ACP Atmospheric Chemistry and Physics ACP Atmos. Chem. Phys. 1680-7324 Copernicus Publications Göttingen, Germany 10.5194/acp-12-2959-2012 Direct N<sub>2</sub>O<sub>5</sub> reactivity measurements at a polluted coastal site Riedel T. P. 1 2 Bertram T. H. 3 Ryder O. S. 3 Liu S. 4 Day D. A. 4 5 Russell L. M. 4 Gaston C. J. 4 Prather K. A. 3 4 Thornton J. A. 1 Department of Atmospheric Sciences, University of Washington, Seattle, USA Department of Chemistry, University of Washington, Seattle, USA Department of Chemistry and Biochemistry, University of California, San Diego, USA Scripps Institution of Oceanography, San Diego, USA Cooperative Institute for Research in the Environmental Sciences, University of Colorado, Boulder, USA 26 03 2012 12 6 2959 2968 Copyright: © 2012 T. P. Riedel et al. 2012 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://acp.copernicus.org/articles/12/2959/2012/acp-12-2959-2012.html The full text article is available as a PDF file from https://acp.copernicus.org/articles/12/2959/2012/acp-12-2959-2012.pdf

Direct measurements of N<sub>2</sub>O<sub>5</sub> reactivity on ambient aerosol particles were made during September 2009 at the Scripps Institution of Oceanography (SIO) Pier facility located in La Jolla, CA. N<sub>2</sub>O<sub>5</sub> reactivity measurements were made using a custom flow reactor and the particle modulation technique alongside measurements of aerosol particle size distributions and non-refractory composition. The pseudo-first order rate coefficients derived from the particle modulation technique and the particle surface area concentrations were used to determine the population average N<sub>2</sub>O<sub>5</sub> reaction probability, <i> γ</i>(N<sub>2</sub>O<sub>5</sub>), approximately every 50 min. Insufficient environmental controls within the instrumentation trailer led us to restrict our analysis primarily to nighttime measurements. Within this subset of data, <i> γ</i>(N<sub>2</sub>O<sub>5</sub>) ranged from <0.001 to 0.029 and showed significant day-to-day variations. We compare these data to a recent parameterization that utilizes aerosol composition measurements and an aerosol thermodynamics model. The parameterization captures several aspects of the measurements with similar general trends over the time series. However, the parameterization persistently overestimates the measurements by a factor of 1.5–3 and does not illustrate the same extent of variability. Assuming chloride is internally mixed across the particle population leads to the largest overestimates. Removing this assumption only partially reduces the discrepancies, suggesting that other particle characteristics that can suppress<i> γ</i>(N<sub>2</sub>O<sub>5</sub>) are important, such as organic coatings or non-aqueous particles. The largest apparent driver of day-to-day variability in the measured <i> γ</i>(N<sub>2</sub>O<sub>5</sub>) at this site was the particle nitrate loading, as inferred from both the measured particle composition and the parameterizations. The relative change in measured <i> γ</i>(N<sub>2</sub>O<sub>5</sub>) as a function of particle nitrate loading appears to be consistent with expectations based on laboratory data, providing direct support for the atmospheric importance of the so-called "nitrate effect".

