scholarly journals Technical Note: Vapor pressure estimation methods applied to secondary organic aerosol constituents from α-pinene oxidation: an intercomparison study

2010 ◽  
Vol 10 (13) ◽  
pp. 6271-6282 ◽  
Author(s):  
S. Compernolle ◽  
K. Ceulemans ◽  
J.-F. Müller
Keyword(s):  
Vapor Pressure ◽  
Functional Groups ◽  
State Of The Art ◽  
Organic Aerosol ◽  
Technical Note ◽  
Estimation Methods ◽  
Vapor Pressures ◽  
Aerosol Formation ◽  
Pressure Estimation ◽  
Intercomparison Study

Abstract. We applied and compared seven vapor pressure estimation methods to the condensable compounds generated in the oxidation of α-pinene, as described by the state-of-the-art mechanism of the BOREAM model Capouet et al., 2008. Several of these methods had to be extended in order to treat functional groups such as hydroperoxides and peroxy acyl nitrates. Large differences in the estimated vapor pressures are reported, which will inevitably lead to large differences in aerosol formation simulations. Cautioning remarks are given for some vapor pressure estimation methods.

scholarly journals Technical note: Vapor pressure estimation methods applied to secondary organic aerosol constituents from α-pinene oxidation: an intercomparison study

2010 ◽  
Vol 10 (4) ◽  
pp. 8487-8513 ◽  
Author(s):  
S. Compernolle ◽  
K. Ceulemans ◽  
J.-F. Müller
Keyword(s):  
Vapor Pressure ◽  
Functional Groups ◽  
State Of The Art ◽  
Organic Aerosol ◽  
Technical Note ◽  
Estimation Methods ◽  
Vapor Pressures ◽  
Aerosol Formation ◽  
Pressure Estimation ◽  
Intercomparison Study

Abstract. We applied and compared seven vapor pressure estimation methods to the condensable compounds generated in the oxidation of α-pinene, as described by the state-of-the-art mechanism of the BOREAM model (Capouet et al., 2008). Several of these methods had to be extended in order to treat functional groups such as hydroperoxides and peroxy acyl nitrates. Large differences in the estimated vapor pressures are reported, which will inevitably lead to large differences in aerosol formation simulations. Cautioning remarks are given for some vapor pressure estimation methods.

scholarly journals Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles at moderate relative humidity

2018 ◽  
Vol 18 (8) ◽  
pp. 5677-5689 ◽  
Author(s):  
Tengyu Liu ◽  
Dan Dan Huang ◽  
Zijun Li ◽  
Qianyun Liu ◽  
ManNin Chan ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Ammonium Sulfate ◽  
Functional Groups ◽  
Flow Reactor ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Seed Particles ◽  
The Difference ◽  
Wet Particles

Abstract. The formation of secondary organic aerosol (SOA) has been widely studied in the presence of dry seed particles at low relative humidity (RH). At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NOx under a range of OH exposures on initially wet or dry ammonium sulfate (AS) seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 1010 molecules cm−3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm−3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW) soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m ∕ z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS), indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory experiments conducted with a wide variety of SOA precursors and inorganic seeds under different NOx and RH conditions are warranted.

scholarly journals Novel methods for predicting gas–particle partitioning during the formation of secondary organic aerosol

2014 ◽  
Vol 14 (23) ◽  
pp. 13189-13204 ◽  
Author(s):  
F. Wania ◽  
Y. D. Lei ◽  
C. Wang ◽  
J. P. D. Abbatt ◽  
K.-U. Goss
Keyword(s):  
Functional Groups ◽  
Vapour Pressure ◽  
Secondary Organic Aerosol ◽  
Prediction Method ◽  
Organic Aerosol ◽  
Estimation Methods ◽  
Minor Effect ◽  
Normal Alkanes ◽  
Sorption Data ◽  
Order Of Magnitude

