Effect of Bulk Composition on the Heterogeneous Oxidation of Semi-Solid Atmospheric Aerosols
"> Figure 1
<p>Schematic of the flow reactor used for particle collection and offline gas chromatography coupled to mass spectrometry (GC-MS) analysis. Saccharide particles were generated by a constant output atomizer and mixed with flows of humidified N<sub>2</sub>, O<sub>2</sub>, O<sub>3</sub>, and dry N<sub>2</sub>. A total of a 3.0 L min<sup>−1</sup> aerosol stream entered the atmospheric pressure flow tube to react with OH radicals. Hexane was injected from the bottom 1/5 of the flow tube. Upon exiting the flow tube, the OH concentration was measured by quantifying the loss of hexane tracer using gas chromatograph with flame ionization detection (GC-FID). The aerosol stream was analyzed by a scanning mobility particle sizer (SMPS) and collected by a Teflon filter.</p> "> Figure 2
<p>Surface-weighted particle size distribution for unreacted equimolar saccharide particles. The mean surface-weighted diameter and the total concentration of number particle size were 218.2 nm and 3.05 × 10<sup>5</sup> cm<sup>−3</sup> for the VUV-AMS analysis sample (black, dashed line) and 366.4 nm and 2.58 × 10<sup>5</sup> cm<sup>−3</sup> for the GC-MS analysis sample (red, dashed line).</p> "> Figure 3
<p>VUV-AMS spectrum of unreacted equimolar MGP–lactose aerosols recorded at 10.5 eV photoionization energy. The m/z 60, m/z 73, m/z 121, m/z 144, and m/z 163 were monitored during the kinetic measurements.</p> "> Figure 4
<p>Relative abundance of the MGP reactant as a function of OH exposure in particles with MGP:lactose molar ratios of 1:1 (red, solid circles), 2:1 (black, solid squares), 4:1 (blue, solid triangles), and 8:1 (green, solid diamonds) at RH = 30%. Online analyses were performed using VUV-AMS. Also displayed is the MGP decay for MGP particles at RH = 30% (purple open triangles) [<a href="#B16-atmosphere-10-00791" class="html-bibr">16</a>]. The error bars are 2σ of the mean values. The solid lines are exponential fits to the data for OH exposures below 2 × 10<sup>12</sup> cm<sup>−3</sup> s and extrapolated to higher values (dashed lines).</p> "> Figure 5
<p>Modeled (solid line) and experimental (markers) fractions of unreacted MGP remaining in the particle as a function of OH exposure for MGP:lactose molar ratios of 1:1 (red), 2:1 (black), 4:1 (blue), and 8:1 (green).</p> "> Figure 6
<p>GC-MS chromatogram of silylated reacted (upper panel) and unreacted (lower panel) particles for an MGP:lactose molar ratio of 2:1 at 0.7 × 10<sup>12</sup> cm<sup>−3</sup> s OH exposure. The retention time for the internal standard xylose was 6.17 min and 6.83 min, 9.13 min for MGP, 12.79 min and 13.10 min for lactose, and 10.09 min for glucose. All the saccharides were identified with authentic samples.</p> "> Figure 7
