Formation of photochemical aerosol from hydrocarbons. Chemical reactivity and products

O’Brien, Robert; Holmes, John R.; Bockian, Albert H.

doi:10.1021/es60104a006

Cited by 51 publications

(26 citation statements)

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“…Studies in Houston using the same methods as Mylones et al have observed an organic nitrate fraction similar to the one observed in Los Angeles [50,51]. O'Brien et al [52] estimated organic nitrates constituted 17% of OA in Los Angeles in 1975. The prominence of organic nitrates in OA highlights the importance of anthropogenic emissions for this region as nitrate formation requires anthropogenic NO x or NO 3 in addition to VOCs.…”

Section: Composition Of Pm and Source Regionsmentioning

confidence: 65%

Composition and Sources of Particulate Matter Measured near Houston, TX: Anthropogenic-Biogenic Interactions

et al. 2016

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Particulate matter was measured in Conroe, Texas (~60 km north of downtown Houston, Texas) during the September 2013 DISCOVER-AQ campaign to determine the sources of particulate matter in the region. The measurement site is influenced by high biogenic emission rates as well as transport of anthropogenic pollutants from the Houston metropolitan area and is therefore an ideal location to study anthropogenic-biogenic interactions. Data from an Aerosol Chemical Speciation Monitor (ACSM) suggest that on average 64 percent of non-refractory PM 1 was organic material, including a high fraction (27%-41%) of organic nitrates. There was little diurnal variation in the concentrations of ammonium sulfate; however, concentrations of organic and organic nitrate aerosol were consistently higher at night than during the day. Potential explanations for the higher organic aerosol loadings at night include changing boundary layer height, increased partitioning to the particle phase at lower temperatures, and differences between daytime and nighttime chemical processes such as nitrate radical chemistry. Positive matrix factorization was applied to the organic aerosol mass spectra measured by the ACSM and three factors were resolved-two factors representing oxygenated organic aerosol and one factor representing hydrocarbon-like organic aerosol. The factors suggest that the measured aerosol was well mixed and highly processed, consistent with the distance from the site to major aerosol sources, as well as the high photochemical activity.

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Section: Composition Of Pm and Source Regionsmentioning

confidence: 65%

Composition and Sources of Particulate Matter Measured near Houston, TX: Anthropogenic-Biogenic Interactions

et al. 2016

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“…In this regard, the most likely candidate for generating these products are moderate molecular weight (>C 6 ) cyclic-alkenes 32 and C 8 and higher linear alkenes. 33 However, for aerosol masses produced in this work, the aerosol yield has been found 32 to be much less than 0.01, which would render at most an aerosol mass of 0.5 µg/m 3 . Moreover, if SOA products are formed from these precursors, one might also have expected to detect a higher aliphatic C-H stretch in the FTIR spectrum than was seen in the pure aromatic systems.…”

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confidence: 59%

Secondary Organic Aerosol Formation from the Irradiation of Simulated Automobile Exhaust

Kleindienst¹,

Corse²,

Li³

et al. 2002

Journal of the Air & Waste Management Association

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A laboratory study was conducted to evaluate the potential for secondary organic aerosol formation from emissions from automotive exhaust. The goal was to determine to what extent photochemical oxidation products of these hydrocarbons contribute to secondary organic aerosol (SOA) and how well their formation is described by recently developed models for SOA formation. The quality of a surrogate was tested by comparing its reactivity with that from irradiations of authentic automobile exhaust. Experiments for secondary particle formation using the surrogate were conducted in a fixed volume reactor operated in a dynamic mode. The mass concentration of the aerosol was determined from measurements of organic carbon collected on quartz filters and was corrected for the presence of hydrogen, nitrogen, and oxygen atoms in the organic species.A functional group analysis of the aerosol made by Fourier transform infrared (FTIR) spectroscopy indicated that carbonyl groups dominated the aerosol with relatively little aliphatic or aromatic C-H functionality. This result is consistent with the presence of polycarbonyl compounds measured in the aerosol. The hygroscopic potential of the aerosol was determined with the use of a liquid water content analyzer, and the analysis indicated that the aerosol uptake of water was minor at relative humidities less than 70%. The yield for the formation of SOA was found to be 1.8% when measured for an aerosol mass of 7.38 µg/m 3 . These results were compared to an aerosol model developed by Odum and coworkers and suggested that 75-85% of the fine particulate matter was due to reaction products of aromatic precursors. Organic analysis of the collected aerosol from this complex system indicates that the identified oxidation products were identical to those found in the toluene oxidation system.

