Article pubs.acs.org/est
Evaporation Kinetics of Laboratory-Generated Secondary Organic Aerosols at Elevated Relative Humidity Jacqueline Wilson,† Dan Imre,‡ Josef Beránek,† Manish Shrivastava,† and Alla Zelenyuk*,† †
Pacific Northwest National Laboratory, Richland, Washington 99354, United States Imre Consulting, Richland, Washington 99352, United States
‡
S Supporting Information *
ABSTRACT: Secondary organic aerosols (SOA) dominate atmospheric organic aerosols that affect climate, air quality, and health. Recent studies indicate that, contrary to previously held assumptions, at low relative humidity (RH) these particles are semisolid and evaporate orders of magnitude slower than expected. Elevated relative humidity has the potential to affect significantly formation, properties, and atmospheric evolution of SOA particles. Here we present a study of the effect of RH on the room-temperature evaporation kinetics of SOA particles formed by ozonolysis of α-pinene and limonene. Experiments were carried out on α-pinene SOA particles generated, evaporated, and aged at 90% decreases the evaporated fraction. By comparison with the “dry-wet” experiment, the effect of forming and evaporating these SOA particles at RH >90%, in the “wet-wet” experiment, shown in Figure 3c, is very small. However, the evaporative mass loss of particles formed and
Figure 3. (a) The evaporation kinetics of size-selected α-pinene SOA particles formed at 90% RH and evaporated under dry conditions; (b) The evaporation kinetics of size-selected α-pinene SOA particles formed under dry conditions and evaporated at 90% RH; (c) The evaporation of α-pinene SOA particles formed and evaporated at 90% RH. The evaporation of the corresponding aged SOA particles is also shown in each figure.
aged at 90% RH, prior to evaporation (“wet-wet aged”), is significantly reduced compared to particles formed and aged under dry conditions (dry-wet aged). 246
DOI: 10.1021/es505331d Environ. Sci. Technol. 2015, 49, 243−249
Environmental Science & Technology
Article
Figure 4. (a) The evaporation kinetics of size-selected limonene SOA particles formed and evaporated under different RH conditions as indicated in the figure legend; (b) The comparison between evaporation kinetics of fresh and aged size-selected limonene SOA particles for “dry-dry” and “drywet” experiments.
viscosity solutions. Most notably, the results presented here show that this nearly size-independent evaporation persists even at RH > 90%, despite the fact that at this high RH SOA viscosity is significantly reduced.6,7 Overall, these evaporation studies conducted on laboratorygenerated SOA indicate that evaporation kinetics of α-pinene SOA at around 50% RH are almost the same as under dry conditions, although aging at 50% RH reduces the evaporating mass fraction. When evaporation of α-pinene SOA is carried out at RH >90%, the evaporating fraction increases slightly, however, aging these particles at this high RH significantly decreases the evaporating fraction. The evaporation of limonene SOA at low RH is very similar to α-pinene SOA. At higher RH evaporation increases somewhat, but aging at high RH significantly decreases evaporation. In all cases, evaporation kinetics is nearly size-independent, inconsistent with predicted evaporation kinetics for lowviscosity solution.4,23 As noted throughout the text, the SOA evaporation data presented in Figures 2-4 were used to derive effective volatility distributions that are presented in SI Table S1. In all cases, the effective volatility distributions calculated from SOA evaporation measurements are orders of magnitude lower than those derived from SOA formation studies, providing direct evidence for the importance of condensed-phase processes, for example, oligomer formation.23 As shown in SI Table S1, particle aging and especially particle aging at higher RH, leads to decrease in particle effective volatility. Finally, it is important to bear in mind that the evaporating mass fraction of ambient SOA is significantly lower than that of laboratory-generated pure SOA particles, with the slow evaporation phase being so slow that it is barely detectable.4 Our findings show that SOA volatility decreases due to particle aging, especially at higher RH, and due to the presence of hydrophobic organic gases, both of which, may explain the gap between the volatility of laboratory-generated pure SOA and that of ambient aerosol.