<p>Relative abundance of unreacted MGP (open circles) and lactose (filed squares) in semi-solid MGP–lactose particles at 30% RH as a function of OH exposure for MGP:lactose molar ratios of (<b>a</b>) 1:1 (red markers); (<b>b</b>) 2:1 (black markers); (<b>c</b>) 4:1 (blue markers). The offline analyses were performed using GC-MS. The error bars represent the maximum and minimum experimental values. The lines were modeled MGP (solid lines) and lactose (dashed lines) profiles using the parameters displayed in <a href="#atmosphere-10-00791-t001" class="html-table">Table 1</a>.</p> "> Figure 8
<p>Logarithm of the particle viscosity calculated using the Stock–Einstein equation for MGP:lactose molar ratios of (<b>a</b>) 1:1; (<b>b</b>) 2:1; and (<b>c</b>) 4:1 at a constant OH gas number density of 1.08 × 10<sup>10</sup> cm<sup>−3</sup>, corresponding to total OH exposure of 5 × 10<sup>11</sup> cm<sup>−3</sup> s. The top panels display the viscosity gradient near the particle surface.</p> ">
Abstract
:1. Introduction
2. Experiments
3. Modeling of the Particle Composition
4. Results and Discussion
4.1. VUV-AMS Analysis
4.2. GC-MS Analysis
5. Relevance for Atmospheric Chemistry
6. Conclusions
Supplementary Materials
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
- Shiraiwa, M.; Li, Y.; Tsimpidi, A.P.; Karydis, V.A.; Berkemeier, T.; Pandis, S.N.; Lelieveld, J.; Koop, T.; Pöschl, U. Global distribution of particle phase state in atmospheric secondary organic aerosols. Nat. Commun. 2017, 8, 15002. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Baustian, K.J.; Wise, M.E.; Jensen, E.J.; Schill, G.P.; Freedman, M.A.; Tolbert, M.A. State transformations and ice nucleation in amorphous (semi-)solid organic aerosol. Atmos. Chem. Phys. 2013, 13, 5615–5628. [Google Scholar] [CrossRef] [Green Version]
- Kalberer, M.; Paulsen, D.; Sax, M.; Steinbacher, M.; Dommen, J.; Prevot, A.S.H.; Fisseha, R.; Weingartner, E.; Frankevich, V.; Zenobi, R.; et al. Identification of Polymers as Major Components of Atmospheric Organic Aerosols. Science 2004, 303, 1659–1662. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Russell, L.M.; Bahadur, R.; Ziemann, P.J. Identifying organic aerosol sources by comparing functional group composition in chamber and atmospheric particles. Proc. Nati. Acad. Sci. USA 2011, 108, 3516–3521. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Virtanen, A.; Joutsensaari, J.; Koop, T.; Kannosto, J.; Yli-Pirilä, P.; Leskinen, J.; Mäkelä, J.M.; Holopainen, J.K.; Pöschl, U.; Kulmala, M.; et al. An amorphous solid state of biogenic secondary organic aerosol particles. Nature 2010, 467, 824–827. [Google Scholar] [CrossRef] [PubMed]
- Saukko, E.; Lambe, A.; Massoli, P.; Koop, T.P.; Wright, J.R.; Croasdale, D.; Pedernera, D.B.; Onasch, T.; Laaksonen, A.; Davidovits, P.; et al. Humidity-dependent phase state of SOA particles from biogenic and anthropogenic precursors. Atmos. Chem. Phys. 2012, 12, 4447–4476. [Google Scholar] [CrossRef]
- Hand, J.L.; Malm, W.C.; Laskin, A.; Day, D.; Lee, T.; Wang, C.; Carrico, C.; Carrillo, J.; Cowin, J.P.; Collett, J., Jr.; et al. Optical, physical, and chemical properties of tar balls observed during the Yosemite Aerosol Characterization Study. J. Geophys. Res. 2005, 110, D21210. [Google Scholar] [CrossRef]
