References

ACP

Atmospheric Chemistry and Physics

ACP

Atmos. Chem. Phys.

1680-7324

Copernicus Publications

Göttingen, Germany

10.5194/acp-11-11415-2011

Mass-spectrometric identification of primary biological particle markers and application to pristine submicron aerosol measurements in Amazonia

Schneider

¹ Freutel

¹ Zorn

S. R.

¹ ² Chen

² Farmer

D. K.

³ Jimenez

J. L.

³ Martin

S. T.

² Artaxo

⁴ Wiedensohler

⁵ Borrmann

¹ ⁶

Particle Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany

School of Engineering and Applied Sciences and Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA

Dept. of Chem. & Biochem. & CIRES, University of Colorado, Boulder, CO, USA

Applied Physics Department, Institute of Physics, University of São Paulo, Brazil

Leibniz Institute for Tropospheric Research, Leipzig, Germany

Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, Germany

17 11 2011

11 22 11415 11429

2011

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/11/11415/2011/acp-11-11415-2011.html

The full text article is available as a PDF file from https://acp.copernicus.org/articles/11/11415/2011/acp-11-11415-2011.pdf

The detection of primary biological material in submicron aerosol by means of thermal desorption/electron impact ionization aerosol mass spectrometry was investigated. Mass spectra of amino acids, carbohydrates, small peptides, and proteins, all of which are key building blocks of biological particles, were recorded in laboratory experiments. Several characteristic marker fragments were identified. The intensity of the marker signals relative to the total organic mass spectrum allows for an estimation of the content of primary biological material in ambient organic aerosol. The developed method was applied to mass spectra recorded during AMAZE-08, a field campaign conducted in the pristine rainforest of the central Amazon Basin, Brazil, during the wet season of February and March 2008. The low abundance of identified marker fragments places upper limits of 7.5% for amino acids and 5.6% for carbohydrates on the contribution of primary biological aerosol particles (PBAP) to the submicron organic aerosol mass concentration during this time period. Upper limits for the absolute submicron concentrations for both compound classes range from 0.01 to 0.1 μg m<sup>−3</sup>. Carbohydrates and proteins (composed of amino acids) make up for about two thirds of the dry mass of a biological cell. Thus, our findings suggest an upper limit for the PBAP mass fraction of about 20% to the submicron organic aerosol measured in Amazonia during AMAZE-08.

References 1

Aiken, A. C., Salcedo, D., Cubison, M. J., Huffman, J. A., DeCarlo, P. F., Ulbrich, I. M., Docherty, K. S., Sueper, D., Kimmel, J. R., Worsnop, D. R., Trimborn, A., Northway, M., Stone, E. A., Schauer, J. J., Volkamer, R. M., Fortner, E., de Foy, B., Wang, J., Laskin, A., Shutthanandan, V., Zheng, J., Zhang, R., Gaffney, J., Marley, N. A., Paredes-Miranda, G., Arnott, W. P., Molina, L. T., Sosa, G., and Jimenez, J. L.: Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) – Part 1: Fine particle composition and organic source apportionment, Atmos. Chem. Phys., 9, 6633–6653, <a href="http://dx.doi.org/10.5194/acp-9-6633-2009">https://doi.org/10.5194/acp-9-6633-2009</a>, 2009.

Alfarra, M. R., Prévôt, A. S. H., Szidat, S., Sandradewi, J., Weimer, S., Lanz, V. A., Schreiber, D., Mohr, M., and Baltensperger, U.: Identification of the mass spectral signature of organic aerosols from wood burning emissions, Environ. Sci. Technol., 41, 5770–5777, <a href="http://dx.doi.org/10.1021/es062289b">https://doi.org/10.1021/es062289b</a>, 2007.

Allan, J. D., Delia, A. E., Coe, H., Bower, K. N., Alfarra, M. R., Jimenez, J. L., Middlebrook, A. M., Drewnick, F., Onasch, T. B., Canagaratna, M. R., Jayne, J. T., and Worsnop, D. R.: A generalised method for the extraction of chemically resolved mass spectra from aerodyne aerosol mass spectrometer data, J. Aerosol. Sci., 35, 909–922, 2004.

