scholarly journals Multiphase OH oxidation kinetics of organic aerosol: The role of particle phase state and relative humidity

2014 ◽  
Vol 41 (14) ◽  
pp. 5297-5306 ◽  
Author(s):  
Jonathan H. Slade ◽  
Daniel A. Knopf
Keyword(s):  
Relative Humidity ◽  
Oxidation Kinetics ◽  
Phase State ◽  
Organic Aerosol ◽  
Particle Phase ◽  
Kinetics Of

scholarly journals Cloud droplet activation through oxidation of organic aerosol influenced by temperature and particle phase state

2017 ◽  
Vol 44 (3) ◽  
pp. 1583-1591 ◽  
Author(s):  
Jonathan H. Slade ◽  
Manabu Shiraiwa ◽  
Andrea Arangio ◽  
Hang Su ◽  
Ulrich Pöschl ◽  
...  
Keyword(s):  
Phase State ◽  
Cloud Droplet ◽  
Organic Aerosol ◽  
Particle Phase ◽  
Droplet Activation

scholarly journals Examining the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol formation during the 2013 Southern Oxidant and Aerosol Study (SOAS) at the Look Rock, Tennessee ground site

2015 ◽  
Vol 15 (15) ◽  
pp. 8871-8888 ◽  
Author(s):  
S. H. Budisulistiorini ◽  
X. Li ◽  
S. T. Bairai ◽  
J. Renfro ◽  
Y. Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Anthropogenic Emissions ◽  
Strongly Correlated ◽  
Particle Phase ◽  
Aerosol Formation ◽  
Aerosol Acidity ◽  
Southeastern Us

Abstract. A suite of offline and real-time gas- and particle-phase measurements was deployed at Look Rock, Tennessee (TN), during the 2013 Southern Oxidant and Aerosol Study (SOAS) to examine the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol (SOA) formation. High- and low-time-resolution PM2.5 samples were collected for analysis of known tracer compounds in isoprene-derived SOA by gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) and ultra performance liquid chromatography/diode array detection-electrospray ionization-high-resolution quadrupole time-of-flight mass spectrometry (UPLC/DAD-ESI-HR-QTOFMS). Source apportionment of the organic aerosol (OA) was determined by positive matrix factorization (PMF) analysis of mass spectrometric data acquired on an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). Campaign average mass concentrations of the sum of quantified isoprene-derived SOA tracers contributed to ~ 9 % (up to 28 %) of the total OA mass, with isoprene-epoxydiol (IEPOX) chemistry accounting for ~ 97 % of the quantified tracers. PMF analysis resolved a factor with a profile similar to the IEPOX-OA factor resolved in an Atlanta study and was therefore designated IEPOX-OA. This factor was strongly correlated (r2 > 0.7) with 2-methyltetrols, C5-alkene triols, IEPOX-derived organosulfates, and dimers of organosulfates, confirming the role of IEPOX chemistry as the source. On average, IEPOX-derived SOA tracer mass was ~ 26 % (up to 49 %) of the IEPOX-OA factor mass, which accounted for 32 % of the total OA. A low-volatility oxygenated organic aerosol (LV-OOA) and an oxidized factor with a profile similar to 91Fac observed in areas where emissions are biogenic-dominated were also resolved by PMF analysis, whereas no primary organic aerosol (POA) sources could be resolved. These findings were consistent with low levels of primary pollutants, such as nitric oxide (NO ~ 0.03 ppb), carbon monoxide (CO ~ 116 ppb), and black carbon (BC ~ 0.2 μg m−3). Particle-phase sulfate is fairly correlated (r2 ~ 0.3) with both methacrylic acid epoxide (MAE)/hydroxymethyl-methyl-α-lactone (HMML)- (henceforth called methacrolein (MACR)-derived SOA tracers) and IEPOX-derived SOA tracers, and more strongly correlated (r2 ~ 0.6) with the IEPOX-OA factor, in sum suggesting an important role of sulfate in isoprene SOA formation. Moderate correlation between the MACR-derived SOA tracer 2-methylglyceric acid with sum of reactive and reservoir nitrogen oxides (NOy; r2 = 0.38) and nitrate (r2 = 0.45) indicates the potential influence of anthropogenic emissions through long-range transport. Despite the lack of a clear association of IEPOX-OA with locally estimated aerosol acidity and liquid water content (LWC), box model calculations of IEPOX uptake using the simpleGAMMA model, accounting for the role of acidity and aerosol water, predicted the abundance of the IEPOX-derived SOA tracers 2-methyltetrols and the corresponding sulfates with good accuracy (r2 ~ 0.5 and ~ 0.7, respectively). The modeling and data combined suggest an anthropogenic influence on isoprene-derived SOA formation through acid-catalyzed heterogeneous chemistry of IEPOX in the southeastern US. However, it appears that this process was not limited by aerosol acidity or LWC at Look Rock during SOAS. Future studies should further explore the extent to which acidity and LWC as well as aerosol viscosity and morphology becomes a limiting factor of IEPOX-derived SOA, and their modulation by anthropogenic emissions.

