Enhancement effect of relative humidity on the formation and regional respiratory deposition of secondary organic aerosol

Kuo Pin Yu*, Chi Chi Lin, Shang Chun Yang, Ping Zhao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

In this study, we investigated the effect of relative humidity (RH) on the formation of secondary organic aerosol (SOA) generated from the ozonolysis of d-limonene in an environmental chamber. The mass yield and the number concentration of SOA increased seven and eight times, respectively, when the RH increased from 18% to 82%. The measured total loss rates (apparent loss rates) of the number and mass concentration of SOA in the chamber ranged from 1.70 to 1.77h-1 and from 2.51 to 2.61h-1, respectively, at a controlled ventilation rate of 0.72±0.04h-1. The wall-deposition-loss-rate coefficient observed (1.00±0.02h-1) was approximate to the estimated value based on Zhao and Wu's model [1] which includes the factors of turbulence, Brownian diffusion, turbophoresis and surface roughness. According to the ICRP (International Commission on Radiological Protection) model, the inhaled SOA particles are deposited primarily in the alveoli of the lung. The integrated alveolar deposited dose of the mass (surface area) of SOA over 3h accounted for 74.0-74.8% (74.3-74.9%) of the total deposited dose at the investigated RH. Raising the RH resulted in the growth of SOA particle sizes and increment of the deposition dose but did not cause significant changes in the ratio of regional to the total respiratory deposition of SOA.

Original languageEnglish
Pages (from-to)94-102
Number of pages9
JournalJournal of Hazardous Materials
Volume191
Issue number1-3
DOIs
StatePublished - 15 Jul 2011

Keywords

  • D-Limonene
  • Environmental chamber
  • Nanoparticles
  • Ozone
  • Wall loss

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