New particle formation in the polluted continental boundary layer was studied, based on 1.5-year observations of the particle size distribution, meteorological and gas phase parameters. Events of new particle formation involving significant ultrafine particle number concentrations (> 10 4 cm -3 in the size range 3-11 nm) were observed on 20 % of all days, pointing out that a frequent particle production from gaseous precursors can occur despite the relatively high pre-existing particle surface area in the area of investigation. The maximum in the observed particle size distributions was mostly above 3 nm, suggesting the actual particle nucleation to take place upwind of the measurement site. A particle growth analysis yielded 2.3 ± 1.4 h as an upper limit of the time for the particles to grow from the critical cluster size till the observation of the peak in ultrafine number concentration. On 80 % of the significant events of new particle formation (though not on all), SO 2 concentrations increased considerably (by an average factor of 7), most likely by entrainment from aloft. Particle surface area was, on average, higher on event days compared to non-event days, indicating only a weak competition between condensation onto the pre-existing particle surface area and the new particle formation process. The highest statistical correlation was found between the events of new particle formation and solar radiation, indicating a high degree of meteorological control.
CITATION STYLE
Birmili, W., & Wiedensohler, A. (2000). New particle formation in the continental boundary layer: Meteorological and gas phase parameter influence. Geophysical Research Letters, 27(20), 3325–3328. https://doi.org/10.1029/1999GL011221
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