Comments on “Estimated Gas-Phase Standard State Enthalpies of Formation for Organic Compounds Using the Gaussian-4 (G4) and W1BD Theoretical Methods” (Rayne, S.; Forest, K.J. Chem. Eng. Data2010,55, 5359−5364)

2011 ◽  
Vol 56 (3) ◽  
pp. 682-683 ◽  
Author(s):  
Olga V. Dorofeeva
Keyword(s):  
Gas Phase ◽  
Organic Compounds ◽  
Enthalpies Of Formation ◽  
Standard State ◽  
Theoretical Methods

The rate of photocatalytic oxidation of aromatic volatile organic compounds in the gas-phase

2008 ◽  
Vol 42 (34) ◽  
pp. 7844-7850 ◽  
Author(s):  
Aikaterini K. Boulamanti ◽  
Christos A. Korologos ◽  
Constantine J. Philippopoulos
Keyword(s):  
Volatile Organic Compounds ◽  
Gas Phase ◽  
Organic Compounds ◽  
Photocatalytic Oxidation ◽  
Volatile Organic

scholarly journals Condensational uptake of semivolatile organic compounds in gasoline engine exhaust onto pre-existing inorganic particles

2011 ◽  
Vol 11 (1) ◽  
pp. 3461-3492
Author(s):  
S.-M. Li ◽  
J. Liggio ◽  
L. Graham ◽  
G. Lu ◽  
J. Brook ◽  
...  
Keyword(s):  
Air Quality ◽  
Gas Phase ◽  
Organic Compounds ◽  
Gasoline Engine ◽  
Particle Mass ◽  
Seed Particle ◽  
Dilution Ratio ◽  
Ambient Conditions ◽  
Engine Exhaust ◽  
Inorganic Particles

Abstract. This paper presents the results of laboratory studies on the condensational uptake of gaseous organic compounds in the exhaust of a light-duty gasoline engine onto preexisting sulfate and nitrate seed particles. Significant condensation of the gaseous organic compounds in the exhaust occurs onto pre-existing inorganic particles on a time scale of 2–5 min. The amount of condensed organic mass (COM) is proportional to the seed particle mass, suggesting that the uptake is due to dissolution, not adsorption. The solubility decreases as a power function with increased dilution of the exhaust, ranging from 0.23 g/g at a dilution ratio of 81, to 0.025 g/g at a dilution ratio of 2230. The solubility increases nonlinearly with increasing concentration of the total hydrocarbons in the gas phase (THC), rising from 0.12 g/g to 0.26 g/g for a CTHC increase of 1 to 18 μg m−3, suggesting that more organics are partitioned into the particles at higher gas phase concentrations. In terms of gas-particle partitioning, the condensational uptake of THC gases in gasoline engine exhaust can account for up to 30% of the total gas+particle THC. By incorporating the present findings, regional air quality modelling results suggest that the condensational uptake of THC onto sulfate particles alone can be comparable to the primary particle mass under moderately polluted ambient conditions. These findings are important for modelling and regulating the air quality impacts of gasoline vehicular emissions.

scholarly journals Emissions of organic carbon and methane from petroleum and dairy operations in California's San Joaquin Valley

2013 ◽  
Vol 13 (10) ◽  
pp. 28225-28278 ◽  
Author(s):  
D. R. Gentner ◽  
T. B. Ford ◽  
A. Guha ◽  
K. Boulanger ◽  
J. Brioude ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Organic Carbon ◽  
Gas Phase ◽  
Organic Compounds ◽  
Methane Emissions ◽  
San Joaquin Valley ◽  
Motor Vehicles ◽  
Meteorological Model ◽  
Wide Range ◽  
Petroleum Extraction

Abstract. Petroleum and dairy operations are prominent sources of gas-phase organic compounds in California's San Joaquin Valley. Ground site measurements in Bakersfield and aircraft measurements of reactive gas-phase organic compounds were made in this region as part of the CalNex (California Research at the Nexus of Air Quality and Climate Change) project to determine the sources contributing to regional gas-phase organic carbon emissions. Using a combination of near-source and downwind data, we assess the composition and magnitude of emissions from these prominent sources that are relatively understudied compared to motor vehicles We also developed a statistical modeling method with the FLEXPART-WRF transport and meteorological model using ground-based data to assess the spatial distribution of emissions in the San Joaquin Valley. We present evidence for large sources of paraffinic hydrocarbons from petroleum extraction/processing operations and oxygenated compounds from dairy (and other cattle) operations. In addition to the small straight-chain alkanes typically associated with petroleum operations, we observed a wide range of branched and cyclic alkanes that have limited previous in situ measurements or characterization in emissions from petroleum operations. Observed dairy emissions were dominated by ethanol, methanol, and acetic acid, and methane. Dairy operations were responsible for the vast majority of methane emissions in the San Joaquin Valley; observations of methane were well-correlated with non-vehicular ethanol, and multiple assessments of the spatial distribution of emissions in the San Joaquin Valley highlight the dominance of dairy operations for methane emissions. The good agreement of the observed petroleum operations source profile with the measured composition of non-methane hydrocarbons in unrefined natural gas associated with crude oil suggests a fugitive emissions pathway during petroleum extraction, storage, or processing with negligible coincident methane emissions Aircraft observations of emission hotspots from operations at oil wells and dairies are consistent with the statistical source footprint determined via transport modeling and ground-based data. At Bakersfield, petroleum and dairy operations each comprised 22–23% of anthropogenic non-methane organic carbon and were each responsible for ~12% of potential precursors to ozone, but their direct impacts as potential SOA precursors were estimated to be minor. A comparison with the California Air Resources Board emission inventory supports the current relative emission rates of reactive organic gases from these sources in the region.

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