Apportionment of Primary and Secondary Organic Aerosols in Southern California during the 2005 Study of Organic Aerosols in Riverside (SOAR-1)

Docherty, Kenneth S.; Stone, Elizabeth A.; Ulbrich, I. M.; DeCarlo, P. F.; Snyder, David C.; Schauer, James J.; Peltier, Richard E.; Weber, R. J.; Murphy, S. M.; Seinfeld, John H.; Grover, Brett D.; Eatough, Delbert J.; Jimenez, José L.

doi:10.1021/es8008166

Cited by 287 publications

(306 citation statements)

References 57 publications

(127 reference statements)

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“…[27] From Figure 5d, if total OOA is taken as a surrogate for SOA, and the sum of HOA, CIOA, and LOA is taken as a surrogate for POA, then it can be concluded that SOA is dominant at the Pasadena ground site, which is consistent with earlier findings in Riverside, CA [Docherty et al, 2008].…”

Section: Source Apportionment Of Organic Aerosol Mass By Positive Matsupporting

confidence: 82%

Organic aerosol composition and sources in Pasadena, California, during the 2010 CalNex campaign

et al. 2013

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Organic aerosols (OA) in Pasadena are characterized using multiple measurements from the California Research at the Nexus of Air Quality and Climate Change (CalNex) campaign. Five OA components are identified using positive matrix factorization including hydrocarbon‐like OA (HOA) and two types of oxygenated OA (OOA). The Pasadena OA elemental composition when plotted as H : C versus O : C follows a line less steep than that observed for Riverside, CA. The OOA components from both locations follow a common line, however, indicating similar secondary organic aerosol (SOA) oxidation chemistry at the two sites such as fragmentation reactions leading to acid formation. In addition to the similar evolution of elemental composition, the dependence of SOA concentration on photochemical age displays quantitatively the same trends across several North American urban sites. First, the OA/ΔCO values for Pasadena increase with photochemical age exhibiting a slope identical to or slightly higher than those for Mexico City and the northeastern United States. Second, the ratios of OOA to odd‐oxygen (a photochemical oxidation marker) for Pasadena, Mexico City, and Riverside are similar, suggesting a proportional relationship between SOA and odd‐oxygen formation rates. Weekly cycles of the OA components are examined as well. HOA exhibits lower concentrations on Sundays versus weekdays, and the decrease in HOA matches that predicted for primary vehicle emissions using fuel sales data, traffic counts, and vehicle emission ratios. OOA does not display a weekly cycle—after accounting for differences in photochemical aging —which suggests the dominance of gasoline emissions in SOA formation under the assumption that most urban SOA precursors are from motor vehicles.

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Section: Source Apportionment Of Organic Aerosol Mass By Positive Matsupporting

confidence: 82%

Organic aerosol composition and sources in Pasadena, California, during the 2010 CalNex campaign

et al. 2013

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“…We applied the different methods for ON and OS estimation to ambient HR-AMS data acquired in Riverside, CA during the SOAR-1 campaign (30). OA was dominated by SOA (30), and the combination of high NO x and VOC concentrations should result in significant ON production. A comparison between the AMS PM 1 nitrate and ion chromatography (IC) PM 2.5 nitrate reveals agreement within the errors, which confirms that the majority of the AMS nitrate is inorganic (Fig.…”