Abstract. Several methods have been presented in the literature to predict an organic chemical's equilibrium partitioning between the water insoluble organic matter (WIOM) component of aerosol and the gas phase, Ki,WIOM, as a function of temperature. They include (i) polyparameter linear free energy relationships calibrated with empirical aerosol sorption data, as well as (ii) the solvation models implemented in SPARC and (iii) the quantum-chemical software COSMOtherm, which predict solvation equilibria from molecular structure alone. We demonstrate that these methods can be used to predict Ki,WIOM for large numbers of individual molecules implicated in secondary organic aerosol (SOA) formation, including those with multiple functional groups. Although very different in their theoretical foundations, these methods give remarkably consistent results for the products of the reaction of normal alkanes with OH, i.e. their partition coefficients Ki,WIOM generally agree within one order of magnitude over a range of more than ten orders of magnitude. This level of agreement is much better than that achieved by different vapour pressure estimation methods that are more commonly used in the SOA community. Also, in contrast to the agreement between vapour pressure estimates, the agreement between the Ki,WIOM estimates does not deteriorate with increasing number of functional groups. Furthermore, these partitioning coefficients Ki,WIOM predicted SOA mass yields in agreement with those measured in chamber experiments of the oxidation of normal alkanes. If a Ki,WIOM prediction method was based on one or more surrogate molecules representing the solvation properties of the mixed OM phase of SOA, the choice of those molecule(s) was found to have a relatively minor effect on the predicted Ki,WIOM, as long as the molecule(s) are not very polar. This suggests that a single surrogate molecule, such as 1-octanol or a hypothetical SOA structure proposed by Kalberer et al. (2004), may often be sufficient to represent the WIOM component of the SOA phase, greatly simplifying the prediction. The presented methods could substitute for vapour-pressure-based methods in studies such as the explicit modelling of SOA formation from single precursor molecules in chamber experiments.

scholarly journals A reference data set for validating vapor pressure measurement techniques: homologous series of polyethylene glycols

2018 ◽  
Vol 11 (1) ◽  
pp. 49-63 ◽  
Author(s):  
Ulrich K. Krieger ◽  
Franziska Siegrist ◽  
Claudia Marcolli ◽  
Eva U. Emanuelsson ◽  
Freya M. Gøbel ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Quantum Chemistry ◽  
Homologous Series ◽  
Measurement Techniques ◽  
Estimation Methods ◽  
Polyethylene Glycols ◽  
Vapor Pressures ◽  
Data Set ◽  
Quantum Chemistry Calculations ◽  
Saturation Vapor

Abstract. To predict atmospheric partitioning of organic compounds between gas and aerosol particle phase based on explicit models for gas phase chemistry, saturation vapor pressures of the compounds need to be estimated. Estimation methods based on functional group contributions require training sets of compounds with well-established saturation vapor pressures. However, vapor pressures of semivolatile and low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique which is generally reported to be smaller than a factor of 2. At present, there is no general reference technique for measuring saturation vapor pressures of atmospherically relevant compounds with low vapor pressures at atmospheric temperatures. To address this problem, we measured vapor pressures with different techniques over a wide temperature range for intercomparison and to establish a reliable training set. We determined saturation vapor pressures for the homologous series of polyethylene glycols (H − (O − CH2 − CH2)n − OH) for n = 3 to n = 8 ranging in vapor pressure at 298 K from 10−7 to 5×10−2 Pa and compare them with quantum chemistry calculations. Such a homologous series provides a reference set that covers several orders of magnitude in saturation vapor pressure, allowing a critical assessment of the lower limits of detection of vapor pressures for the different techniques as well as permitting the identification of potential sources of systematic error. Also, internal consistency within the series allows outlying data to be rejected more easily. Most of the measured vapor pressures agreed within the stated uncertainty range. Deviations mostly occurred for vapor pressure values approaching the lower detection limit of a technique. The good agreement between the measurement techniques (some of which are sensitive to the mass accommodation coefficient and some not) suggests that the mass accommodation coefficients of the studied compounds are close to unity. The quantum chemistry calculations were about 1 order of magnitude higher than the measurements. We find that extrapolation of vapor pressures from elevated to atmospheric temperatures is permissible over a range of about 100 K for these compounds, suggesting that measurements should be performed best at temperatures yielding the highest-accuracy data, allowing subsequent extrapolation to atmospheric temperatures.

