Spatial and temporal variation in fine particulate matter mass and chemical composition. A revised framework for treating primary organic aerosol. Organic aerosol component oacomp value added product. Secondary organic aerosol soa, formed in the atmosphere by oxidation of organic gases, represents a major fraction of global submicronsized atmospheric organic aerosol. In addition, both poa and soa components can be internally or externally mixed with other aerosol components and can be. In this study, a number of new instrumental methods based on liquid chromatography coupled to mass spectrometry were developed and validated to study the complex mechanisms. The formation, properties and impact of secondary organic aerosol. Investigation of high resolution mass spectrometry to. Soa formation in deliquesced ammonium sulfate aerosol is highest under lownox conditions, with acidic aerosol ph 1 and low ambient relative humidity 40%. Exposure of beas2b cells to secondary organic aerosol coated. Secondary organic aerosols soa atmospheric chemistry. A revised framework for treating primary organic aerosol emissions in inventories and models allen robinson, andrew grieshop, manish shrivastava, neil donahue, timothy lane, spyros pandis center for atmospheric particle studies carnegie mellon university presented at the 16th annual international emissions inventory conference. Recent advances in understanding secondary organic aerosol.
Atmospheric aerosol particles have a significant effect on climate. Secondary organic aerosol formation research papers. Effects of dry and wet deposition of organic vapors on secondary organic aerosol soa dry and wet deposition are the main removal pathways for soa. Hu et al modeling biogenic and anthropogenic secondary organic aerosol in china 1 introduction fast economic development and rapid industrialization and urbanization in the past several decades not only signi.
A major source of uncertainty is the formation of secondary organic aerosol soa, particulate matter that is not emitted. John seinfeld, department of chemical engineering, california institute of technology time. Physical phase transitions of secondary organic aerosol particles aki petteri pajunoja university of eastern finland, 2017 abstract aerosols fine particulate matter in air are not only important for human health but also for atmospheric processes such as cloud formation and scattering of the sunlight in the atmosphere. The formation process of secondary organic aerosols soa from oxidation of volatile organic compounds voc is currently not fully understood. Chamber studies of secondary organic aerosol formation thesis by nga lee ng in partial fulfillment of the requirements for the degree of doctor of philosophy.
Predicted change in global secondary organic aerosol. Wet scavenging is typically found to be the major direct loss 90% of soa in chemistry climate models tsigaridis et al. Application of a volatility basis set model to secondary. The metabolism and other processes controlling the release of vocs from plants are often temperature dependent. Pdf effect of chemical structure on secondary organic.
This organic aerosol comes from a variety of sources. The objective of this thesis is to contribute to t he understanding of factors important for secondary particle formation by simulating certain atmospheric processes in a flow reactor and by. The spatiotemporal distribution of oa concentrations depends on their primary emission sources, atmospheric. Higher soa levels in the atmosphere than models predicted. Analysis of secondary organic aerosol formation and aging.
Typical tropospheric temperatures render possible phase states of amorphous organic aerosol oa particles to solid, semisolid and liquid. There is a growing understanding that secondary organic aerosol soa can form through reactions in atmospheric waters i. The soa concentration is calculated by solving the eq1 and the eq2, iteratively chung and seinfeld, 2002. On a mass basis, the secondary organic aerosol soa contributed 17. Secondary organic aerosol soa is well known to have adverse effects on climate, air quality and human health. However, the dynamic mechanisms occurring during soa formation and ageing are poorly understood. Comparison of three models for secondary organic aerosol. It is estimated that 0 to 00 different organic compounds have been measured in the atmosphere goldstein and galbally, 2007.
Pm is composed of organic material, a detailed understanding of the sources and sinks of condensed organic compounds in the atmosphere is necessary to understand the effects of pm on the earths climate and human health. Aqueousphase secondary organic aerosol and organosulfate. The objective of this work is to compare the simulation results obtained with three models of secondary organic aerosol soa formation in the atmosphere. Heterogeneous oxidation of amorphous organic aerosol surrogates. Previous measurements using aerosol mass spectrometry ams indicate that pm1 in beijing is mainly. Many results were obtained using two relatively new methods for quantifying oa on time scales of minutes. Atmospheric particles compose a huge set of specific organic compounds, most of which have not been identified in field measurements. Secondary organic aerosol centre for atmospheric science. In contrast to primary organic aerosols, which are emitted directly from the biosphere, secondary organic aerosols are formed via homogeneous nucleation through the successive oxidation of gasphase organic compounds. Secondary organic aerosol how is secondary organic.