Beyer, H. and Walter, W.: Lehrbuch der organischen Chemie, Hirzel, Stuttgart, 1988.

Campos, M. G. R., Bogdanov, S., de Almeida-Muradian, L. B., Szczesna, T., Mancebo, Y., Frigerio, C., and Ferreira, F.: Pollen composition and standardisation of analytical methods, Journal of Apicultural Research, 47, 154–161, 2008.

Canagaratna, M. R., Jayne, J. T., Jimenez, J. L., Allan, J. D., Alfarra, M. R., Zhang, Q., Onasch, T. B., Drewnick, F., Coe, H., Middlebrook, A., Delia, A., Williams, L. R., Trimborn, A. M., Northway, M. J., DeCarlo, P. F., Kolb, C. E., Davidovits, P., and Worsnop, D. R.: Chemical and microphysical characterization of ambient aerosols with the aerodyne aerosol mass spectrometer, Mass Spectrom. Rev., 26, 185–222, 2007.

Chen, Q.: Formation of biogenic secondary organic aerosol, Ph.D. thesis, Harvard University, 2011.

Chen, Q., Farmer, D. K., Schneider, J., Zorn, S. R., Heald, C. L., Karl, T. G., Guenther, A., Allan, J. D., Robinson, N., Coe, H., Kimmel, J. R., Pauliquevis, T., Borrmann, S., Pöschl, U., Andreae, M. O., Artaxo, P., Jimenez, J. L., and Martin, S. T.: Mass spectral characterization of submicron biogenic organic particles in the Amazon Basin, Geophys. Res. Lett., 36, L20806, <a href="http://dx.doi.org/10.1029/2009gl039880">https://doi.org/10.1029/2009gl039880</a>, 2009.

Cubison, M. J., Ortega, A. M., Hayes, P. L., Farmer, D. K., Day, D., Lechner, M. J., Brune, W. H., Apel, E., Diskin, G. S., Fisher, J. A., Fuelberg, H. E., Hecobian, A., Knapp, D. J., Mikoviny, T., Riemer, D., Sachse, G. W., Sessions, W., Weber, R. J., Weinheimer, A. J., Wisthaler, A., and Jimenez, J. L.: Effects of aging on organic aerosol from open biomass burning smoke in aircraft and lab studies, Atmos. Chem. Phys. Discuss., 11, 12103–12140, <a href="http://dx.doi.org/10.5194/acpd-11-12103-2011">https://doi.org/10.5194/acpd-11-12103-2011</a>, 2011.

Czerwieniec, G. A., Russell, S. C., Tobias, H. J., Pitesky, M. E., Fergenson, D. P., Steele, P., Srivastava, A., Horn, J. M., Frank, M., Gard, E. E., and Lebrilla, C. B.: Stable isotope labeling of entire Bacillus atrophaeus spores and vegetative cells using bioaerosol mass spectrometry, Anal. Chem., 77, 1081–1087, <a href="http://dx.doi.org/10.1021/Ac0488098">https://doi.org/10.1021/Ac0488098</a>, 2005.

DeCarlo, P. F., Kimmel, J. R., Trimborn, A., Northway, M. J., Jayne, J. T., Aiken, A. C., Gonin, M., Fuhrer, K., Horvath, T., Docherty, K. S., Worsnop, D. R., and Jimenez, J. L.: Field-deployable, high-resolution, time-of-flight aerosol mass spectrometer, Anal. Chem., 78, 8281–8289, 2006.

Deguillaume, L., Leriche, M., Amato, P., Ariya, P. A., Delort, A.-M., Pöschl, U., Chaumerliac, N., Bauer, H., Flossmann, A. I., and Morris, C. E.: Microbiology and atmospheric processes: chemical interactions of primary biological aerosols, Biogeosciences, 5, 1073–1084, <a href="http://dx.doi.org/10.5194/bg-5-1073-2008">https://doi.org/10.5194/bg-5-1073-2008</a>, 2008.

