Abstract
Particle acidity affects aerosol concentrations, chemical composition, toxicity and nutrient bioavailability. We present a summary of thermodynamic analysis of comprehensive observations of ambient aerosol collected over the US and E.Mediterranean to understand the levels and drivers of aerosol pH. We find that acidic aerosol in the fine mode is ubiquitous, with levels that range between 0 and 2 throughout most of the data examined. The strong acidity is largely from the large difference in volatility between sulfate (the main acidic compound, which resides completely in the aerosol phase) and ammonia (the main neutralizing agent, which partitions between aerosol and gas-phase). This counterintuitive, but thermodynamically consistent finding explains why aerosol acidity in the southeastern United States has not decreased over the last decades, despite a 70% reduction in sulfates and a constant ammonia background. We then demonstrate that evaluation of model-predicted pH is critical for model predictions of semi-volatile species, e.g., nitrate.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Bougiatioti A, Nenes A, Paraskevopoulou D, Fourtziou L, Stavroulas I, Liakakou E, Myriokefalitakis S, Daskalakis N, Weber R, Gerasopoulos E, Nikolaou P, Mihalopoulos N (2017) The unappreciated effects of biomass burning on fine mode aerosol acidity, in review
Bougiatioti A, Nikolaou P, Stavroulas I, Kouvarakis G, Weber R, Nenes A, Kanakidou M, Mihalopoulos N (2016) Particle water and pH in the Eastern Mediterranean: Sources variability and implications for nutrients availability. Atmos Chem Phys 16:4579–4591. doi:10.5194/acp-16-4579-2016
Fountoukis C, Nenes A (2007) ISORROPIA II: a computationally efficient thermodynamic equilibrium model for K+-Ca2+-Mg2+-NH+ 4-Na+-SO4 2-NO3 --Cl--H2O aerosols. Atmos Chem Phys 7:4639–4659
Guo H, Xu L, Bougiatioti A, Cerully KM, Capps SL, Hite JR, Carlton AG, Lee SH, Bergin MH, Ng NL, Nenes A, Weber RJ (2015) Fine-particle water and pH in the southeastern United States. Atmos Chem Phys 15:5211–5228. doi:10.5194/acp-15-5211-2015
Guo H, Sullivan AP, Campuzano-Jost P, Schroder JC, Lopez-Hilfiker FD, Dibb JE, Jimenez JL, Thornton JA, Brown SS, Nenes A, Weber RJ (2016) Fine particle pH and the partitioning of nitric acid during winter in the northeastern United States. J Geophys Res Atmos 121(10):355–310, 376. doi:10.1002/2016jd025311
Guo H, Liu J, Froyd KD, Roberts JM, Veres PR, Hayes PL, Jimenez JL, Nenes A, Weber RJ (2017) Fine particle pH and gas-particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign, in review
Hennigan CJ, Izumi J, Sullivan AP, Weber RJ, Nenes A (2015) A critical evaluation of proxy methods used to estimate the acidity of atmospheric particles. Atmos Chem Phys 15:2775–2790. doi:10.5194/acp-15-2775-2015
Meskhidze N, Chameides W, Nenes A, Chen G (2003) Iron mobilization in mineral dust: can anthropogenic SO2 emissions affect ocean productivity? Geophys Res Lett 30(21):2085. doi:10.1029/2003GL018035
Vasilakos P, Russell A, Nenes A (2017) Aerosol pH and its effect on nitrate over a decade (2001–2011) in the United States, in preparation
Weber RJ, Guo H, Russell AG, Nenes A (2016) High aerosol acidity despite declining atmospheric sulfate concentrations over the past 15 years. Nat Geosci 9:282–285. doi:10.1038/ngeo2665
Xu L, Middlebrook AM, Liao J, de Gouw JA, Guo H, Weber RJ, Nenes A, Lopez-Hilfiker FD, Lee BH, Thornton JA, Brock CA, Neuman JA, Nowak JB, Pollack IB, Welti A, Graus M, Warneke C, Ng NL (2016) Enhanced formation of isoprene-derived organic aerosol in sulfur-rich power plant plumes during Southeast Nexus. J Geophys Res Atmos 121(11):137–111, 153. doi:10.1002/2016jd025156
Acknowledgements
This work was supported by the Electric Power Research Institute, Phillips 66 Company, the US NSF grants AGS-0931492 and AGS-0802237, the European Union (European Social Fund—ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF)—Research Funding Program ARISTEIA I—PANOPLY, US EPA STAR grant R835410, and NOAA CPO Award NA10OAR4310102.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2018 Springer International Publishing AG
About this paper
Cite this paper
Nenes, A. et al. (2018). High Aerosol Acidity Despite Declining Atmospheric Sulfate Concentrations: Lessons from Observations and Implications for Models. In: Mensink, C., Kallos, G. (eds) Air Pollution Modeling and its Application XXV. ITM 2016. Springer Proceedings in Complexity. Springer, Cham. https://doi.org/10.1007/978-3-319-57645-9_27
Download citation
DOI: https://doi.org/10.1007/978-3-319-57645-9_27
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-57644-2
Online ISBN: 978-3-319-57645-9
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)