 References Alexander, B., Hastings, M. G., Allman, D. J., Dachs, J., Thornton, J. A., and Kunasek, S. A.: Quantifying atmospheric nitrate formation pathways based on a global model of the oxygen isotopic composition (Δ<sup>17</sup>O) of atmospheric nitrate, Atmos. Chem. Phys., 9, 5043–5056, <a href="http://dx.doi.org/10.5194/acp-9-5043-2009">https://doi.org/10.5194/acp-9-5043-2009</a>, 2009. Baron, P. A. and Willeke, K.: Aerosol Measurement: Principles, Techniques, and Applications, 2 edn., Wiley-Interscience, New York, USA, 2001. Behnke, W., George, C., Scheer, V., and Zetzsch, C.: Production and decay of ClNO<sub>2</sub>, from the reaction of gaseous N<sub>2</sub>O<sub>5</sub> with NaCl solution: Bulk and aerosol experiments, J. Geophys. Res.-Atmos., 102, 3795–3804, <a href="http://dx.doi.org/10.1029/96jd03057">https://doi.org/10.1029/96jd03057</a>, 1997. Bertram, T. H. and Thornton, J. A.: Toward a general parameterization of N<sub>2</sub>O<sub>5</sub> reactivity on aqueous particles: the competing effects of particle liquid water, nitrate and chloride, Atmos. Chem. Phys., 9, 8351–8363, <a href="http://dx.doi.org/10.5194/acp-9-8351-2009">https://doi.org/10.5194/acp-9-8351-2009</a>, 2009. Bertram, T. H., Thornton, J. A., and Riedel, T. P.: An experimental technique for the direct measurement of N<sub>2</sub>O<sub>5</sub> reactivity on ambient particles, Atmos. Meas. Tech., 2, 231–242, <a href="http://dx.doi.org/10.5194/amt-2-231-2009">https://doi.org/10.5194/amt-2-231-2009</a>, 2009a. Bertram, T. H., Thornton, J. A., Riedel, T. P., Middlebrook, A. M., Bahreini, R., Bates, T. S., Quinn, P. K., and Coffman, D. J.: Direct observations of N<sub>2</sub>O<sub>5</sub> reactivity on ambient aerosol particles, Geophys. Res. Lett., 36, L19803, <a href="http://dx.doi.org/10.1029/2009gl040248">https://doi.org/10.1029/2009gl040248</a>, 2009b. Brown, S. S., Dibb, J. E., Stark, H., Aldener, M., Vozella, M., Whitlow, S., Williams, E. J., Lerner, B. M., Jakoubek, R., Middlebrook, A. M., DeGouw, J. A., Warneke, C., Goldan, P. D., Kuster, W. C., Angevine, W. M., Sueper, D. T., Quinn, P. K., Bates, T. S., Meagher, J. F., Fehsenfeld, F. C., and Ravishankara, A. R.: Nighttime removal of NO<sub>x</sub> in the summer marine boundary layer, Geophys. Res. Lett., 31, L07108, <a href="http://dx.doi.org/10.1029/2004gl019412">https://doi.org/10.1029/2004gl019412</a>, 2004. Brown, S. S., Ryerson, T. B., Wollny, A. G., Brock, C. A., Peltier, R., Sullivan, A. P., Weber, R. J., Dube, W. P., Trainer, M., Meagher, J. F., Fehsenfeld, F. C., and Ravishankara, A. R.: Variability in nocturnal nitrogen oxide processing and its role in regional air quality, Science, 311, 67–70, <a href="http://dx.doi.org/10.1126/science.1120120">https://doi.org/10.1126/science.1120120</a>, 2006. Brown, S. S., Dube, W. P., Fuchs, H., Ryerson, T. B., Wollny, A. G., Brock, C. A., Bahreini, R., Middlebrook, A. M., Neuman, J. A., Atlas, E., Roberts, J. M., Osthoff, H. D., Trainer, M., Fehsenfeld, F. C., and Ravishankara, A. R.: Reactive uptake coefficients for N<sub>2</sub>O<sub>5</sub> determined from aircraft measurements during the Second Texas Air Quality Study: Comparison to current model parameterizations, J. Geophys. Res.