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“…These include combustion analysis (O'Brien et al, 1975;Krivacsy et al, 2001;Kiss et al, 2002), electrospray ionization coupled to ultra-high-resolution mass spectrometry with (ESI) (Nguyen and Schug, 2008;Altieri et al, 2009;Bateman et al, 2009;Kroll et al, 2011;Mazzoleni et al, 2010), nuclear magnetic resonance (NMR) spectroscopy (Fuzzi et al, 2001), Fourier transform infrared spectroscopy (FTIR) (Gilardoni et al, 2009;Mysak et al, 2011), and X-ray photoelectron spectroscopy (XPS) . Gas chromatography-mass spectrometry (GC-MS) (Williams et al, 2006) and chemical ionization mass spectrometry (CIMS) with aerosol collection interface have also recently been coupled to a high-resolution time-of-flight mass spectrometer to allow for determination of elemental ratios (i.e., O : C and H : C) of organic aerosols (LopezHilfiker et al, 2014;Yatavelli and Thornton, 2010;Williams et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

et al. 2015

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Abstract. Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygento-carbon (O : C), hydrogen-to-carbon (H : C), and organic mass-to-organic carbon (OM : OC) ratios, and of carbon oxidation state (OS C ) for a vastly expanded laboratory data set of multifunctional oxidized OA standards. For the expanded standard data set, the method introduced by Aiken et al. (2008), which uses experimentally measured ion intensities at all ions to determine elemental ratios (referred to here as "Aiken-Explicit"), reproduces known O : C and H : C ratio values within 20 % (average absolute value of relative errors) and 12 %, respectively. The more commonly used method, which uses empirically estimated H 2 O + and CO + ion intensities to avoid gas phase air interferences at these ions (referred to here as "Aiken-Ambient"), reproduces O : C and H : C of multifunctional oxidized species within 28 and 14 % of known values. The values from the latter method are systematically biased low, however, with larger biases observed for alcohols and simple diacids. A detailed examination of the H 2 O + , CO + , and CO + 2 fragments in the high-resolution mass spectra of the standard compounds indicates that the Aiken-Ambient method underestimates the CO + and especially H 2 O + produced from many oxidized species. Combined AMS-vacuum ultraviolet (VUV) ionization measurements indicate that these ions are produced by dehydration and decarboxylation on the AMS vaporizer (usually operated at 600 • C). Thermal decomposition is observed to be efficient at vaporizer temperatures down to 200 • C. These results are used together to develop an "Improved-Ambient" elemental analysis method for AMS spectra measured in air. The Improved-Ambient method uses specific ion fragments as markers to correct for molecular functionality-dependent systematic biases and reproduces known O : C (H : C) ratios of individual oxidized standards within 28 % (13 %) of the known molecular values. The error in Improved-Ambient O : C (H : C) values is smaller for theoretical standard mixtures of the oxidized organic standards, which are more representative of the complex mix of species present in ambient Published by Copernicus Publications on behalf of the European Geosciences Union. M. R. Canagaratna et al.: Elemental ratio measurements of organic compoundsOA. For ambient OA, the Improved-Ambient method produces O : C (H : C) values that are 27 % (11 %) larger than previously published Aiken-Ambient values; a corresponding increase of 9 % is observed for OM : OC values. These results imply that ambient OA has a higher relative oxygen content than previously estimated. The OS C values calculated for ambient OA by the two methods agree well, however (average relative difference of 0.06 OS C units). This indicates that...

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Formation of photochemical aerosol from hydrocarbons. Chemical reactivity and products

Cited by 51 publications

References 1 publication

Composition and Sources of Particulate Matter Measured near Houston, TX: Anthropogenic-Biogenic Interactions

Composition and Sources of Particulate Matter Measured near Houston, TX: Anthropogenic-Biogenic Interactions

Secondary Organic Aerosol Formation from the Irradiation of Simulated Automobile Exhaust

Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

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