The data indicate that particle aging consistently reduces the evaporated mass fraction, however aging at very low RH changes the evaporating fraction by only 5−10%, irrespective of the RH during evaporation. In contrast, the evaporation of particles formed and aged at very high RH show larger differences with aging, where the evaporated fraction is reduced by 20−40%. The increase in VFR, or equivalently, fraction of low-volatility components (SI Table S1), with aging is consistent with previously observed increase in oligomer content (high molecular weight mass spectral peaks),4 particle hardening,8 and decrease in water uptake31 with particle aging. Simultaneous measurements of the mobility and vacuum aerodynamic diameters of limonene SOA particles formed by ozonolysis indicate that these particles are spherical22 and have a density of 1.23 ± 0.01 g cm−3, as compared to the limonene SOA estimated effective density of 1.3 ± 0.2 g cm−3.33 The results of the limonene evaporation studies are presented in Figure 4. Under dry conditions, little difference is seen between the evaporation of α-pinene and limonene SOA: limonene SOA particles (“dry-dry”) lose ∼50% of their volume after ∼2 h of evaporation and after ∼24 h VFR approaches 30%. Figure 4a shows that all fresh limonene SOA behaves in a similar way regardless of the RH present during formation and evaporation (“dry-dry”, “dry-wet”, “wet-dry”, and “wet-wet”). Some variation is seen−principally in the initial, fast evaporation phase−but after several hours, the VFRs are within 10%. Similar to α-pinene SOA, aging has the effect of reducing particle evaporative mass losses and increase in the fraction of particle’s low-volatility content (SI Table S1) over time. Figure 4b shows that aged limonene SOA particles (“dry-dry aged” and “dry-wet aged”) retain ∼20% more volume after 24 h of evaporation than fresh particles. Like α-pinene SOA, the evaporation of limonene SOA under all conditions is nearly size-independent. We find that the evaporation kinetics of SOA particles from two different precursors, under a wide range of RHs presented in Figures 2−4, exhibit nearly size-independent behavior irrespective of the RH during formation and/or evaporation. This is inconsistent with predicted evaporation kinetics for low247
DOI: 10.1021/es505331d Environ. Sci. Technol. 2015, 49, 243−249
Environmental Science & Technology
■
Article
(9) Zelenyuk, A.; Imre, D.; Beránek, J.; Abramson, E.; Wilson, J.; Shrivastava, M. Synergy between secondary organic aerosols and longrange transport of polycyclic aromatic hydrocarbons. Environ. Sci. Technol. 2012, 46 (22), 12459−12466. (10) Perraud, V.; Bruns, E. A.; Ezell, M. J.; Johnson, S. N.; Yu, Y.; Alexander, M. L.; Zelenyuk, A.; Imre, D.; Chang, W. L.; Dabdub, D.; Pankow, J. F.; Finlayson-Pitts, B. J. Nonequilibrium atmospheric secondary organic aerosol formation and growth. Proc. Natl. Acad. Sci. U. S. A. 2012, 109 (8), 2836−2841. (11) Cappa, C. D.; Wilson, K. R. Evolution of organic aerosol mass spectra upon heating: Implications for OA phase and partitioning behavior. Atmos. Chem. Phys. 2011, 11 (5), 1895−1911. (12) Loza, C. L.; Coggon, M. M.; Nguyen, T. B.; Zuend, A.; Flagan, R. C.; Seinfeld, J. H. On the mixing and evaporation of secondary organic aerosol components. Environ. Sci. Technol. 