Diehl, K., Quick, C., Matthias-Maser, S., Mitra, S. K., and Jaenicke, R.: The ice nucleating ability of pollen – Part I: Laboratory studies in deposition and condensation freezing modes, Atmos. Res., 58, 75–87, 2001.

Diehl, K., Matthias-Maser, S., Jaenicke, R., and Mitra, S. K.: The ice nucleating ability of pollen: Part II. Laboratory studies in immersion and contact freezing modes, Atmos. Res., 61, 125–133, 2002.

Diesch, J. M.: Untersuchung des Verdampfungs- und Ionisationsprozesses im Aerodyne Aerosol Massenspektrometer, Diploma Thesis, University Mainz, 2008.

Drewnick, F., Hings, S. S., DeCarlo, P., Jayne, J. T., Gonin, M., Fuhrer, K., Weimer, S., Jimenez, J. L., Demerjian, K. L., Borrmann, S., and Worsnop, D. R.: A new time-of-flight aerosol mass spectrometer (TOF-AMS) – Instrument description and first field deployment, Aerosol Sci. Technol., 39, 637–658, 2005.

Duplissy, J., DeCarlo, P. F., Dommen, J., Alfarra, M. R., Metzger, A., Barmpadimos, I., Prévôt, A. S. H., Weingartner, E., Tritscher, T., Gysel, M., Aiken, A. C., Jimenez, J. L., Canagaratna, M. R., Worsnop, D. R., Collins, D. R., Tomlinson, J., and Baltensperger, U.: Relating hygroscopicity and composition of organic aerosol particulate matter, Atmos. Chem. Phys., 11, 1155–1165, <a href="http://dx.doi.org/10.5194/acp-11-1155-2011">https://doi.org/10.5194/acp-11-1155-2011</a>, 2011.

Elbert, W., Taylor, P. E., Andreae, M. O., and Pöschl, U.: Contribution of fungi to primary biogenic aerosols in the atmosphere: wet and dry discharged spores, carbohydrates, and inorganic ions, Atmos. Chem. Phys., 7, 4569–4588, <a href="http://dx.doi.org/10.5194/acp-7-4569-2007">https://doi.org/10.5194/acp-7-4569-2007</a>, 2007.

Fergenson, D. P., Pitesky, M. E., Tobias, H. J., Steele, P. T., Czerwieniec, G. A., Russell, S. C., Lebrilla, C. B., Horn, J. M., Coffee, K. R., Srivastava, A., Pillai, S. P., Shih, M. T. P., Hall, H. L., Ramponi, A. J., Chang, J. T., Langlois, R. G., Estacio, P. L., Hadley, R. T., Frank, M., and Gard, E. E.: Reagentless detection and classification of individual bioaerosol particles in seconds, Anal. Chem., 76, 373–378, <a href="http://dx.doi.org/10.1021/Ac034467e">https://doi.org/10.1021/Ac034467e</a>, 2004.

Fraser, M. P. and Lakshmanan, K.: Using levoglucosan as a molecular marker for the long-range transport of biomass combustion aerosols, Environ. Sci. Technol., 34, 4560–4564, <a href="http://dx.doi.org/10.1021/es991229l">https://doi.org/10.1021/es991229l</a>, 2000.

Freutel, F.: Identifizierung charakteristischer massenspektrometrischer Marker für primäre biologische Aerosolpartikel, Diploma Thesis, University Mainz, 2009.

Graham, B., Guyon, P., Maenhaut, W., Taylor, P. E., Ebert, M., Matthias-Maser, S., Mayol-Bracero, O. L., Godoi, R. H. M., Artaxo, P., Meixner, F. X., Moura, M. A. L., Rocha, C., Van Grieken, R., Glovsky, M. M., Flagan, R. C., and Andreae, M. O.: Composition and diurnal variability of the natural Amazonian aerosol, J. Geophys. Res.-Atmos., 108, 4765, <a href="http://dx.doi.org/10.1029/2003jd004049">https://doi.org/10.1029/2003jd004049</a>, 2003a.