Laboratory experiments inevitably address model systems of reduced complexity to. The impact of gobi desert dust gdd particles on the secondary organic aerosol soa formation was studied to understand the photooxidation of volatile organic compounds. Ratio of concentrations of the secondary organic aerosol soa to the total organic aerosol oa as computed by a 3d global chemistry transport model for surface upper panel and zonal mean distribution lower panel for the month of july tsi. This yearlong december 2008 to december 2009 field study was conducted in an animal agriculture intensive area in. Surfaceactive om can lower aerosol surface tension, thus enhancing ccn activation however, an organic surface film can also act as a kinetic barrier for water uptake to the aerosol. This secondary organic aerosol soa can result from both anthropogenic and biogenic sources. Near surface organic aerosol concentrations, daily averaged. Organic aerosol is an important fraction of the fine particulate matter present in the atmosphere. Characterizing the formation of secondary organic aerosols. Oa is composed of a mixture of primary emitted organic matter poa and secondary organic aerosols soa formed by gastoparticle conversion.
Aging of organic aerosols is caused by oh radicals date. Study of organic carbon oc and elemental carbon ec in pm. Pdf aqueous chemistry and its role in secondary organic. Kanakidou et al organic aerosol and global climate modelling fig. View secondary organic aerosol formation research papers on academia. Chemical processing of organic material in aqueous atmospheric aerosols and cloudwater is known to form secondary organic. Secondary organic aerosol production in laboratory. Primary aerosol sources of dicarboxylic acids in atmospheric aerosols include ocean emissions, engine exhausts and biomass burn ing. These results support that mnp can effectively deliver soas to epithelial cells in vitro resulting in a significant biological effects.
We need to understand the complete life cycle of the vocsoa system. However, our capability to accurately predict these is currently hampered by relative scarcity of the detailed measurements needed in many environments and a lack of mechanistic understanding of the. The formation, properties and impact of secondary organic. Comparison of three models for secondary organic aerosol formation in the atmosphere christian seigneur and betty pun. A secondary organic aerosol soa is a molecule produced via oxidation over several generations of a parent organic molecule. The fundamental concept on which all descriptions of soa formation lies is that soa comprises a mixture of semivolatile organic compounds that partition becorrespondence to. Secondary organic aerosol soa, a prominent fraction of particulate. Pdf secondary organic aerosol formation and primary. Exploring sources of biogenic secondary organic aerosol. Characterisation of the ambient aerosol composition has shown that as much as 50% of the mass can be organic and that a considerable fraction of the organic matter is of secondary biogenic origin kanakidou et al. Pdf ozone and secondary organic aerosol formation of. Laboratory chamber experiments do not account fully for ambient aging. In clouds and wet aerosols, watersoluble organic products of gasphase photochemistry dissolve into the aqueous phase where they can react further e. Modeling anthropogenically controlled secondary organic.
Strong anthropogenic control of secondary organic aerosol. The oxidation of organics in aerosol particles affects the physical properties of aerosols through a process known as aging. Gasphase oxidation processes are key in soa formation, but there is increasing evidence that chemistry occur. Physical properties and processes of secondary organic. The complexity of the situation is compounded further by. Organic aerosol particles and components originate from both direct emissions primary organic aerosol, poa as well as chemical reactions and gastoparticle conversion in the atmosphere secondary organic aerosol, soa. Modeling biogenic and anthropogenic secondary organic. Secondary organic aerosols represent a major component of atmospheric particulates, affecting the global radiation budget through the direct and indirect effects. We have examined aqueousphase secondary organic aerosol soa and organosulfate os formation in atmospheric aerosols using a photochemical box model with coupled gasphase chemistry and detailed aqueous aerosol chemistry. Impact of aerosolcloud cycling on aqueous secondary organic. Organic aerosol material oa, a common component of tropospheric aerosols, is typically more hydrophobic, and therefore less hygroscopic than inorganic salts. A revised framework for treating primary organic aerosol emissions in inventories and models allen l. Primary and secondary organic aerosol origin by combined gas. Secondary organic aerosol formation and primary organic aerosol oxidation from biomassburning smoke in a flow reactor during flame3.
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