scholarly journals Fragmentation vs. functionalization: chemical aging and organic aerosol formation

2011 ◽  
Vol 11 (20) ◽  
pp. 10553-10563 ◽  
Author(s):  
H. J. Chacon-Madrid ◽  
N. M. Donahue
Keyword(s):  
Organic Aerosol ◽  
Transformation Process ◽  
Oxidation Products ◽  
Oxidation States ◽  
Oh Radical ◽  
Vapor Pressures ◽  
Aerosol Formation ◽  
Chemical Aging ◽  
Carbon Backbone ◽  
Insight Into

Abstract. The transformation process that a carbon backbone undergoes in the atmosphere is complex and dynamic. Understanding all these changes for all the species in detail is impractical; however, choosing different molecules that resemble progressively higher stages of oxidation or aging and studying them can give us an insight into general characteristics and mechanisms. Here we determine secondary organic aerosol (SOA) mass yields of two sequences of molecules reacting with the OH radical at high NOx. Each sequence consists of species with similar vapor pressures, but a succession of oxidation states. The first sequence consists of n-pentadecane, n-tridecanal, 2-, 7-tridecanone, and pinonaldehyde. The second sequence consists of n-nonadecane, n-heptadecanal and cis-pinonic acid. Oxidized molecules tend to have lower relative SOA mass yields; however, oxidation state alone was not enough to predict how efficiently a molecule forms SOA. Certain functionalities are able to fragment more easily than others, and even the position of these functionalities on a molecule can have an effect. n-Alkanes tend to have the highest yields, and n-aldehydes the lowest. n-Ketones have slightly higher yields when the ketone moiety is located on the side of the molecule and not in the center. In general, oxidation products remain efficient SOA sources, though fragmentation makes them less effective than comparable alkanes.

scholarly journals EVAPORATION: a new vapor pressure estimation method for organic molecules including non-additivity and intramolecular interactions

2011 ◽  
Vol 11 (4) ◽  
pp. 13229-13278
Author(s):  
S. Compernolle ◽  
K. Ceulemans ◽  
J.-F. Müller
Keyword(s):  
Molecular Structure ◽  
Vapor Pressure ◽  
Functional Groups ◽  
Vapour Pressure ◽  
Simple Formula ◽  
Organic Molecules ◽  
Intramolecular Interaction ◽  
Estimation Method ◽  
Organic Aerosol ◽  
Intramolecular Interactions

Abstract. We present EVAPORATION (Estimation of VApour Pressure of ORganics, Accounting for Temperature, Intramolecular, and Non-additivity effects), a method to predict vapour pressure p0 of organic molecules needing only molecular structure as input. The method is applicable to zero-, mono- and polyfunctional molecules. A simple formula to describe log10p0(T) is employed, that takes into account both a wide temperature dependence and the non-additivity of functional groups. In order to match the recent data on functionalised diacids an empirical modification to the method was introduced. Contributions due to carbon skeleton, functional groups, and intramolecular interaction between groups are included. Molecules typically originating from oxidation of biogenic molecules are within the scope of this method: carbonyls, alcohols, ethers, esters, nitrates, acids, peroxides, hydroperoxides, peroxy acyl nitrates and peracids. Therefore the method is especially suited to describe compounds forming secondary organic aerosol (SOA).

scholarly journals A reference data set for validating vapor pressure measurement techniques: Homologous series of polyethylene glycols

