On the growth of nucleation mode particles: source rates of condensable vapor in polluted and clean environments
1Department of Physical Sciences, University of Helsinki, P.O. BOX 64, FIN-00014 Helsinki, Finland
2Finnish Meteorological Institute and University of Kuopio, P.O. BOX 1627, FIN-70211 Kuopio, Finland
3Finnish Meteorological Institute, Air Quality Research, Sahaajankatu 20E, FIN-00880 Helsinki, Finland
Abstract. The growth properties of nucleation mode particles were investigated. The variation of source rates of condensable vapors in different locations and environmental conditions was analyzed. The measurements were performed in background stations in Antarctica and in Finnish Lapland and Boreal Forest stations (SMEAR I and SMEAR II) as well as in polluted urban sites in Athens, Marseille and New Delhi. Taking advantage of only the measured aerosol particles spectral evolution as a function of time the formation and growth properties of nucleation mode aerosols have been evaluated. The diameter growth-rate and condensation sink have been obtained from the measured size distribution dynamics. Using this growth rate and condensation sink, the concentration of condensable vapours and their source rate have been estimated. The growth rates and condensation sinks were between 0.3–20 nm h−1 and 10−4–0.07 s−1, respectively. The corresponding source rate of condensable vapors varied more than 4 orders of magnitude from 103 to over 107 cm−1 s−1. The highest condensation sink and source rate values were observed in New Delhi and the smallest values in Antarctica.