- Pósfai, M.; Gelencsér, A.; Simonics, R.; Arató, K.; Li, J.; Hobbs, P.V.; Buseck, P.R. Atmospheric tar balls: Particles from biomass and biofuel burning. J. Geophys. Res. 2004, 109, D06213. [Google Scholar] [CrossRef] [Green Version]
- Reid, J.P.; Bertram, A.K.; Topping, D.O.; Laskin, A.; Martin, S.T.; Petters, M.D.; Pope, F.D.; Rovelli, G. The viscosity of atmospherically relevant organic particles. Nat. Commun. 2018, 9, 956. [Google Scholar] [CrossRef] [Green Version]
- Mikhailov, E.; Vlasenko, S.; Martin, S.T.; Koop, T.; Pöschl, U. Amorphous and crystalline aerosol particles interacting with water vapor: Conceptual framework and experimental evidence for restructuring, phase transitions and kinetic limitations. Atmos. Chem. Phys. 2009, 9, 9491–9522. [Google Scholar] [CrossRef] [Green Version]
- Browne, E.C.; Zhang, X.L.; Franklin, J.P.; Ridley, K.J.; Kirchstetter, T.W.; Wilson, K.R.; Cappa, C.D.; Kroll, J.H. Effect of heterogeneous oxidative aging on light absorption by biomass burning organic aerosol. Aerosol Sci. Technol. 2019, 53, 663–674. [Google Scholar] [CrossRef]
- Shi, X.J.; Zhang, W.T.; Liu, J.J. Comparison of Anthropogenic Aerosol Climate Effects among Three Climate Models with Reduced Complexity. Atmosphere 2019, 10, 456. [Google Scholar] [CrossRef] [Green Version]
- Kang, J.Y.; Bae, S.Y.; Park, R.S.; Han, J.Y. Aerosol Indirect Effects on the Predicted Precipitation in a Global Weather Forecasting Model. Atmosphere 2019, 10, 392. [Google Scholar] [CrossRef] [Green Version]
- Liu, P.F.; Li, Y.J.; Wang, Y.; Bateman, A.P.; Zhang, Y.; Gong, Z.H.; Bertram, A.K.; Martin, S.T. Highly Viscous States Affect the Browning of Atmospheric Organic Particulate Matter. ACS Cent. Sci. 2018, 4, 207–215. [Google Scholar] [CrossRef] [Green Version]
- Shiraiwa, M.; Ammann, M.; Koop, T.; Pöschl, U. Gas uptake and chemical aging of semisolid organic aerosol particles. Proc. Nati. Acad. Sci. USA 2011, 108, 11003–11008. [Google Scholar] [CrossRef] [Green Version]
- Fan, H.; Tinsley, M.R.; Goulay, F. Effect of Relative Humidity on the OH-Initiated Heterogeneous Oxidation of Monosaccharide Nanoparticles. J. Phys. Chem. A 2015, 119, 11182–11190. [Google Scholar] [CrossRef]
- Laskin, A.; Gilles, M.K.; Knopf, D.A.; Wang, B.; China, S. Progress in the Analysis of Complex Atmospheric Particles. Annu. Rev. Anal. Chem. 2016, 9, 117–143. [Google Scholar] [CrossRef] [Green Version]
- Slade, J.H.; Knopf, D.A. Multiphase OH oxidation kinetics of organic aerosol: The role of particle phase state and relative humidity. Geophys. Res. Lett. 2014, 41, 5297–5306. [Google Scholar] [CrossRef]
- Davies, J.F.; Wilson, K.R. Nanoscale interfacial gradients formed by the reactive uptake of OH radicals onto viscous aerosol surfaces. Chem. Sci. 2015, 6, 7020–7027. [Google Scholar] [CrossRef] [Green Version]