2017 ◽  
Author(s):  
Ulrich K. Krieger ◽  
Franziska Siegrist ◽  
Claudia Marcolli ◽  
Eva U. Emanuelsson ◽  
Freya M. Gøbel ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Quantum Chemistry ◽  
Homologous Series ◽  
Measurement Techniques ◽  
Estimation Methods ◽  
Polyethylene Glycols ◽  
Vapor Pressures ◽  
Data Set ◽  
Quantum Chemistry Calculations ◽  
Saturation Vapor

Abstract. To predict atmospheric partitioning of organic compounds between gas and aerosol particle phase based on explicit models for gas phase chemistry, saturation vapor pressures of the compounds need to be estimated. Estimation methods based on functional group contributions require training sets of compounds with well established saturation vapor pressures. However, vapor pressures of semi- and low volatile organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique which is generally reported to be smaller than a factor of two. At present, there is no general reference technique for measuring saturation vapor pressures of atmospherically relevant compounds with low vapor pressures at atmospheric temperatures. To address this problem we measured vapor pressures with different techniques over a wide temperature range for intercomparison and to establish a reliable training set. We determined saturation vapor pressures for the homologous series of polyethylene glycols (H–(O–CH2–CH2)n–OH) for n = 3 to n = 8 ranging in vapor pressure at 298 K from 10−7 Pa to 5 · 10−2 Pa and compare them with quantum chemistry calculations. Such a homologous series provides a reference set that covers several orders of magnitude in saturation vapor pressure, allowing a critical assessment of the lower limits of detection of vapor pressures for the different techniques as well as permitting the identification of potential sources of systematic error. Also, internal consistency within the series allows to reject outlying data more easily. Most of the measured vapor pressures agreed within the stated uncertainty range. Deviations mostly occurred for vapor pressures values approaching the lower detection limit of a technique. The good agreement between the measurement techniques (some of which are sensitive to the mass accommodation coefficient and some not) suggest that the mass accommodation coefficients of the studied compounds are close to unity. The quantum chemistry calculations were about one order of magnitude higher than the measurements. We find that extrapolation of vapor pressures from elevated to atmospheric temperatures is permissible over a range of about 100 K for these compounds, suggesting that measurements should be performed best at temperatures yielding the highest accuracy data allowing subsequent extrapolation to atmospheric temperatures.

scholarly journals Technical Note: Development of chemoinformatic tools to enumerate functional groups in molecules for organic aerosol characterization

2016 ◽  
Vol 16 (7) ◽  
pp. 4401-4422 ◽  
Author(s):  
Giulia Ruggeri ◽  
Satoshi Takahama
Keyword(s):  
Functional Groups ◽  
Chemical Speciation ◽  
Organic Aerosol ◽  
Technical Note ◽  
Carbon Oxidation ◽  
Estimation Model ◽  
Aerosol Composition ◽  
Reduced Representation ◽  
Complete Set ◽  
Chamber Studies

Abstract. Functional groups (FGs) can be used as a reduced representation of organic aerosol composition in both ambient and controlled chamber studies, as they retain a certain chemical specificity. Furthermore, FG composition has been informative for source apportionment, and various models based on a group contribution framework have been developed to calculate physicochemical properties of organic compounds. In this work, we provide a set of validated chemoinformatic patterns that correspond to (1) a complete set of functional groups that can entirely describe the molecules comprised in the α-pinene and 1,3,5-trimethylbenzene MCMv3.2 oxidation schemes, (2) FGs that are measurable by Fourier transform infrared spectroscopy (FTIR), (3) groups incorporated in the SIMPOL.1 vapor pressure estimation model, and (4) bonds necessary for the calculation of carbon oxidation state. We also provide example applications for this set of patterns. We compare available aerosol composition reported by chemical speciation measurements and FTIR for different emission sources, and calculate the FG contribution to the O : C ratio of simulated gas-phase composition generated from α-pinene photooxidation (using the MCMv3.2 oxidation scheme).

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