-Atmos., 114, D00F10, <a href="http://dx.doi.org/10.1029/2008jd011679">https://doi.org/10.1029/2008jd011679</a>, 2009. Cosman, L. M. and Bertram, A. K.: Reactive uptake of N<sub>2</sub>O<sub>5</sub> on aqueous H<sub>2</sub>SO<sub>4</sub> solutions coated with 1-component and 2-component monolayers, J. Phys. Chem. A, 112, 4625–4635, <a href="http://dx.doi.org/10.1021/jp8005469">https://doi.org/10.1021/jp8005469</a>, 2008. Cosman, L. M., Knopf, D. A., and Bertram, A. K.: N<sub>2</sub>O<sub>5</sub> reactive uptake on aqueous sulfuric acid solutions coated with branched and straight-chain insoluble organic surfactants, J. Phys. Chem. A, 112, 2386–2396, <a href="http://dx.doi.org/10.1021/jp710685r">https://doi.org/10.1021/jp710685r</a>, 2008. Davis, J. M., Bhave, P. V., and Foley, K. M.: Parameterization of N<sub>2</sub>O<sub>5</sub> reaction probabilities on the surface of particles containing ammonium, sulfate, and nitrate, Atmos. Chem. Phys., 8, 5295–5311, <a href="http://dx.doi.org/10.5194/acp-8-5295-2008">https://doi.org/10.5194/acp-8-5295-2008</a>, 2008. Dentener, F. J. and Crutzen, P. J.: Reaction of N<sub>2</sub>O<sub>5</sub> on tropospheric aerosols – Impacts on the global distributions of NO<sub>x</sub>, O<sub>3</sub>, AND OH, J. Geophys. Res.-Atmos., 98, 7149–7163, <a href="http://dx.doi.org/10.1029/92jd02979">https://doi.org/10.1029/92jd02979</a>, 1993. Engelhart, G. J., Hildebrandt, L., Kostenidou, E., Mihalopoulos, N., Donahue, N. M., and Pandis, S. N.: Water content of aged aerosol, Atmos. Chem. Phys., 11, 911–920, <a href="http://dx.doi.org/10.5194/acp-11-911-2011">https://doi.org/10.5194/acp-11-911-2011</a>, 2011. Finlayson-Pitts, B. J., Ezell, M. J., and Pitts, J. N.: Formation of chemically active chlorine compounds by reactions of atmospheric NaCl particles with gaseous N<sub>2</sub>O<sub>5</sub> and ClONO<sub>2</sub>, Nature, 337, 241–244, <a href="http://dx.doi.org/10.1038/337241a0">https://doi.org/10.1038/337241a0</a>, 1989. Folkers, M., Mentel, T. F., and Wahner, A.: Influence of an organic coating on the reactivity of aqueous aerosols probed by the heterogeneous hydrolysis of N<sub>2</sub>O<sub>5</sub>, Geophys. Res. Lett., 30, 1644, <a href="http://dx.doi.org/10.1029/2003gl017168">https://doi.org/10.1029/2003gl017168</a>, 2003. Hallquist, M., Stewart, D. J., Stephenson, S. K., and Cox, R. A.: Hydrolysis of N<sub>2</sub>O<sub>5</sub> on sub-micron sulfate aerosols, Phys. Chem. Chem. Phys., 5, 3453–3463, <a href="http://dx.doi.org/10.1039/b301827j">https://doi.org/10.1039/b301827j</a>, 2003. Hu, J. H. and Abbatt, J. P. D.: Reaction probabilities for N<sub>2</sub>O<sub>5</sub> hydrolysis on sulfuric acid and ammonium sulfate aerosols at room temperature, J. Phys. Chem. A, 101, 871–878, <a href="http://dx.doi.org/10.1021/jp9627436">https://doi.org/10.1021/jp9627436</a>, 1997. Jacob, D. J.: Heterogeneous chemistry and tropospheric ozone, Atmos. Environ., 