2013, 47 (12), 6173−6180. (13) Saukko, E.; Lambe, A. T.; Massoli, P.; Koop, T.; Wright, J. P.; Croasdale, D. R.; Pedernera, D. A.; Onasch, T. B.; Laaksonen, A.; Davidovits, P.; Worsnop, D. R.; Virtanen, A. Humidity-dependent phase state of SOA particles from biogenic and anthropogenic precursors. Atmos. Chem. Phys. 2012, 12 (16), 7517−7529. (14) Kidd, C.; Perraud, V.; Wingen, L. M.; Finlayson-Pitts, B. J. Integrating phase and composition of secondary organic aerosol from the ozonolysis of α-pinene. Proc. Natl. Acad. Sci. U. S. A. 2014, 16, 22706−22716. (15) Pierce, J. R.; Riipinen, I.; Kulmala, M.; Ehn, M.; Petaja, T.; Junninen, H.; Worsnop, D. R.; Donahue, N. M. Quantification of the volatility of secondary organic compounds in ultrafine particles during nucleation events. Atmos. Chem. Phys. 2011, 11 (17), 9019−9036. (16) Grieshop, A. P.; Donahue, N. M.; Robinson, A. L. Is the gasparticle partitioning in α-pinene secondary organic aerosol reversible? Geophys. Res. Lett. 2007, 34 (14), Artn L14810.. (17) Kalberer, M.; Paulsen, D.; Sax, M.; Steinbacher, M.; Dommen, J.; Prevot, A. S. H.; Fisseha, R.; Weingartner, E.; Frankevich, V.; Zenobi, R.; Baltensperger, U. Identification of polymers as major components of atmospheric organic aerosols. Science 2004, 303 (5664), 1659−1662. (18) Reynolds, J. C.; Last, D. J.; McGillen, M.; Nijs, A.; Horn, A. B.; Percival, C.; Carpenter, L. J.; Lewis, A. C. Structural analysis of oligomeric molecules formed from the reaction products of oleic acid ozonolysis. Environ. Sci. Technol. 2006, 40 (21), 6674−6681. (19) Yasmeen, F.; Vermeylen, R.; Szmigielski, R.; Iinuma, Y.; Boge, O.; Herrmann, H.; Maenhaut, W.; Claeys, M. Terpenylic acid and related compounds: Precursors for dimers in secondary organic aerosol from the ozonolysis of alpha- and beta-pinene. Atmos. Chem. Phys. 2010, 10 (19), 9383−9392. (20) Widmann, J. F.; Heusmann, C. M.; Davis, E. J. The effect of a polymeric additive on the evaporation of organic aerocolloidal droplets. Colloid Polym. Sci. 1998, 276 (3), 197−205. (21) Roth, C. M.; Goss, K. U.; Schwarzenbach, R. P. Sorption of a diverse set of organic vapors to urban aerosols. Environ. Sci. Technol. 2005, 39 (17), 6638−6643. (22) Zelenyuk, A.; Yang, J.; Song, C.; Zaveri, R. A.; Imre, D. A new real-time method for determining particles’ sphericity and density: Application to secondary organic aerosol formed by ozonolysis of αpinene. Environ. Sci. Technol. 2008, 42 (21), 8033−8038. (23) Shrivastava, M.; Zelenyuk, A.; Imre, D.; Easter, R.; Beranek, J.; Zaveri, R. A.; Fast, J. Implications of low volatility SOA and gas-phase fragmentation reactions on SOA loadings and their spatial and temporal evolution in the atmosphere. J. Geophys. Res.: Atmos. 2013, DOI: 10.1002/jgrd.50160. (24) Kristensen, K.; Cui, T.; Zhang, H.; Gold, A.; Glasius, M.; Surratt, J. D. Dimers in α-pinene secondary organic aerosol: Effect of hydroxyl radical, ozone, relative humidity and aerosol acidity. Atmos. Chem. Phys. 2014, 14 (8), 4201−4218. (25) Zelenyuk, A.; Imre, D. Beyond single particle mass spectrometry: Multidimensional characterisation of individual aerosol particles. Int. Rev. Phys. Chem. 2009, 28 (2), 309−358.
ASSOCIATED CONTENT
S Supporting Information *
Examples of the temporal evolutions of particle number concentrations in the evaporation chamber; effective volatility distributions derived from fitting the measured evaporation rate of SOA for all presented experimental conditions. This material is available free of charge via the Internet at http://pubs.acs. org/.
■
AUTHOR INFORMATION
Corresponding Author
*Phone: (509) 371-6155; fax: (509) 371-6139; e-mail: alla.
[email protected]. Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS This work was supported by the U.S. Department of Energy Office of Basic Energy Sciences, Chemical Sciences, Geosciences (A.Z. and J.B.), and Bioscience Division and Office of Biological and Environmental Research (Atmospheric Research Program) (J.W. and M.S.). This research was performed in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy’s Office of Biological and Environmental Research at Pacific Northwest National Laboratory.
