Particle number size distribution and new particle formation: New characteristics during the special pollution control period in Beijing

Jian Gao, Fahe Chai, Tao Wang, Shulan Wang, Wenxing Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

51 Citations (Scopus)


New particle formation is a key process in shaping the size distribution of aerosols in the atmosphere. We present here the measurement results of number and size distribution of aerosol particles (10-10000 nm in diameter) obtained in the summer of 2008, at a suburban site in Beijing, China. We firstly reported the pollution level, particle number size distribution, diurnal variation of the particle number size distribution and then introduced the characteristics of the particle formation processes. The results showed that the number concentration of ultrafine particles was much lower than the values measured in other urban or suburban areas in previous studies. Sharp increases of ultrafine particle count were frequently observed at noon. An examination of the diurnal pattern suggested that the burst of ultrafine particles was mainly due to new particle formation promoted by photochemical processes. In addition, high relative humidity was a key factor driving the growth of the particles in the afternoon. During the 2-month observations, new particle formation from homogeneous nucleation was observed for 42.7% of the study period. The average growth rate of newly formed particles was 3.2 nm/hr, and varied from 1.2 to 8.0 nm/hr. The required concentration of condensable vapor was 4.4 × 107cm-3, and its source rate was 1.2 × 106cm-3sec-1. Further calculation on the source rate of sulphuric acid vapor indicated that the average participation of sulphuric acid to particle growth rates was 28.7%.
Original languageEnglish
Pages (from-to)14-21
Number of pages8
JournalJournal of Environmental Sciences
Issue number1
Publication statusPublished - 1 Jan 2012


  • Beijing
  • Condensational sink
  • New particle formation
  • Particle number size distribution
  • Sulphuric acid

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Environmental Science(all)

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