Section: Discussionmentioning

confidence: 99%

Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry

Farmer

Matsunaga

Docherty

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

527

562

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Organonitrates (ON) are important products of gas-phase oxidation of volatile organic compounds in the troposphere; some models predict, and laboratory studies show, the formation of large, multifunctional ON with vapor pressures low enough to partition to the particle phase. Organosulfates (OS) have also been recently detected in secondary organic aerosol. Despite their potential importance, ON and OS remain a nearly unexplored aspect of atmospheric chemistry because few studies have quantified particulate ON or OS in ambient air. We report the response of a high-resolution time-of-flight aerosol mass spectrometer (AMS) to aerosol ON and OS standards and mixtures. We quantify the potentially substantial underestimation of organic aerosol O/C, commonly used as a metric for aging, and N/C. Most of the ONnitrogen appears as NO þ x ions in the AMS, which are typically dominated by inorganic nitrate. Minor organonitrogen ions are observed although their identity and intensity vary between standards. We evaluate the potential for using NO þ x fragment ratios, organonitrogen ions, HNO þ 3 ions, the ammonium balance of the nominally inorganic ions, and comparison to ion-chromatography instruments to constrain the concentrations of ON for ambient datasets, and apply these techniques to a field study in Riverside, CA. OS manifests as separate organic and sulfate components in the AMS with minimal organosulfur fragments and little difference in fragmentation from inorganic sulfate. The low thermal stability of ON and OS likely causes similar detection difficulties for other aerosol mass spectrometers using vaporization and/or ionization techniques with similar or larger energy, which has likely led to an underappreciation of these species.atmospheric chemistry | organic aerosol | organic nitrate | organic sulfate | SOA O rganonitrates (ON, i.e., RONO 2 ) and organosulfates (OS, i.e., ROSO 3 H) are known to be present in secondary organic aerosol (SOA) (1-4), and are a nearly unexplored but potentially important aspect of atmospheric chemistry. The mechanisms behind ON and OS production and aging are poorly understood and generally ignored in models due in part to a lack of measurement approaches. ON have recently been identified as significant components (15-35%) of NO y in the gas-phase (5, 6) and serve as indicators of ozone production (7). Oceans and certain industrial processes directly emit ON, but these are generally short-chain alkyl nitrates that exist only in the gas-phase and constitute a minor fraction of atmospheric ON (6,8). Most atmospheric ON are produced either by photochemical (OH-initiated) or nocturnal (NO 3 -initiated) oxidation reactions of anthropogenic and biogenic volatile organic compounds (VOCs). These reactions can produce large, multifunctional ON with vapor pressures potentially low enough to condense and form SOA. During photochemical oxidation of VOCs in the presence of nitrogen oxides, ON are minor products of peroxy radical ðRO 2 Þ þ NO reactions. These reactions produce ON with yields of ...

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“…Predictions from the SOM model were compared to measurements made by the aerosol mass spectrometer (AMS) during the Study of Organic Aerosols at Riverside (SOAR) in the summer of 2005 (Docherty et al, 2011(Docherty et al, , 2008. Over the 2-week simulation, the SOM model underpredicted total OA by 40 % at this location.…”

Section: Soa Concentrations and Precursor-resolved Compositionmentioning

confidence: 99%

Multi-generational oxidation model to simulate secondary organic aerosol in a 3-D air quality model

et al. 2015

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Abstract. Multi-generational gas-phase oxidation of organic vapors can influence the abundance, composition and properties of secondary organic aerosol (SOA). Only recently have SOA models been developed that explicitly represent multigenerational SOA formation. In this work, we integrated the statistical oxidation model (SOM) into SAPRC-11 to simulate the multi-generational oxidation and gas/particle partitioning of SOA in the regional UCD/CIT (University of California, Davis/California Institute of Technology) air quality model. In the SOM, evolution of organic vapors by reaction with the hydroxyl radical is defined by (1) the number of oxygen atoms added per reaction, (2) the decrease in volatility upon addition of an oxygen atom and (3) the probability that a given reaction leads to fragmentation of the organic molecule. These SOM parameter values were fit to laboratory smog chamber data for each precursor/compound class. SOM was installed in the UCD/CIT model, which simulated air quality over 2-week periods in the South Coast Air Basin of California and the eastern United States. For the regions and episodes tested, the two-product SOA model and SOM produce similar SOA concentrations but a modestly different SOA chemical composition. Predictions of the oxygen-tocarbon ratio qualitatively agree with those measured globally using aerosol mass spectrometers. Overall, the implementation of the SOM in a 3-D model provides a comprehensive framework to simulate the atmospheric evolution of organic aerosol.

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Apportionment of Primary and Secondary Organic Aerosols in Southern California during the 2005 Study of Organic Aerosols in Riverside (SOAR-1)

Cited by 287 publications

References 57 publications

Organic aerosol composition and sources in Pasadena, California, during the 2010 CalNex campaign

Organic aerosol composition and sources in Pasadena, California, during the 2010 CalNex campaign

Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry

Multi-generational oxidation model to simulate secondary organic aerosol in a 3-D air quality model

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