■
REFERENCES
(1) Kanakidou, M.; Seinfeld, J. H.; Pandis, S. N.; Barnes, I.; Dentener, F. J.; Facchini, M. C.; Van Dingenen, R.; Ervens, B.; Nenes, A.; Nielsen, C. J.; Swietlicki, E.; Putaud, J. P.; Balkanski, Y.; Fuzzi, S.; Horth, J.; Moortgat, G. K.; Winterhalter, R.; Myhre, C. E. L.; Tsigaridis, K.; Vignati, E.; Stephanou, E. G.; Wilson, J. Organic aerosol and global climate modeling: A review. Atmos. Chem. Phys. 2005, 5, 1053−1123. (2) Volkamer, R.; Jimenez, J. L.; San Martini, F.; Dzepina, K.; Zhang, Q.; Salcedo, D.; Molina, L. T.; Worsnop, D. R.; Molina, M. J. Secondary organic aerosol formation from anthropogenic air pollution: Rapid and higher than expected. Geophys. Res. Lett. 2006, 33 (17), L17811. (3) Virtanen, A.; Joutsensaari, J.; Koop, T.; Kannosto, J.; Yli-Pirila, P.; Leskinen, J.; Makela, J. M.; Holopainen, J. K.; Poschl, U.; Kulmala, M.; Worsnop, D. R.; Laaksonen, A. An amorphous solid state of biogenic secondary organic aerosol particles. Nature 2010, 467 (7317), 824− 827. (4) Vaden, T. D.; Imre, D.; Beranek, J.; Shrivastava, M.; Zelenyuk, A. Evaporation kinetics and phase of laboratory and ambient secondary organic aerosol. Proc. Natl. Acad. Sci. U. S. A. 2011, 108 (6), 2190− 2195. (5) Vaden, T. D.; Song, C.; Zaveri, R. A.; Imre, D.; Zelenyuk, A. Morphology of mixed primary and secondary organic particles and the adsorption of spectator organic gases during aerosol formation. Proc. Natl. Acad. Sci. U. S. A. 2010, 107 (15), 6658−6663 invited. (6) Kuwata, M.; Martin, S. T. Phase of atmospheric secondary organic material affects its reactivity. Proc. Natl. Acad. Sci. U.S.A. 2012, 109 (43), 17354−17359. (7) Renbaum-Wolff, L.; Grayson, J. W.; Bateman, A. P.; Kuwata, M.; Sellier, M.; Murray, B. J.; Shilling, J. E.; Martin, S. T.; Bertram, A. K. Viscosity of α-pinene secondary organic material and implications for particle growth and reactivity. Proc. Natl. Acad. Sci. U. S. A. 2013, 110, 8014−8019. (8) Abramson, E.; Imre, D.; Beranek, J.; Wilson, J.; Zelenyuk, A. Experimental determination of chemical diffusion within secondary organic aerosol particles. Phys. Chem. Chem. Phys. 2013, 15 (8), 2983− 2991. 248
DOI: 10.1021/es505331d Environ. Sci. Technol. 2015, 49, 243−249
Environmental Science & Technology
Article
(26) Zelenyuk, A.; Yang, J.; Choi, E.; Imre, D.; SPLAT, I. I. An aircraft compatible, ultra-sensitive, high precision instrument for in-situ characterization of the size and composition of fine and ultrafine particles. Aerosol Sci. Technol. 2009, 43 (5), 411−424. (27) Zelenyuk, A.; Imre, D.; Cuadra-Rodriguez, L. A. Evaporation of water from particles in the aerodynamic lens inlet: An experimental study. Anal. Chem. 2006, 78 (19), 6942−6947. (28) Jonsson, Å. M.; Hallquist, M.; Ljungström, E. Impact of humidity on the ozone initiated oxidation of limonene, δ3-carene, and α-pinene. Environ. Sci. Technol. 2005, 40 (1), 188−194. (29) Ng, N. L.; Kroll, J. H.; Keywood, M. D.; Bahreini, R.; Varutbangkul, V.; Flagan, R. C.; Seinfeld, J. H.; Lee, A.; Goldstein, A. H. Contribution of first- versus second-generation products to secondary organic aerosols formed in the oxidation of biogenic hydrocarbons. Environ. Sci. Technol. 2006, 40 (7), 2283−2297. (30) Cocker, D. R.; Mader, B. T.; Kalberer, M.; Flagan, R. C.; Seinfeld, J. H. The effect of water on gas-particle partitioning of secondary organic aerosol: II. m-xylene and 1,3,5-trimethylbenzene photooxidation systems. Atmos. Environ. 2001, 35 (35), 6073−6085. (31) Varutbangkul, V.; Brechtel, F. J.; Bahreini, R.; Ng, N. L.; Keywood, M. D.; Kroll, J. H.; Flagan, R. C.; Seinfeld, J. H.; Lee, A.; Goldstein, A. H. Hygroscopicity of secondary organic aerosols formed by oxidation of cycloalkenes, monoterpenes, sesquiterpenes, and related compounds. Atmos. Chem. Phys. 2006, 6, 2367−2388. (32) Prenni, A. J.; Petters, M. D.; Kreidenweis, S. M.; DeMott, P. J.; Ziemann, P. J., Cloud droplet activation of secondary organic aerosol. J. Geophys. Res.: Atmos. 2007, 112, D10, Article Number: D10223, DOI: 10.1029/2006JD007963. (33) Saathoff, H.; Naumann, K. H.; Mohler, O.; Jonsson, A. M.; Hallquist, M.; Kiendler-Scharr, A.; Mentel, T. F.; Tillmann, R.; Schurath, U. Temperature dependence of yields of secondary organic aerosols from the ozonolysis of alpha-pinene and limonene. Atmos. Chem. Phys. 2009, 9 (5), 1551−1577.
249
DOI: 10.1021/es505331d Environ. Sci. Technol. 2015, 49, 243−249
