AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Shrinkage of New Atmospheric Particles in an Urban Area of Southern Europe
Elisabeth Alonso-Blanco, F. Javier Gomez-Moreno, Lourdes Nunez, Manuel Pujadas, BEGONA ARTINANO, CIEMAT
Abstract Number: 464 Working Group: Advances in the Physics and Chemistry of New Particle Formation and Growth
Abstract New Particles Formation (NPF) processes involve a first formation phase of particles from precursors (gases, ions...) and a second phase of growth. Some authors as (1) (2) (3) and (4) have observed during the latter a sudden decreasing trend in the particle size, a.k.a. shrinkage.
Changes in meteorological conditions during the NPF process, especially, a wind speed and temperature increase can determine the occurrence of shrinkage processes (1;2). These changes facilitate the evaporation of semi-volatile species condensed in the recently formed aerosol. Shrinkage processes have been analyzed in an urban background site in Madrid (Spain) through the following measurements and instruments:
1) Scanning Mobility Particle Sizer (TSI-SMPS: DMA3081 with CPC 3775) providing aerosol size distribution (14-660 nm).
2) Differential Optical Absorption Spectrometer (DOAS: OPSIS AR-500) for ambient concentrations of NO, NO2 and O3.
3) Meteorological tower providing data on precipitation, pressure, temperature, relative humidity (RH) and wind speed and direction at the site.
A number of shrinkage processes have been characterized during NPF events linked to an increase of wind speed during the growth phase of the newly formed particles. Mostly, these occur during spring and summer, when nucleation takes place at this site.
References
(1) Cusack, M., Alastuey, A., & Querol, X., 2013. Atmospheric Environment, 81, 651-659.
(2) Young, L. H., Lee, S. H., Kanawade, V. P., Hsiao, T. C., Lee, Y. L., Hwang, B. F., Hsu, H. T., & Tsai, P. J., 2013. Atmospheric Chemistry & Physics, 13(2).
(3) Yao, X., Choi, M.Y., Lau, N.T., Lau, A.P.S., Chan, C.K., Fang, M., 2010. Aerosol Science and Technology 44, 639-650.
Acknowledgments: This work has been supported by the Spanish Ministry of Science and Innovation through projects MICROSOL (CGL2011-27020). E. Alonso-Blanco acknowledges the FPI grant to carry out the doctoral thesis/PhD at the Research Center for Energy, Environment and Technology (CIEMAT).