- Steimer, S.S.; Berkemeier, T.; Gilgen, A.; Krieger, U.K.; Peter, T.; Shiraiwa, M.; Ammann, M. Shikimic acid ozonolysis kinetics of the transition from liquid aqueous solution to highly viscous glass. Phys. Chem. Chem. Phys. 2015, 17, 31101–31109. [Google Scholar] [CrossRef] [Green Version]
- Chim, M.M.; Chow, C.Y.; Davies, J.F.; Chan, M.N. Effects of Relative Humidity and Particle Phase Water on the Heterogeneous OH Oxidation of 2-Methylglutaric Acid Aqueous Droplets. J. Phys. Chem. A 2017, 121, 1666–1674. [Google Scholar] [CrossRef]
- Marshall, F.H.; Miles, R.E.H.; Song, Y.-C.; Ohm, P.B.; Power, R.M.; Reid, J.P.; Dutcher, C.S. Diffusion and reactivity in ultraviscous aerosol and the correlation with particle viscosity. Chem. Sci. 2016, 7, 1298–1308. [Google Scholar] [CrossRef] [Green Version]
- Katrib, Y.; Biskos, G.; Buseck, P.R.; Davidovits, P.; Jayne, J.T.; Mochida, M.; Wise, M.E.; Worsnop, D.R.; Martin, S.T. Ozonolysis of Mixed Oleic-Acid/Stearic-Acid Particles: Reaction Kinetics and Chemical Morphology. J. Phys. Chem. A 2005, 109, 10910–10919. [Google Scholar] [CrossRef] [PubMed]
- Hearn, J.D.; Smith, G.D. Ozonolysis of Mixed Oleic Acid/n-Docosane Particles: The Roles of Phase, Morphology, and Metastable States. J. Phys. Chem. A 2007, 111, 11059–11065. [Google Scholar] [CrossRef] [PubMed]
- Mendez, M.; Visez, N.; Gosselin, S.; Crenn, V.; Riffault, V.; Petitprez, D. Reactive and Nonreactive Ozone Uptake during Aging of Oleic Acid Particles. J. Phys. Chem. A 2014, 118, 9471–9481. [Google Scholar] [CrossRef] [PubMed]
- Wang, M.; Yao, L.; Zheng, J.; Wang, X.; Chen, J.; Yang, X.; Worsnop, D.R.; Donahue, N.M.; Wang, L. Reactions of Atmospheric Particulate Stabilized Criegee Intermediates Lead to High-Molecular-Weight Aerosol Components. Environ. Sci. Technol. 2016, 50, 5702–5710. [Google Scholar] [CrossRef]
- Jacobs, M.I.; Xu, B.; Kostko, O.; Wiegel, A.A.; Houle, F.A.; Ahmed, M.; Wilson, K.R. Using Nanoparticle X-ray Spectroscopy to Probe the Formation of Reactive Chemical Gradients in Diffusion-Limited Aerosols. J. Phys. Chem. A 2019, 123, 6034–6044. [Google Scholar] [CrossRef] [Green Version]
- Wiegel, A.A.; Liu, M.J.; Hinsberg, W.D.; Wilson, K.R.; Houle, F.A. Diffusive confinement of free radical intermediates in the OH radical oxidation of semisolid aerosols. Phys. Chem. Chem. Phys. 2017, 19, 6814–6830. [Google Scholar] [CrossRef] [Green Version]
- Wiegel, A.A.; Wilson, K.R.; Hinsberg, W.D.; Houle, F.A. Stochastic methods for aerosol chemistry: A compact molecular description of functionalization and fragmentation in the heterogeneous oxidation of squalane aerosol by OH radicals. Phys. Chem. Chem. Phys. 2015, 17, 4398–4411. [Google Scholar] [CrossRef] [Green Version]
- Power, R.M.; Simpson, S.H.; Reid, J.P.; Hudson, A.J. The transition from liquid to solid-like behaviour in ultrahigh viscosity aerosol particles. Chem. Sci. 2013, 4, 2597–2604. [Google Scholar] [CrossRef]