scholarly journals The oxidation kinetics of depleted uranium and its low-alloy molybdenum alloys in moist air

2019 ◽  
Vol 63 (3) ◽  
pp. 100-104
Author(s):  
T. Chmela ◽  
P. Krupička
Keyword(s):  
Relative Humidity ◽  
Reaction Kinetics ◽  
Oxidation Kinetics ◽  
Reaction Rate ◽  
Depleted Uranium ◽  
Rate Equations ◽  
Moist Air ◽  
Molybdenum Alloys ◽  
Exponential Behaviour ◽  
Kinetics Of

Abstract The oxidation kinetics of depleted uranium and its low-alloy molybdenum alloys (U-2wt.%Mo, U-5wt.%Mo) were measured in a moist air (75% relative humidity) at 60 and 75 ° C. Coefficients of reaction rate equations were determined for linear oxidation kinetics. In the oxidation of depleted uranium at 75 ° C, a change in reaction kinetics from linear to exponential behaviour was observed after about 2500 hours.

scholarly journals Examining the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol formation during the 2013 Southern Oxidant and Aerosol Study (SOAS) at the Look Rock, Tennessee, ground site

2015 ◽  
Vol 15 (5) ◽  
pp. 7365-7417 ◽  
Author(s):  
S. H. Budisulistiorini ◽  
X. Li ◽  
S. T. Bairai ◽  
J. Renfro ◽  
Y. Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Anthropogenic Emissions ◽  
Strongly Correlated ◽  
Particle Phase ◽  
Aerosol Formation ◽  
Aerosol Acidity ◽  
Southeastern Us

Abstract. A suite of offline and real-time gas- and particle-phase measurements was deployed at Look Rock, Tennessee (TN), during the 2013 Southern Oxidant and Aerosol Study (SOAS) to examine the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol (SOA) formation. High- and low-time resolution PM2.5 samples were collected for analysis of known tracer compounds in isoprene-derived SOA by gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) and ultra performance liquid chromatography/diode array detection-electrospray ionization-high-resolution quadrupole time-of-flight mass spectrometry (UPLC/DAD-ESI-HR-QTOFMS). Source apportionment of the organic aerosol (OA) was determined by positive matrix factorization (PMF) analysis of mass spectrometric data acquired on an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). Campaign average mass concentrations of the sum of quantified isoprene-derived SOA tracers contributed to ~9% (up to 26%) of the total OA mass, with isoprene-epoxydiol (IEPOX) chemistry accounting for ~97% of the quantified tracers. PMF analysis resolved a factor with a profile similar to the IEPOX-OA factor resolved in an Atlanta study and was therefore designated IEPOX-OA. This factor was strongly correlated (r2>0.7) with 2-methyltetrols, C5-alkene triols, IEPOX-derived organosulfates, and dimers of organosulfates, confirming the role of IEPOX chemistry as the source. On average, IEPOX-derived SOA tracer mass was ~25% (up to 47%) of the IEPOX-OA factor mass, which accounted for 32% of the total OA. A low-volatility oxygenated organic aerosol (LV-OOA) and an oxidized factor with a profile similar to 91Fac observed in areas where emissions are biogenic-dominated were also resolved by PMF analysis, whereas no primary organic aerosol (POA) sources could be resolved. These findings were consistent with low levels of primary pollutants, such as nitric oxide (NO~0.03ppb), carbon monoxide (CO~116 ppb), and black carbon (BC~0.2 μg m−3). Particle-phase sulfate is fairly correlated (r2~0.3) with both MAE- and IEPOX-derived SOA tracers, and more strongly correlated (r2~0.6) with the IEPOX-OA factor, in sum suggesting an important role of sulfate in isoprene SOA formation. Moderate correlation between the methacrylic acid epoxide (MAE)-derived SOA tracer 2-methylglyceric acid with sum of reactive and reservoir nitrogen oxides (NOy; r2=0.38) and nitrate (r2=0.45) indicates the potential influence of anthropogenic emissions through long-range transport. Despite the lack of a~clear association of IEPOX-OA with locally estimated aerosol acidity and liquid water content (LWC), box model calculations of IEPOX uptake using the simpleGAMMA model, accounting for the role of acidity and aerosol water, predicted the abundance of the IEPOX-derived SOA tracers 2-methyltetrols and the corresponding sulfates with good accuracy (r2~0.5 and ~0.7, respectively). The modeling and data combined suggest an anthropogenic influence on isoprene-derived SOA formation through acid-catalyzed heterogeneous chemistry of IEPOX in the southeastern US. However, it appears that this process was not limited by aerosol acidity or LWC at Look Rock during SOAS. Future studies should further explore the extent to which acidity and LWC becomes a limiting factor of IEPOX-derived SOA, and their modulation by anthropogenic emissions.