Graham, B., Guyon, P., Taylor, P. E., Artaxo, P., Maenhaut, W., Glovsky, M. M., Flagan, R. C., and Andreae, M. O.: Organic compounds present in the natural Amazonian aerosol: Characterization by gas chromatography-mass spectrometry, J. Geophys. Res.-Atmos., 108, 4766, <a href="http://dx.doi.org/10.1029/2003jd003990">https://doi.org/10.1029/2003jd003990</a>, 2003b.

Hinds, W. C.: Aerosol technology – properties, behaviour, and measurements of airborne particles, 2nd ed., John Wiley & Sons, Inc., New York, 1999.

Hoose, C., Kristjansson, J. E., and Burrows, S. M.: How important is biological ice nucleation in clouds on a global scale?, Environ. Res. Lett., 5, 024009, <a href="http://dx.doi.org/10.1088/1748-9326/5/2/024009">https://doi.org/10.1088/1748-9326/5/2/024009</a>, 2010.

Huffman, A., Garland, R. M., and Pöschl, U.: Fluorescent biological aerosol particle concentrations and size distributions in pristine rainforest air during AMAZE-08, to be submitted to Atmos. Chem. Phys. Discuss., 2011.

Huffman, J. A., Docherty, K. S., Aiken, A. C., Cubison, M. J., Ulbrich, I. M., DeCarlo, P. F., Sueper, D., Jayne, J. T., Worsnop, D. R., Ziemann, P. J., and Jimenez, J. L.: Chemically-resolved aerosol volatility measurements from two megacity field studies, Atmos. Chem. Phys., 9, 7161–7182, <a href="http://dx.doi.org/10.5194/acp-9-7161-2009">https://doi.org/10.5194/acp-9-7161-2009</a>, 2009.

Huffman, J. A., Treutlein, B., and Pöschl, U.: Fluorescent biological aerosol particle concentrations and size distributions measured with an Ultraviolet Aerodynamic Particle Sizer (UV-APS) in Central Europe, Atmos. Chem. Phys., 10, 3215–3233, <a href="http://dx.doi.org/10.5194/acp-10-3215-2010">https://doi.org/10.5194/acp-10-3215-2010</a>, 2010.

Iannone, R., Chernoff, D. I., Pringle, A., Martin, S. T., and Bertram, A. K.: The ice nucleation ability of one of the most abundant types of fungal spores found in the atmosphere, Atmos. Chem. Phys., 11, 1191–1201, <a href="http://dx.doi.org/10.5194/acp-11-1191-2011">https://doi.org/10.5194/acp-11-1191-2011</a>, 2011.

Jaenicke, R.: Abundance of cellular material and proteins in the atmosphere, Science, 308, 73–73, 2005.

Jaenicke, R., Matthias-Maser, S., and Gruber, S.: Omnipresence of biological material in the atmosphere, Environ. Chem., 4, 217–220, <a href="http://dx.doi.org/10.1071/en07021">https://doi.org/10.1071/en07021</a>, 2007.

Jones, A. M. and Harrison, R. M.: The effects of meteorological factors on atmospheric bioaerosol concentrations – a review, Sci. Total Environ., 326, 151–180, <a href="http://dx.doi.org/10.1016/j.scitotenv.2003.11.021">https://doi.org/10.1016/j.scitotenv.2003.11.021</a>, 2004.

Kroll, J. H., Smith, J. D., Che, D. L., Kessler, S. H., Worsnop, D. R., and Wilson, K. R.: Measurement of fragmentation and functionalization pathways in the heterogeneous oxidation of oxidized organic aerosol, Phys. Chem. Chem. Phys., 11, 8005–8014, <a href="http://dx.doi.org/10.1039/B905289e">https://doi.org/10.1039/B905289e</a>, 2009.

Lee, T., Sullivan, A. P., Mack, L., Jimenez, J. L., Kreidenweis, S. M., Onasch, T. B., Worsnop, D. R., Malm, W., Wold, C. E., Hao, W. M., and Collett, J. L.: Chemical Smoke Marker Emissions During Flaming and Smoldering Phases of Laboratory Open Burning of Wildland Fuels, Aerosol Sci. Technol., 44, I–V, <a href="http://dx.doi.org/10.1080/02786826.2010.499884">https://doi.org/10.1080/02786826.2010.499884</a>, 2010.