34, 2131–2159, <a href="http://dx.doi.org/10.1016/s1352-2310(99)00462-8">https://doi.org/10.1016/s1352-2310(99)00462-8</a>, 2000. Kane, S. M., Caloz, F., and Leu, M. T.: Heterogeneous uptake of gaseous N<sub>2</sub>O<sub>5</sub> by (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>, NH<sub>4</sub>HSO<sub>4</sub>, and H<sub>2</sub>SO<sub>4</sub> aerosols, J. Phys. Chem. A, 105, 6465–6470, <a href="http://dx.doi.org/10.1021/jp010490x">https://doi.org/10.1021/jp010490x</a>, 2001. Kercher, J. P., Riedel, T. P., and Thornton, J. A.: Chlorine activation by N<sub>2</sub>O<sub>5</sub>: simultaneous, in situ detection of ClNO<sub>2</sub> and N<sub>2</sub>O<sub>5</sub> by chemical ionization mass spectrometry, Atmos. Meas. Tech., 2, 193–204, <a href="http://dx.doi.org/10.5194/amt-2-193-2009">https://doi.org/10.5194/amt-2-193-2009</a>, 2009. Liu, S., Day, D. A., Shields, J. E., and Russell, L. M.: Ozone-driven photochemical formation of carboxylic acid groups from alkane groups, Atmos. Chem. Phys. Discuss., 11, 7189–7233, <a href="http://dx.doi.org/10.5194/acpd-11-7189-2011">https://doi.org/10.5194/acpd-11-7189-2011</a>, 2011. Logan, J. A., Prather, M. J., Wofsy, S. C., and McElroy, M. B.: Tropospheric Chemistry – a global perspective, J. Geophys. Res.-Oc. Atmos., 86, 7210–7254, <a href="http://dx.doi.org/10.1029/JC086iC08p07210">https://doi.org/10.1029/JC086iC08p07210</a>, 1981. McNeill, V. F., Patterson, J., Wolfe, G. M., and Thornton, J. A.: The effect of varying levels of surfactant on the reactive uptake of N<sub>2</sub>O<sub>5</sub> to aqueous aerosol, Atmos. Chem. Phys., 6, 1635–1644, <a href="http://dx.doi.org/10.5194/acp-6-1635-2006">https://doi.org/10.5194/acp-6-1635-2006</a>, 2006. Mentel, T. F., Sohn, M., and Wahner, A.: Nitrate effect in the heterogeneous hydrolysis of dinitrogen pentoxide on aqueous aerosols, Phys. Chem. Chem. Phys., 1, 5451–5457, <a href="http://dx.doi.org/10.1039/a905338g">https://doi.org/10.1039/a905338g</a>, 1999. Mozurkewich, M. and Calvert, J. G.: Reaction probability of N<sub>2</sub>O<sub>5</sub> on aqueous aerosols, J. Geophys. Res.-Atmos., 93, 15889–15896, <a href="http://dx.doi.org/10.1029/JD093iD12p15889">https://doi.org/10.1029/JD093iD12p15889</a>, 1988. Ohara, T., Akimoto, H., Kurokawa, J., Horii, N., Yamaji, K., Yan, X., and Hayasaka, T.: An Asian emission inventory of anthropogenic emission sources for the period 1980–2020, Atmos. Chem. Phys., 7, 4419–4444, http://dx.doi.org/10.5194/acp-7-4419-2007https://doi.org/10.5194/acp-7-4419-2007, 2007. Osthoff, H. D., Roberts, J. M., Ravishankara, A. R., Williams, E. J., Lerner, B. M., Sommariva, R., Bates, T. S., Coffman, D., Quinn, P. K., Dibb, J. E., Stark, H., Burkholder, J. B., Talukdar, R. K., Meagher, J., Fehsenfeld, F. C., and Brown, S. S.: High levels of nitryl chloride in the polluted subtropical marine boundary layer, Nat. Geosci., 1, 324–328, <a href="http://dx.doi.org/10.1038/ngeo177">https://doi.org/10.1038/ngeo177</a>, 2008. Park, S.