Real-time measurements of PM2.5, PM10–2.5, and BC in an urban street canyon--颗粒学报PARTICUOLOGY

Cheng, Y., Lee, S. C., Gao, Y., Cui, L., Deng, W., Cao, J., Shen, Z., & Sun, J. (2015). Real-time measurements of PM2.5, PM10–2.5, and BC in an urban street canyon. Particuology, 20, 134–140. https://doi.org/10.1016/j.partic.2014.08.006

Real-time measurements of PM_2.5, PM_10–2.5, and BC in an urban street canyon

Yan Cheng ^{a b *}, Shun Cheng Lee ^c, Yuan Gao ^c, Long Cui ^c, Wenjing Deng ^d, Junji Cao ^b, Zhenxing Shen ^a, Jian Sun ^c

a Department of Environmental Science and Technology, School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an 710049, China
b SKLLQG, Institute of Earth and Environment, CAS, Xi’an 710075, China
c Department of Civil and Environmental Engineering, Research Center for Environmental Technology and Management, The Hong Kong Polytechnic University, Hong Kong, China
d Department of Science and Environmental Studies and Centre for Education for Environmental Sustainability, The Hong Kong Institute of Education, Hong Kong, China

10.1016/j.partic.2014.08.006

Volume 20, June 2015, Pages 134-140

Received 10 March 2014, Revised 12 August 2014, Accepted 28 August 2014, Available online 25 December 2014.

E-mail: chengyan@mail.xjtu.edu.cn

Highlights

• Real-time measurements of PM_2.5, PM_10–2.5 and BC were conducted over 12 months in a street canyon.

• PM_2.5 showed good correlations with traffic counts of private cars and double-deck buses.

• PM_2.5 and BC show similar diurnal variations with diesel-fueled vehicles.

• PM_10–2.5 showed good correlations with total traffic counts and wind speed during the test period.

Abstract

A continuous dichotomous beta gauge monitor was used to characterize the hourly content of PM_2.5, PM_10–2.5, 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_2.5, PM_10–2.5, and BC suggested that all species are related to traffic, with high concentrations on workdays and low concentrations over the weekends. PM_2.5 exhibited two comparable concentrations at 10:00–11:00 (63.4 μg/m³) and 17:00–18:00 (65.0 μg/m³) 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⁻¹, respectively. BC is emitted mainly by diesel-fueled vehicles and this showed the highest concentration (31.2 μg/m³) during the midday period (10:00–11:00 LT) on workdays. A poor correlation was found between PM_2.5 concentration and wind speed (R = 0.51, P-value > 0.001). In contrast, the concentration of PM_10–2.5 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).

Graphical abstract

Keywords

PM_2.5; PM_10–2.5; BC; Hong Kong; Urban street canyon

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