Indoor aerosol water content and phase state in U.S. residences: impacts of relative humidity, aerosol mass and composition, and mechanical system operation

2020 ◽  
Vol 22 (10) ◽  
pp. 2031-2057
Author(s):  
Bryan E. Cummings ◽  
Ying Li ◽  
Peter F. DeCarlo ◽  
Manabu Shiraiwa ◽  
Michael S. Waring
Keyword(s):  
Particulate Matter ◽  
Relative Humidity ◽  
Water Content ◽  
Mechanical System ◽  
Phase State ◽  
Organic Aerosol ◽  
System Operation ◽  
Aerosol Mass ◽  
Inorganic Aerosol ◽  
Indoor Aerosol

Hygroscopic particulate matter constituents promote uptake of aerosol water, depending on relative humidity, which can constrain qualities such as organic aerosol phase state and inorganic aerosol deliquescence and efflorescence.

scholarly journals Kinetic modeling of secondary organic aerosol formation: effects of particle- and gas-phase reactions of semivolatile products

2007 ◽  
Vol 7 (15) ◽  
pp. 4135-4147 ◽  
Author(s):  
A. W. H. Chan ◽  
J. H. Kroll ◽  
N. L. Ng ◽  
J. H. Seinfeld
Keyword(s):  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Laboratory Data ◽  
Organic Aerosol ◽  
Formation Mechanisms ◽  
Hydrocarbon Oxidation ◽  
Phase Reaction ◽  
Particle Phase ◽  
Aerosol Formation ◽  
Kinetics Of

Abstract. The distinguishing mechanism of formation of secondary organic aerosol (SOA) is the partitioning of semivolatile hydrocarbon oxidation products between the gas and aerosol phases. While SOA formation is typically described in terms of partitioning only, the rate of formation and ultimate yield of SOA can also depend on the kinetics of both gas- and aerosol-phase processes. We present a general equilibrium/kinetic model of SOA formation that provides a framework for evaluating the extent to which the controlling mechanisms of SOA formation can be inferred from laboratory chamber data. With this model we examine the effect on SOA formation of gas-phase oxidation of first-generation products to either more or less volatile species, of particle-phase reaction (both first- and second-order kinetics), of the rate of parent hydrocarbon oxidation, and of the extent of reaction of the parent hydrocarbon. The effect of pre-existing organic aerosol mass on SOA yield, an issue of direct relevance to the translation of laboratory data to atmospheric applications, is examined. The importance of direct chemical measurements of gas- and particle-phase species is underscored in identifying SOA formation mechanisms.

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