-C., Burden, D. K., and Nathanson, G. M.: The inhibition of N<sub>2</sub>O<sub>5</sub> hydrolysis in sulfuric acid by 1-butanol and 1-hexanol surfactant coatings, J. Phys. Chem. A, 111, 2921–2929, <a href="http://dx.doi.org/10.1021/jp068228h">https://doi.org/10.1021/jp068228h</a>, 2007. Roberts, J. M., Osthoff, H. D., Brown, S. S., Ravishankara, A. R., Coffman, D., Quinn, P., and Bates, T.: Laboratory studies of products of N<sub>2</sub>O<sub>5</sub> uptake on Cl<sup>-</sup> containing substrates, Geophys. Res. Lett., 36, L20808, <a href="http://dx.doi.org/10.1029/2009gl040448">https://doi.org/10.1029/2009gl040448</a>, 2009. Robinson, G. N., Worsnop, D. R., Jayne, J. T., Kolb, C. E., and Davidovits, P.: Heterogeneous uptake of ClONO<sub>2</sub> and N<sub>2</sub>O<sub>5</sub> by sulfuric acid solutions, J. Geophys. Res.-Atmos., 102, 3583–3601, <a href="http://dx.doi.org/10.1029/96jd03457">https://doi.org/10.1029/96jd03457</a>, 1997. Shindell, D. T., Faluvegi, G., Koch, D. M., Schmidt, G. A., Unger, N., and Bauer, S. E.: Improved Attribution of Climate Forcing to Emissions, Science, 326, 716–718, <a href="http://dx.doi.org/10.1126/science.1174760">https://doi.org/10.1126/science.1174760</a>, 2009. Thornton, J. A. and Abbatt, J. P. D.: N<sub>2</sub>O<sub>5</sub> reaction on submicron sea salt aerosol: Kinetics, products, and the effect of surface active organics, J. Phys. Chem. A, 109, 10004–10012, <a href="http://dx.doi.org/10.1021/jp054183t">https://doi.org/10.1021/jp054183t</a>, 2005. Thornton, J. A., Braban, C. F., and Abbatt, J. P. D.: N<sub>2</sub>O<sub>5</sub> hydrolysis on sub-micron organic aerosols: the effect of relative humidity, particle phase, and particle size, Phys. Chem. Chem. Phys., 5, 4593–4603, <a href="http://dx.doi.org/10.1039/b307498f">https://doi.org/10.1039/b307498f</a>, 2003. Thornton, J. A., Kercher, J. P., Riedel, T. P., Wagner, N. L., Cozic, J., Holloway, J. S., Dube, W. P., Wolfe, G. M., Quinn, P. K., Middlebrook, A. M., Alexander, B., and Brown, S. S.: A large atomic chlorine source inferred from mid-continental reactive nitrogen chemistry, Nature, 464, 271–274, <a href="http://dx.doi.org/10.1038/nature08905">https://doi.org/10.1038/nature08905</a>, 2010. Wahner, A., Mentel, T. F., Sohn, M., and Stier, J.: Heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> on sodium nitrate aerosol, J. Geophys. Res.-Atmos., 103, 31103–31112, <a href="http://dx.doi.org/10.1029/1998jd100022">https://doi.org/10.1029/1998jd100022</a>, 1998. Wexler, A. S. and Clegg, S. L.: Atmospheric aerosol models for systems including the ions H<sup>+</sup>, NH<sub>4</sub><sup>+</sup>, Na<sup>+</sup>, SO<sub>4</sub><sup>2-</sup>, NO<sub>3</sub><sup>-</sup>,Cl<sup>-</sup>, Br<sup>-</sup>, and H<sub>2</sub>O, J. Geophys. Res.-Atmos., 107, 4207, <a href="http://dx.doi.org/10.1029/2001jd000451">https://doi.org/10.1029/2001jd000451</a>, 2002. Yienger, J. J.: An evaluation of chemistry's role in the winter-spring ozone maximum found in the northern midlatitude free troposphere, J. Geophys. Res.-Atmos., 104, 8329–8329, <a href="http://dx.doi.org/10.1029/1999jd900140">https://doi.org/10.1029/1999jd900140</a>, 1999.