Atmospheric Chemistry and Physics Discussions
www.atmos-chem-phys-discuss.net
1680-7367
1680-7375
8
2
2008
10.5194/acpd-8-6313-2008
http://www.atmos-chem-phys-discuss.net/8/6313/2008/
http://www.atmos-chem-phys-discuss.net/8/6313/2008/acpd-8-6313-2008.html
http://www.atmos-chem-phys-discuss.net/8/6313/2008/acpd-8-6313-2008.pdf
6313
6353
2008-03-27
Basic characteristics of atmospheric particles, trace gases and meteorology in a relatively clean Southern African Savannah environment
L. Laakso
lauri.laakso@iki.fi
H. Laakso
P. P. Aalto
P. Keronen
T. Petäjä
T. Nieminen
T. Pohja
E. Siivola
M. Kulmala
N. Kgabi
M. Molefe
D. Mabaso
D. Phalatse
K. Pienaar
V.-M. Kerminen
Department of Physics, University of Helsinki, P. O. BOX 64, 00014 Helsinki, Finland
Department of Physics, North-West University, Private Bag X 2046, Mmabatho, South Africa
Department of Biology, North-West University, Private Bag X 2046, Mmabatho, South Africa
School of Chemistry, North-West University, Private Bag X 6001, Potchefstroom, South Africa
Finnish Meteorological Institute, P.O. Box 503, 00101 Helsinki, Finland
We have analyzed one year (July 2006–July 2007) of measurement data from
a relatively clean background site located in dry savannah in South Africa.
The annual-median trace gas concentrations were equal to 0.7 ppb for
SO<sub>2</sub>, 1.4 ppb for NOx, 36 ppb for O<sub>3</sub> and 105 ppb for CO. The
corresponding PM<sub>1</sub>, PM<sub>2.5</sub> and PM<sub>10</sub> concentrations were 9.0,
10.5 and 18.8 μg m<sup>−3</sup>, and the annual median total particle number
concentration in the size range 10–840 nm was 2340 cm<sup>−3</sup>. Gases and
particles had a clear seasonal and diurnal variation, which was associated
with field fires and biological activity together with local meteorology.
Atmospheric new-particle formation was observed to take place in more than
90% of the analyzed days. The days with no new particle formation were
cloudy or rainy days. The formation rate of 10 nm particles varied in the
range of 0.1–28 cm<sup>−3</sup> s<sup>−1</sup> (median 1.9 cm<sup>−3</sup> s<sup>−1</sup>) and
nucleation mode particle growth rates were in the range 3–21 nm h<sup>−1</sup>
(median 8.5 nm h<sup>−1</sup>). Due to high formation and growth rates, observed
new particle formation gives a significant contribute to the number of cloud
condensation nuclei budget, having a potential to affect the regional
climate forcing patterns.
Aalto, P., Hämeri, K., Becker, E., Weber, R., Salm, J., Mäkelä, J. M., Hoell, C., O'Dowd, C. D., Karlsson, H., Hansson, H.-C., Väkevä, M., Koponen, I. K., Buzorius, G., and Kulmala, M.: Physical characterization of aerosol particles during nucleation events, Tellus, 53B, 344–358, 2001.
Afeti, G. M., Resch, F. J., and Sunnu, A. K.: Size and number distributions of Harmattan dust aerosol in central Ghana, Suppl. I., J. Aerosol Sci., 29, 173–174, 1998.
Andreae, M. O., Chapuis, A., Cros, B., Fontan, J., Helas, G., Justice, C., Kaufman, Y. J., Minga, A., and Nganga, D.: Ozone and Aitken nuclei over equatorial Africa: Airborne observations during DECAFE88, J. Geophys. Res., 97, 6137–6148, 1992.
Boko, M., Niang, I., Nyong, A., Vogel, C., Githeko, A., Medany, M., Osman-Elasha, B., Tabo, R. and Yanda, P.: Africa, Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Parry, M. L., Canziani, O. F., Palutikof, J. P., Van der Linden, P. J., and Hanson, C. E., Cambridge University Press, Cambridge UK, 433–467, 2007.
Brook, J. R., Dann, T. F., and Burnett, R. T.: The relationship among TSP, PM$_10$, PM$_2.5$ and inorganic constituents of atmospheric particulate matter at multiple Canadian locations, J. Air Waste Manage., 47, 2–19, 1997.
Caminade, C. and Terray, L.: Influence of increased greenhouse gases and sulphate aerosols concentration upon diurnal temperature range over Africa at the end of the 20th century, Geophys. Res. Lett., 33, L15703, doi:10.1029/2006GL026381, 2006.