Liu, P. S. K., Deng, R., Smith, K. A., Williams, L. R., Jayne, J. T., Canagaratna, M. R., Moore, K., Onasch, T. B., Worsnop, D. R., and Deshler, T.: Transmission efficiency of an aerodynamic focusing lens system: Comparison of model calculations and laboratory measurements for the Aerodyne Aerosol Mass Spectrometer, Aerosol Sci. Technol., 41, 721–733, <a href="http://dx.doi.org/10.1080/02786820701422278">https://doi.org/10.1080/02786820701422278</a>, 2007.

Mahowald, N., Jickells, T. D., Baker, A. R., Artaxo, P., Benitez-Nelson, C. R., Bergametti, G., Bond, T. C., Chen, Y., Cohen, D. D., Herut, B., Kubilay, N., Losno, R., Luo, C., Maenhaut, W., McGee, K. A., Okin, G. S., Siefert, R. L., and Tsukuda, S.: Global distribution of atmospheric phosphorus sources, concentrations and deposition rates, and anthropogenic impacts, Global Biogeochem. Cy., 22, GB4026, <a href="http://dx.doi.org/10.1029/2008gb003240">https://doi.org/10.1029/2008gb003240</a>, 2008.

Martin, S. T., Andreae, M. O., Althausen, D., Artaxo, P., Baars, H., Borrmann, S., Chen, Q., Farmer, D. K., Guenther, A., Gunthe, S. S., Jimenez, J. L., Karl, T., Longo, K., Manzi, A., Müller, T., Pauliquevis, T., Petters, M. D., Prenni, A. J., Pöschl, U., Rizzo, L. V., Schneider, J., Smith, J. N., Swietlicki, E., Tota, J., Wang, J., Wiedensohler, A., and Zorn, S. R.: An overview of the Amazonian Aerosol Characterization Experiment 2008 (AMAZE-08), Atmos. Chem. Phys., 10, 11415–11438, <a href="http://dx.doi.org/10.5194/acp-10-11415-2010">https://doi.org/10.5194/acp-10-11415-2010</a>, 2010a.

Martin, S. T., Andreae, M. O., Artaxo, P., Baumgardner, D., Chen, Q., Goldstein, A. H., Guenther, A., Heald, C. L., Mayol-Bracero, O. L., McMurry, P. H., Pauliquevis, T., Pöschl, U., Prather, K. A., Roberts, G. C., Saleska, S. R., Dias, M. A. S., Spracklen, D. V., Swietlicki, E., and Trebs, I.: Sources and properties of Amazonian aerosol particles, Rev. Geophys., 48, Rg2002, <a href="http://dx.doi.org/10.1029/2008rg000280">https://doi.org/10.1029/2008rg000280</a>, 2010b.

Matsumoto, K. and Uematsu, M.: Free amino acids in marine aerosols over the western North Pacific Ocean, Atmos. Environ., 39, 2163–2170, <a href="http://dx.doi.org/10.1016/j.atmosenv.2004.12.022">https://doi.org/10.1016/j.atmosenv.2004.12.022</a>, 2005.

Matthias-Maser, S. and Jaenicke, R.: The size distribution of primary biological aerosol particles with radii >0.2 μm in an urban rural influenced region, Atmos. Res., 39, 279–286, 1995.

Möhler, O., DeMott, P. J., Vali, G., and Levin, Z.: Microbiology and atmospheric processes: the role of biological particles in cloud physics, Biogeosciences, 4, 1059–1071, <a href="http://dx.doi.org/10.5194/bg-4-1059-2007">https://doi.org/10.5194/bg-4-1059-2007</a>, 2007.

Möhler, O., Georgakopoulos, D. G., Morris, C. E., Benz, S., Ebert, V., Hunsmann, S., Saathoff, H., Schnaiter, M., and Wagner, R.: Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions, Biogeosciences, 5, 1425–1435, <a href="http://dx.doi.org/10.5194/bg-5-1425-2008">https://doi.org/10.5194/bg-5-1425-2008</a>, 2008.

