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In-Cabin Commuter Exposure to Ultrafine Particles on Commuter Roads in and around Hong Kong’s Tseung Kwan O Tunnel

Category: Articles

Volume: 9 | Issue: 3 | Pages: 353-357
DOI: 10.4209/aaqr.2008.09.0041

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To cite this article:
Kaminsky, J.A., Gaskin, E.A., Matsuda, M. and Miguel, A.H. (2009). In-Cabin Commuter Exposure to Ultrafine Particles on Commuter Roads in and around Hong Kong’s Tseung Kwan O Tunnel. Aerosol Air Qual. Res. 9: 353-357. doi: 10.4209/aaqr.2008.09.0041.

Jason A. Kaminsky1, Emily A.L.M. Gaskin2, Masanori Matsuda3, Antonio H. Miguel4

  • 1 Graduate School of Business, Interdisciplinary Program in Environment and Resources, Yang and Yamzaki Environment and Energy Building-4210, 473 Via Ortega, Stanford University, Stanford, CA 94305, USA
  • 2 National Oceanic and Atmospheric Administration, Fagatele Bay National Marine Sanctuary, Executive Office Building, Utulei, Pago Pago, American Samoa, 96799, USA
  • 3 Toyota Motor Corporation, Operation Department Vehicle Logistics Division, 4-7-1 Meieki, Nakamura-ku,Nagoya 450-8711 , Japan
  • 4 Haagen-Smit Laboratory, California Air Resources Board, 9528 Telstar Ave., El Monte, CA 91731, USA


Over half a million cars pass through Hong Kong’s tunnels every day. Commuters, taxi drivers, and other drivers who pass through these tunnels may be exposed to high levels of particulate matter and toxic gases present in the air. There is limited data on in-cabin exposure to pollutants, especially while the vehicle is driving through a tunnel under different cabin ventilation conditions. This study reports in-cabin measurements of fine particles (FP, dp < 2.5 μm) -- which includes nanoparticles and ultrafine particles (UFP, dp < 100 nm) -- in a 1998 Nissan Sunny EX passenger car while driving through Hong Kong’s Tseung Kwan O Tunnel. The vehicle tested did not contain a particle filtration system or an activated carbon filter, and was fueled with unleaded gasoline. The measurements were taken using a water-based condensation particle counter (WCPC) under different conditions consistent with driver behavior. The particle count readings were generally highest with the windows closed and air conditioning on. On average, these readings were more than three times higher than readings with the windows closed and the air conditioning off, and 68% higher than readings with the windows open and the air conditioning off. In-cabin particle concentrations inside the tunnel were up to twenty-one times higher than in-cabin particle concentrations outside the tunnel under comparable traffic conditions. The highest in-cabin particle count concentration reading, 1.94 million particles/cm3, was taken with the windows closed and air conditioning on while the test car was passing a double-decker diesel bus.


In-cabin commuter exposure Water-based particle counter Hong Kong Tseung Kwan O Tunnel Roadway measurements Ultrafine particles Nano-particles

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