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Volume 15, No. 6, November 2015, Pages 2305-2319 PDF(5.35 MB)  Supplementary MaterialPDFPDF (1.29 MB)
doi: 10.4209/aaqr.2015.04.0271   

Ultrafine Particles and PM2.5 at Three Urban Air Monitoring Stations in Northern Taiwan from 2011 to 2013

Guan-Yu Lin1, Guo-Rui Lee1, Sih-Fan Lin1, Yi-Hung Hung1, Shih-Wei Li2, Guo-Jei Wu2, Huajun Ye3, Wei Huang3, Chuen-Jinn Tsai1

1 Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan
2 Environmental Analysis Laboratory, Environmental Protection Administration, Jongli, 320, Taiwan
3 Focused Photonics (Hangzhou), Inc., Hangzhou, 310052, China


  • High UFPs average mass concentrations are due to the impact by heavy traffic emission and NPF.
  • Meteorological conditions also have effects on the variation of UFPs and PM2.5.
  • The 3-year average mass distributions all show diurnal bimodal distributions.
  • Calculated χi at ZS were larger than 1, suggesting that the shape of particles was irregular.



In this study, long term measurements of PM2.5 and ultrafine particles (UFPs) for daily average mass concentration at Zhongshan (ZS), Sinjhuang (SJ), and Jhudong (JD) urban air monitoring stations were conducted from 2011 spring to 2013 autumn. The results showed that daily average UFPs mass concentrations in spring (average at 3 stations: 1.58 ± 0.74 µg m–3) and summer (average at 3 stations: 1.59 ± 0.53 µg m–3) were higher than those in autumn (average at 3 stations: 1.02 ± 0.28 µg m–3) and winter (average at 3 stations: 1.04 ± 0.48 µg m–3) due to the impacts by heavy traffic emission and new particle formation event. The effective density (ρeff) and dynamic shape factor (χ) for ultrafine particles (UFPs) were found to be 0.68 ± 0.16 g cm–3 and 2.06 ± 0.19, respectively, suggesting that the particle morphology was irregular shape. Based on the calculated ρeff and χ, the average number and surface area concentration ratio of UFPs to those of PM2.5 at these monitoring stations was determined to be 89.0 ± 5.5% and 42.1 ± 12.8%, respectively, suggesting that UFPs contribute significantly to the health-relevant PM2.5 aerosol fraction in these stations.



Keywords: PM2.5; Nanoparticle measurement; Ultrafine particles; Effective density.



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