Mohr, C., Huffman, J. A., Cubison, M. J., Aiken, A. C., Docherty, K. S., Kimmel, J. R., Ulbrich, I. M., Hannigan, M., and Jimenez, J. L.: Characterization of Primary Organic Aerosol Emissions from Meat Cooking, Trash Burning, and Motor Vehicles with High-Resolution Aerosol Mass Spectrometry and Comparison with Ambient and Chamber Observations, Environ. Sci. Technol., 43, 2443–2449, <a href="http://dx.doi.org/10.1021/es8011518">https://doi.org/10.1021/es8011518</a>, 2009.

Morris, C. E., Georgakopoulos, D. G., and Sands, D. C.: Ice nucleation active bacteria and their potential role in precipitation, Journal De Physique IV, 121, 87–103, <a href="http://dx.doi.org/10.1051/jp4:2004121004">https://doi.org/10.1051/jp4:2004121004</a>, 2004.

Munk, K.: Biochemie, Zellbiologie, Ökologie, Evolution, Spektrum Akademischer Verlag, Heidelberg, 2000.

Pöschl, U., Martin, S. T., Sinha, B. W., Chen, Q., Gunthe, S. S., Huffman, J. A., Borrmann, S., Farmer, D., Garland, R. M., Helas, G., Jimenez, J. L., King, S. M., Manzi, A., Mikhailov, E., Pauliquevis, T., Petters, M. D., Prenni, A. J., Roldin, P., Rose, D., Schneider, J., Su, H., Zorn, S. R., Artaxo, P., and Andreae, M. O.: Rainforest aerosols as biogenic nuclei of clouds and precipitation in the Amazon, Science, 329, 1513–1516, 2010.

Pratt, K. A., DeMott, P. J., French, J. R., Wang, Z., Westphal, D. L., Heymsfield, A. J., Twohy, C. H., Prenni, A. J., and Prather, K. A.: In situ detection of biological particles in cloud ice-crystals, Nature Geosci., 2, 397–400, <a href="http://dx.doi.org/10.1038/ngeo521">https://doi.org/10.1038/ngeo521</a>, 2009.

Prenni, A. J., Petters, M. D., Kreidenweis, S. M., Heald, C. L., Martin, S. T., Artaxo, P., Garland, R. M., Wollny, A. G., and Pöschl, U.: Relative roles of biogenic emissions and Saharan dust as ice nuclei in the Amazon basin, Nature Geosci., 2, 401–404, <a href="http://dx.doi.org/10.1038/ngeo517">https://doi.org/10.1038/ngeo517</a>, 2009.

Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., and Simoneit, B. R. T.: Sources of fine organic aerosol 4. Particulate abrasion products from leaf surfaces of urban plants, Environ. Sci. Technol., 27, 2700–2711, <a href="http://dx.doi.org/10.1021/es00049a008">https://doi.org/10.1021/es00049a008</a>, 1993.

Russell, S. C., Czerwieniec, G., Lebrilla, C., Tobias, H., Fergenson, D. P., Steele, P., Pitesky, M., Horn, J., Srivastava, A., Frank, M., and Gard, E. E.: Toward understanding the ionization of biomarkers from micrometer particles by bio-aerosol mass spectrometry, J. Am. Soc. Mass Spectrom., 15, 900–909, 2004.

Schneider, J., Weimer, S., Drewnick, F., Borrmann, S., Helas, G., Gwaze, P., Schmid, O., Andreae, M. O., and Kirchner, U.: Mass spectrometric analysis and aerodynamic properties of various types of combustion-related aerosol particles, Int. J. Mass Spectrom., 258, 37–49, 2006.

Silva, P. J. and K. A. Prather: Interpretation of mass spectra from organic compounds in aerosol time-of-flight mass spectrometry, Anal. Chem., 72, 3553–3562, 2000.

