structure 010504 meteorology & atmospheric sciences Particle number Chemistry Kinetics 010501 environmental sciences behavioral disciplines and activities 01 natural sciences Article Aerosol chemistry.chemical_compound Environmental chemistry polycyclic compounds Gases Particle Size Polycyclic Aromatic Hydrocarbons Physical and Theoretical Chemistry Volatility (chemistry) Chemical decomposition 0105 earth and related environmental sciences |
| Zdroj: | Faraday Discuss |
| ISSN: | 1364-5498 1359-6640 |
| DOI: | 10.1039/c7fd00032d |
| Popis: | When secondary organic aerosol (SOA) particles are formed by ozonolysis in the presence of the gas-phase polycyclic aromatic hydrocarbons (PAHs), their formation and properties are significantly different from the SOA particles formed without PAHs. For all SOA precursors and all PAHs, discussed in this study, the presence of the gas-phase PAHs during SOA formation significantly affects particle mass loadings, composition, growth, evaporation kinetics, and viscosity. SOA particles formed in the presence of PAHs have, as part of their compositions, trapped, unreacted PAHs and products of heterogeneous reactions between PAHs with ozone. Compared to ‘pure’ SOA particles, these particles exhibit slower evaporation kinetics, have higher fractions of non-volatile components, like oligomers, and higher viscosities, assuring their longer atmospheric lifetimes. In turn, the increased viscosity and decreased volatility provide a shield that protects PAHs from chemical degradation and evaporation, allowing for the long-range transport of these toxic pollutants. The magnitude of the effect of PAHs on SOA formation is surprisingly large. The presence of PAHs during SOA formation increases mass loadings by factors of two to five, and particle number concentrations, in some cases, by more than a factor of 100. Increase in SOA mass, particle number concentrations, and lifetime has important implications to many atmospheric processes related to climate, weather, visibility, and human health, all of which relate to the interactions between biogenic SOA and anthropogenic PAHs. The synergistic relationship between SOA and PAHs presented here are clearly complex and call for future research to elucidate further the underlying processes and their exact atmospheric implications. |
| Databáze: | OpenAIRE |
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