- Price, H.C.; Murray, B.J.; Mattsson, J.; O’Sullivan, D.; Wilson, T.W.; Baustian, K.J.; Benning, L.G. Quantifying water diffusion in high-viscosity and glassy aqueous solutions using a Raman isotope tracer method. Atmosph. Chem. Phys. 2014, 14, 3817–3830. [Google Scholar] [CrossRef] [Green Version]
- Eyoy, E.; Maclean, A.M.; Royelli, G.; Li, Y.; Tsimpidi, A.P.; Karydis, V.A.; Kamal, S.; Lelieveld, J.; Shiraiwa, M.; Reid, J.P.; et al. Predictions of diffusion rates of large organic molecules in secondary organic aerosols using the Stokes-Einstein and fractional Stokes-Einstein relations. Atmos. Chem. Phys. 2019, 19, 10073–10085. [Google Scholar] [CrossRef] [Green Version]
- Price, H.C.; Mattsson, J.; Murray, B.J. Sucrose diffusion in aqueous solution. Phys. Chem. Chem. Phys. 2016, 18, 19207–19216. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- O’Meara, S.; Topping, D.O.; Zaveri, R.A.; McFiggans, G. An efficient approach for treating composition-dependent diffusion within organic particles. Atmos. Chem. Phys. 2017, 17, 10477–10494. [Google Scholar] [CrossRef] [Green Version]
- Fowler, K.; Connolly, P.J.; Topping, D.O.; O’Meara, S. Maxwell-Stefan diffusion: A framework for predicting condensed phase diffusion and phase separation in atmospheric aerosol. Atmos. Chem. Phys. 2018, 18, 1629–1642. [Google Scholar] [CrossRef] [Green Version]
- Burkholder, J.B.; Abbate, J.P.D.; Barnes, I.; Roberts, J.M.; Melamed, M.L.; Ammann, M.; Bertram, A.K.; Cappa, C.D.; Carlton, A.G.; Carpenter, L.J.; et al. The Essential Role for Laboratory Studies in Atmospheric Chemistry. Environ. Sci. Technol. 2017, 51, 2519–2528. [Google Scholar] [CrossRef] [Green Version]
- Houle, F.A.; Hinsberg, W.D.; Wilson, K.R. Oxidation of a model alkane aerosol by OH radical: The emergent nature of reactive uptake. Phys. Chem. Chem. Phys. 2015, 17, 4412–4423. [Google Scholar] [CrossRef] [Green Version]
- Nah, T.; Kessler, S.H.; Daumit, K.E.; Kroll, J.H.; Leone, S.R.; Wilson, K.R. Influence of Molecular Structure and Chemical Functionality on the Heterogeneous OH-Initiated Oxidation of Unsaturated Organic Particles. J. Phys. Chem. A 2014, 118, 4106–4119. [Google Scholar] [CrossRef] [Green Version]
- Kolesar, K.R.; Buffaloe, G.; Wilson, K.R.; Cappa, C.D. OH-Initiated Heterogeneous Oxidation of Internally-Mixed Squalane and Secondary Organic Aerosol. Environ. Sci. Technol. 2014, 48, 3196–3202. [Google Scholar] [CrossRef] [Green Version]
- Arangio, A.M.; Slade, J.H.; Berkemeier, T.; Poeschl, U.; Knopf, D.A.; Shiraiwa, M. Multiphase Chemical Kinetics of OH Radical Uptake by Molecular Organic Markers of Biomass Burning Aerosols: Humidity and Temperature Dependence, Surface Reaction, and Bulk Diffusion. J. Phys. Chem. A 2015, 119, 4533–4544. [Google Scholar] [CrossRef] [Green Version]
- Lu, J.W.; Rickards, A.M.J.; Walker, J.S.; Knox, K.J.; Miles, R.E.H.; Reid, J.P.; Signorell, R. Timescales of water transport in viscous aerosol: Measurements on sub-micron particles and dependence on conditioning history. Phys. Chem. Chem. Phys. 2014, 16, 9819–9830. [Google Scholar] [CrossRef] [PubMed]