Simoneit, B. R. T., Schauer, J. J., Nolte, C. G., Oros, D. R., Elias, V. O., Fraser, M. P., Rogge, W. F., and Cass, G. R.: Levoglucosan, a tracer for cellulose in biomass burning and atmospheric particles, Atmos. Environ., 33, 173–182, 1999.

Spiteller, G.: Massenspektrometrische Strukturanalyse organischer Verbindungen, Verlag Chemie, Weinheim, 1966.

Spracklen, D. V., Carslaw, K. S., Merikanto, J., Mann, G. W., Reddington, C. L., Pickering, S., Ogren, J. A., Andrews, E., Baltensperger, U., Weingartner, E., Boy, M., Kulmala, M., Laakso, L., Lihavainen, H., Kivekäs, N., Komppula, M., Mihalopoulos, N., Kouvarakis, G., Jennings, S. G., O'Dowd, C., Birmili, W., Wiedensohler, A., Weller, R., Gras, J., Laj, P., Sellegri, K., Bonn, B., Krejci, R., Laaksonen, A., Hamed, A., Minikin, A., Harrison, R. M., Talbot, R., and Sun, J.: Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation, Atmos. Chem. Phys., 10, 4775–4793, <a href="http://dx.doi.org/10.5194/acp-10-4775-2010">https://doi.org/10.5194/acp-10-4775-2010</a>, 2010.

Sun, Y., Zhang, Q., Macdonald, A. M., Hayden, K., Li, S. M., Liggio, J., Liu, P. S. K., Anlauf, K. G., Leaitch, W. R., Steffen, A., Cubison, M., Worsnop, D. R., van Donkelaar, A., and Martin, R. V.: Size-resolved aerosol chemistry on Whistler Mountain, Canada with a high-resolution aerosol mass spectrometer during INTEX-B, Atmos. Chem. Phys., 9, 3095–3111, <a href="http://dx.doi.org/10.5194/acp-9-3095-2009">https://doi.org/10.5194/acp-9-3095-2009</a>, 2009.

Taylor, P. E., Flagan, R. C., Valenta, R., and Glovsky, M. M.: Release of allergens as respirable aerosols: A link between grass pollen and asthma, Journal of Allergy and Clinical Immunology, 109, 51–56, <a href="http://dx.doi.org/10.1067/mai.2002.120759">https://doi.org/10.1067/mai.2002.120759</a>, 2002.

Taylor, P. E., Flagan, R. C., Miguel, A. G., Valenta, R., and Glovsky, M. M.: Birch pollen rupture and the release of aerosols of respirable allergens, Clinical and Experimental Allergy, 34, 1591–1596, <a href="http://dx.doi.org/10.1111/j.1365-2222.2004.02078.x">https://doi.org/10.1111/j.1365-2222.2004.02078.x</a>, 2004.

Tuch, T. M., Haudek, A., Müller, T., Nowak, A., Wex, H., and Wiedensohler, A.: Design and performance of an automatic regenerating adsorption aerosol dryer for continuous operation at monitoring sites, Atmos. Meas. Tech., 2, 417–422, <a href="http://dx.doi.org/10.5194/amt-2-417-2009">https://doi.org/10.5194/amt-2-417-2009</a>, 2009.

von Blohn, N., Mitra, S. K., Diehl, K., and Borrmann, S.: The ice nucleating ability of pollen: Part III: New laboratory studies in immersion and contact freezing modes including more pollen types, Atmos. Res., 78, 182–189, <a href="http://dx.doi.org/10.1016/j.atmosres.2005.03.008">https://doi.org/10.1016/j.atmosres.2005.03.008</a>, 2005.

Watson, J. D., Baker, T. A., Bell, S. P., Gann, A. A. F., Levine, M., and Losick, R. M.: Molecular biology of the gene, 6th ed., Benjamin Cummings, 2007.

Yttri, K. E., Dye, C., and Kiss, G.: Ambient aerosol concentrations of sugars and sugar-alcohols at four different sites in Norway, Atmos. Chem. Phys., 7, 4267–4279, <a href="http://dx.doi.org/10.5194/acp-7-4267-2007">https://doi.org/10.5194/acp-7-4267-2007</a>, 2007.