Carmichael, G., Ferm, M., Thongboonchooa, N., Woo, J., Chan, L. Y., Murano, K., Viet, P., Mossberg, C., Bala, R., Boonjawat, J., Upatum, P., Mohan, M., Adhikary, S., Shrestha, A., Pienaar, J., Brunke, E., Chen, T., Jie, T., Guoan, D., Peng, L., Dhiharto, S., Harjanto, H., Jose, A., Kimani, W., Kirouane, A., Lacaux, J.-P., Richard, S., Barturen, O., Cerda, J., Athayde, A., Tavares, T., Cotrina, J., and Bilici, E.: Measurements of sulfur dioxide, ozone and ammonia concentrations in Asia, Africa, and South America using passive samplers, Atmos. Environ., 37, 1293–1308, 2003.
Dal Maso, M., Kulmala, M., Riipinen, I., Wagner, R., Hussein, T., Aalto, P. P., and Lehtinen, K. E. J.: Formation and growth of fresh atmospheric aerosols: eight years of aerosol size distribution data from SMEAR II, Hyytiälä, Finland, Boreal Environ. Res., 10, 323–336, 2005.
Van Dingenen, R., Raes, F., Putaud, J.-P., Baltensperger, U., Charron, A., Facchini, M. C., Decesari, S., Fuzzi, S., Gehrig, R., Hansson, H.-C., Harrison, R.-M., Huglin, C., Jones, A., Laj, P., Lorbeer, G., Maenhaut, W., Palmgren, F., Querol, X., Rodriguez, S., Schneider, J., ten Brink, H., Tunved, P., Törseth, K., Wehner, B., Weingartner, E., Wiedensohler, A., and Wahlin, P.: A European aerosol phenomenology: physical characteristics of particulate matter at kerbside, urban, rural and background sites in Europe, Atmos. Environ., 38, 2561–2577, 2004.
Duncan, B. N., Logan, J. A., Bey, I., Megretskaia, I. A., Yantosca, R. M., Novelli, P. C., Jones N. B., and Rinsland, C. P.: Global budget of CO, 1988-1997: Source estimates and validation with a global model, J. Geophys. Res., 112, D22301, doi:10.1029/2007JD008459, 2007.
Eldred, R. A., Cahill, T. A., and Flocchini, R. G.: Composition of PM$_2.5$ and PM$_10$ aerosols in the IMPROVE network, J. Air Waste Manage., 47, 194–203, 1997.
Finlayson-Pitts, B. J. and Pitts, J. N.: Chemistry of Upper and Lower Atmosphere, Academic Press, San Diego, 2000.
Gatari, M., Wagner, A., and Boman, J.: Elemental composition of tropospheric aerosols in Hanoi, Vietnam and Nairobi, Kenya, Sci. Total Environ., 341, 241–249, 2005.
Güenther, A., Otter, L., Zimmermann, P., Greenberg, J., Scholes, R., and Scholes, M.: Biogenic hydrocarbon emissions from Southern African savannas, J. Geophys. Res., 101, 25 859–25 865, 1996.
Hamed, A., Joutsensaari, J., Mikkonen, S., Sogacheva, L., Dal Maso, M., Kulmala, M., Cavalli, F., Fuzzi, S., Facchini, M. C., Decesari, S., Mircea, M., Lehtinen, K. E. J., and Laaksonen, A.: Nucleation and growth of new particles in Po Valley, Italy, Atmos. Chem. Phys., 7, 355–376, 2007.
Helmig, D., Oltmans, S. J., Carlson, D., Lamarque, J.-F., Jones, A., Labuschagne, C., Anlauf, K., and Hayden, K.: A review of surface ozone in Polar Regions, Atmos. Environ., 41, 5238–5161, 2007.
Hobbs, P. V.: Clean air slots amid dense atmospheric pollution in Southern Africa, J. Geophys. Res., 108, 8490, doi: 10.1029/2002JD002156, 2003.
Holloway, T., Leby II, H., and Kasibhatla, P.: Global distribution of carbon monoxide, J. Geophys. Res., 105, 12 123-12 147, 2000.
Kerminen, V.-M., Lihavainen, H., Komppula, M., Viisanen, Y., and Kulmala, M.: Direct observational evidence linking atmospheric aerosol formation and cloud droplet activation, Geophys. Res. Lett., 32, L14803, doi:10.1029/2005GL02, 2005.
Kgabi, N. A.: Monitoring the levels of atmospheric particulate matter in the North West Province, PhD Thesis, North-West University, 2006.
Kulmala, M., Vehkamäki, H., Petäjä, T., Dal Maso, M., Lauri, A., Kerminen, V.-M., Birmili, W., and McMurry, P. H.: Formation and growth rates of ultrafine atmospheric particles: A review of observations, J. Aerosol Sci., 35, 143–176, 2004.
Kurtén, T., Kulmala, M., Dal Maso, M., Suni, T., Reissell, A., Vehkamäki, H., Hari, P., Laaksonen, A., Viisanen, Y., and Vesala, T.: Estimation of different forest-related contributions to the radiative balance using observation in southern Finland, Boreal Environ. Res., 8, 275–285, 2003.