- Lai, C.Y.; Liu, Y.C.; Ma, J.Z.; Ma, Q.X.; He, H. Degradation kinetics of levoglucosan initiated by hydroxyl radical under different environmental conditions. Atmos. Environ. 2014, 91, 32–39. [Google Scholar] [CrossRef]
- Tong, H.-J.; Reid, J.P.; Bones, D.L.; Luo, B.P.; Krieger, U.K. Measurements of the timescales for the mass transfer of water in glassy aerosol at low relative humidity and ambient temperature. Atmos. Chem. Phys. 2011, 11, 4739–4754. [Google Scholar] [CrossRef] [Green Version]
- Zobrist, B.; Soonsin, V.; Luo, B.P.; Krieger, U.K.; Marcolli, C.; Peter, T.; Koop, T. Ultra-slow water diffusion in aqueous sucrose glasses. Phys. Chem. Chem. Phys. 2011, 13, 3514–3526. [Google Scholar] [CrossRef] [PubMed]
- Houle, F.A.; Wiegel, A.A.; Wilson, K.R. Predicting Aerosol Reactivity Across Scales: From the Laboratory to the Atmosphere. Environ. Sci. Technol. 2018, 52, 13774–13781. [Google Scholar] [CrossRef]
- Fan, H.; Wenyika Masaya, T.; Goulay, F. Effect of surface–bulk partitioning on the heterogeneous oxidation of aqueous saccharide aerosols. Phys. Chem. Chem. Phys. 2019, 21, 2992–3001. [Google Scholar] [CrossRef]
- Song, Y.C.; Haddrell, A.E.; Bzdek, B.R.; Reid, J.P.; Bannan, T.; Topping, D.O.; Percival, C.; Cai, C. Measurements and Predictions of Binary Component Aerosol Particle Viscosity. J. Phys. Chem. A 2016, 120, 8123–8137. [Google Scholar] [CrossRef] [Green Version]
- Mysak, E.R.; Wilson, K.R.; Jimenez-Cruz, M.; Ahmed, M.; Baer, T. Synchrotron radiation based aerosol time-of-flight mass spectrometry for organic constituents. Anal. Chem. 2005, 77, 5953–5960. [Google Scholar] [CrossRef]
- Smith, J.D.; Kroll, J.H.; Cappa, C.D.; Che, D.L.; Liu, C.L.; Ahmed, M.; Leone, S.R.; Worsnop, D.R.; Wilson, K.R. The heterogeneous reaction of hydroxyl radicals with sub-micron squalane particles: A model system for understanding the oxidative aging of ambient aerosols. Atmos. Chem. Phys. 2009, 9, 3209–3222. [Google Scholar] [CrossRef] [Green Version]
- Atkinson, R. Kinetics of the gas-phase reactions of OH radicals with alkanes and cycloalkanes. Atmosph. Chem. Phys. 2003, 3, 2233–2307. [Google Scholar] [CrossRef] [Green Version]
- Atkinson, R. Kinetics and mechanistics of the gas-phase reactions of the hydroxyl radical with organic-compounds under atmospheric conditions. Chem. Rev. 1986, 86, 69–201. [Google Scholar] [CrossRef]
- Hearn, J.D.; Smith, G.D. A mixed-phase relative rates technique for measuring aerosol reaction kinetics. Geophys. Res. Lett. 2006, 33, L17805. [Google Scholar] [CrossRef]
- Vieceli, J.R.M.; Potter, N.; Dang, L.X.; Garrett, B.C.; Tobias, D.J. Molecular Dynamics Simulations of Atmospheric Oxidants at the Air−Water Interface: Solvation and Accommodation of OH and O3. J. Phys. Chem. B 2005, 15876–15892. [Google Scholar] [CrossRef] [PubMed]
- Bucknall, T.; Edwards, H.E.; Kemsley, K.G.; Moore, J.S.; Phillips, G.O. The formation of malonaldehyde in irradiated carbohydrates. Carbohydr. Res. 1978, 62, 49–59. [Google Scholar] [CrossRef]
