Abstract
A continuous dichotomous beta gauge monitor was used to characterize the hourly content of PM<sub>2.5</sub>, PM<sub>10-2.5</sub>, and Black Carbon (BC) over a 12-month period in an urban street canyon of Hong Kong. Hourly vehicle counts for nine vehicle classes and meteorological data were also recorded. The average weekly cycles of PM<sub>2.5</sub>, PM<sub>10-2.5</sub>, and BC suggested that all species are related to traffic, with high concentrations on workdays and low concentrations over the weekends. PM<sub>2.5</sub> exhibited two comparable concentrations at 10:00-11:00 (63.4 μg/m<sup>3</sup>) and 17:00-18:00 (65.0 μg/m<sup>3</sup>) local time (LT) during workdays, corresponding to the hours when the numbers of diesel-fueled and gasoline-fueled vehicles were at their maximum levels: 3179 and 2907 h<sup>-1</sup>, respectively. BC is emitted mainly by diesel-fueled vehicles and this showed the highest concentration (31.2 μg/m<sup>3</sup>) during the midday period (10:00-11:00 LT) on workdays. A poor correlation was found between PM<sub>2.5</sub> concentration and wind speed (R = 0.51, P-value > 0.001). In contrast, the concentration of PM<sub>10-2.5</sub> was found to depend upon wind speed and it increased with obvious statistical significance as wind speed increased (R = 0.98, P-value < 0.0001).
Original language | English |
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Pages (from-to) | 134-140 |
Number of pages | 7 |
Journal | Particuology |
Volume | 20 |
DOIs | |
Publication status | Published - 1 Jan 2015 |
Keywords
- BC
- Hong Kong
- PM<inf>10-2.5</inf>
- PM<inf>2.5</inf>
- Urban street canyon
ASJC Scopus subject areas
- General Chemical Engineering
- General Materials Science
- Condensed Matter Physics