Laakso, L., Koponen, I.K., Mönkkönen, P., Kulmala, M., Kerminen, V.-M., Wehner, B., Wiedensohler, A., Wu, Z., Hu, M.: Aerosol particles in the developing world; a comparison between New Delhi in India and Beijing in China, Water Air Soil Poll., 173(1–4), 5–20, 2006.
Levy II, H., Klonecki, A. A., and Kasibhatla, P. S.: Simulated tropospheric NOx: Its evaluation, global distribution and individual source contributions, J. Geophys. Res., 104, 25 273-26 306, 1999.
Mirme, A., Tamm, E., Mordas, G., Vana, M., Uin, J., Mirme, S., Bernotas, T., Laakso, L., Hirsikko, A., and Kulmala, M.: A wide-range multi-channel Air Ion Spectrometer, Boreal Environ. Res., 12, 247–264, 2007.
Mori, I., Nishikawa, M., Quan, H., and Morita, M.: Estimation of the concentration and chemical composition of Kosa aerosols at their origin, Atmos. Environ., 36, 4569–4575, 2002.
Otter, L. B., Yang, W., Scholes, M., and Meixner, F.: Nitric oxide emissions from a southern African savanna, J. Geophys. Res., 104, 18 471-18 486, 1999.
Otter, L., Güenther, A., Wiedinmyer, C., Fleming, G., Harley, P., and Greenberg, J.: Spatial and temporal variations in biegenic volatile organic compound emissions for Africa South of equator, J. Geophys. Res., 108, 8505, doi:10.1029/2002JD002609, 2003.
Piketh, S., Van Nierop, M., Rautenbach, C., Walton, N., Ross, K., Holmes, S., and Richards, T.: Rustenburg Local Muncipality Air Quality Management Plan, Palace consulting engineers ltd., Republic of South Africa, 2005.
Petäjä, T., Laakso, L., Pohja, T., Siivola, E., Laakso, H., Aalto, P.P., Keronen, P., Kgabi, N.A. and Kulmala, M.: Mobile air quality monitoring trailer for developing countries, Proceedings of International Conference on Nucleation and Atmospheric Aerosols 2007, Galway, Ireland, August 2007, edited by: O'Dowd, C. D. and Wagner, P. E., Springer, 694–697, 2007.
Ross, K. E., Piketh, S. J., Bruintjes, R. T., Burger, R. P., Swap, R. J. and Annegarn, H. J.: Spatial and seasonal variations in CCN distribution and the aerosol-CCN relationship over southern Africa, J. Geophys. Res., 108, 8481, doi:10.1029/2002JD002384, 2003.
Scheel, H. E., Areskoug, H., Geiss, H., Gomiscek, B., Granby, K., Haszpra, L., Klasinc, L., Kley, D., Laurila, T., Lindskog, A., Roemer, M., Schmitt, R., Simmonds, P., Solberg, S., and Tounape, G.: On the spatial distribution and seasonal variation of lower-tropospheric ozone over Europe, J. Atmos. Chem., 28, 11–28, 1997.
Sinha, P., Hobbs, P. V., Yokelson, R. J., Blake, D. R., Gao, S., and Kirchstetter, T.W.: Distributions of trace gases and aerosols during dry biomass burning season in Southern Africa, J. Geophys. Res., 108, 4536, doi:10.1029/2003JD003691, 2003
Solomon, P., Cowling, E., Hidy, E., and Furiness, C.: Comparison of scientific findings from major ozone field studies in North America and Europe, Atmos. Environ., 34, 1885–1920, 2000.
South African Weather Service: Climatologic statistics for Mafikeng, http://www.weathersa.co.za/Climat/Climstats/MmabathoStats.jsp, 2007.
Swap, R. J., Annegarn, H. J., Suttles, J. T., King, M. D., Platnick, S., Privette, J. L., and Scholes, R. J.: Africa burning: A thematic analysis of the Southern African Regional Science Initiative (SAFARI 2000), J. Geophys. Res., 108, 8465, doi:10.1029/2003JD003747, 2003.
Tammet, H.: Size and mobility of nanometer particles, clusters and ions, J. Aerosol Sci., 26, 459–475, 1995.
Tammet, H.: Reduction of air ion mobility to standard conditions, J. Geophys. Res., 103, 13 933–13 937, 1998.
Tyson, P. D., Garstang, M., and Swap, R.: Large-scale recirculation of Air over Southern Africa, J. Appl. Meteorol., 35, 2218–2236, 1996.
Went, F. W.: Blue hazes in the atmosphere, Nature, 187, 641–643, 1960.
Winklmayr, W., Reischl, G., Lindner, A., and Berner, A.: A new electromobility spectrometer for the measurement of aerosol size distributions in the size range from 1 to 1000 nm, J. Aerosol Sci., 22, 289–296, 1991.