- Zakatova, N.V.; Minkhadzhiddinova, D.P.; Sharpatyi, V.A. Role of OH-radicals in the radiolytic decomposition of carbohydrates and polysaccharides. Russ. Chem. Bull. 1969. [Google Scholar] [CrossRef]
- Davies, J.F.; Wilson, K.R. Raman Spectroscopy of Isotopic Water Diffusion in Ultraviscous, Glassy, and Gel States in Aerosol by Use of Optical Tweezers. Anal. Chem. 2016, 88, 2361–2366. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Vignes, A. Diffusion in Binary Solutions. Variation of Diffusion Coefficient with Composition. Ind. Eng. Chem. Fundam. 1966, 5, 189–199. [Google Scholar] [CrossRef]
- Lide, D.R. CRC Handbook of Chemistry and Physics, 64th ed.; CRC Press: Boca Raton, FL, USA, 1983. [Google Scholar]
- Mai, H.; Shiraiwa, M.; Flagan, R.C.; Seinfeld, J.H. Under What Conditions Can Equilibrium Gas–Particle Partitioning Be Expected to Hold in the Atmosphere? Environ. Sci. Technol. 2015, 49, 11485–11491. [Google Scholar] [CrossRef] [Green Version]
- Yli-Juuti, T.; Pajunoja, A.; Tikkanen, O.P.; Buchholz, A.; Faiola, C.; Vaisanen, O.; Hao, L.Q.; Kari, E.; Perakyla, O.; Garmash, O.; et al. Factors controlling the evaporation of secondary organic aerosol from alpha-pinene ozonolysis. Geophys. Res. Lett. 2017, 44, 2562–2570. [Google Scholar] [CrossRef]
Parameter | Value | Description |
---|---|---|
RH | 30% | Relative humidity |
(OH) | 1.35 × 1011 cm−3 (VUV-AMS) 8.70 × 1010 cm−3 (GC-MS) | OH average experimental number density 1 |
100 nm (VUV-AMS) 180 nm (GC-MS) | Particle radius | |
10 s−1 | Pseudo first-order adsorption rate for OH [28] | |
2.86 × 1010 s−1 | OH desorption rate coefficient [53] | |
5.31 × 10−12 cm3 s−1 | OH + MGP rate coefficient in aqueous solutions [55] | |
5.15 × 10−12 cm3 s−1 | OH + lactose rate coefficient in aqueous solutions [54] | |
1 × 109 cm2 s−1 | OH diffusion coefficient [56] | |
6.0 × 10−13 cm2 s−1 | MGP diffusion coefficient at RH = 30% (35 times the value obtained based on the S–E: logη = 5.554 [47]) 2 | |
1.5 × 10−17 cm2 s−1 | Lactose diffusion coefficient at RH = 30% (from S–E equation: logη = 8.526 [47]) 2 |
Molar Ratio (MGP:lactose) | Rate Constant kMGP ± 2σ (cm3 s−1) | Uptake Coefficient (γMGP ± 2σ) |
---|---|---|
1:1 | 4.02 ± 4.78 × 10−14 | 0.05 ± 0.06 |
2:1 | 2.24 ± 1.10 × 10−13 | 0.27 ± 0.15 |
4:1 | 3.26 ± 0.04 × 10−13 | 0.38 ± 0.01 |
8:1 | 4.73 ± 0.68 × 10−13 | 0.53 ± 0.10 |
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Share and Cite
Fan, H.; Goulay, F. Effect of Bulk Composition on the Heterogeneous Oxidation of Semi-Solid Atmospheric Aerosols. Atmosphere 2019, 10, 791. https://doi.org/10.3390/atmos10120791
Fan H, Goulay F. Effect of Bulk Composition on the Heterogeneous Oxidation of Semi-Solid Atmospheric Aerosols. Atmosphere. 2019; 10(12):791. https://doi.org/10.3390/atmos10120791
Chicago/Turabian StyleFan, Hanyu, and Fabien Goulay. 2019. "Effect of Bulk Composition on the Heterogeneous Oxidation of Semi-Solid Atmospheric Aerosols" Atmosphere 10, no. 12: 791. https://doi.org/10.3390/atmos10120791