Microscopic morphology and size distribution of particles in PM 2.5 of Guangzhou City

Xidan Feng, Zhi Dang, Weilin Huang, Longyi Shao, Weijun Li

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Samples of airborne PM2.5 particles in Guangzhou urban area were collected during the autumn of 2006 and the spring of 2007. The morphologies and elemental compositions of individual particles were determined by Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectrometer (SEM-EDX). The obtained images were further analyzed for size distribution by an image analysis system. Based on the morphology, particles in PM2.5 were classified into four groups: soot aggregates, minerals, fly ash and others. The amount of soot aggregates and minerals were higher than that of fly ashes. The distributions of particles by number and size in two seasons were bimodal with 90% less than 1.0 μm in diameter. The primary peak from the autumn samples was in the size range of 0.4∈∼∈0.5 μm, and 0. 3∈∼∈0.4 μm for the spring samples. More soot aggregates (36.1%) and minerals (61.5%) were found than fly ash (2.4%) in autumn, but soot aggregates (89.9%) was the dominant particle type in spring. The size distribution of particles according to the volume was generally opposite to that according to the number. Particles less than 1.0 μm were as high as 89.5% in number but contributed only 18.9% in volume, indicating that fine particles contributed relatively little in volume although existing in large numbers.

Original languageAmerican English
Pages (from-to)37-51
Number of pages15
JournalJournal of Atmospheric Chemistry
Volume64
Issue number1
DOIs
StatePublished - Sep 2009

ASJC Scopus subject areas

  • Environmental Chemistry
  • Atmospheric Science

Keywords

  • Atmospheric particulate
  • PM
  • SEM-EDX
  • Size distribution

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