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New particle formation in the continental boundary layer: Meteorological and gas phase parameter influence
Author(s) -
Birmili Wolfram,
Wiedensohler Alfred
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl011221
Subject(s) - particle (ecology) , particle number , nucleation , particle size , range (aeronautics) , boundary layer , condensation , atmospheric sciences , particle size distribution , environmental science , materials science , physics , meteorology , mechanics , chemistry , geology , thermodynamics , oceanography , volume (thermodynamics) , composite material
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.