TY - JOUR
T1 - Continuous effectiveness of replacing catalytic converters on liquified petroleum gas-fueled vehicles in Hong Kong
AU - Yao, Dawen
AU - Lyu, Xiaopu
AU - Murray, Frank
AU - Morawska, Lidia
AU - Yu, Wang
AU - Wang, Jiaying
AU - Guo, Hai
N1 - Funding Information:
We wish to thank the Environmental Protection Department of the Hong Kong Special Administrative Region for supplying the data for this study. This study is supported by the National Key R&D Program of China via grant No. 2017YFC0212001 , Research Grants Council of the Hong Kong Special Administrative Region Government via grant PolyU 152052/16E and CRF/C5004-15E , the Public Policy Research Funding Scheme from Policy Innovation and Co-ordination Office of the Hong Kong Special Administrative Region Government (Project Number: 2017.A6.094.17D), and the Hong Kong Polytechnic University PhD scholarships (Project Number: RJKD).
Funding Information:
We wish to thank the Environmental Protection Department of the Hong Kong Special Administrative Region for supplying the data for this study. This study is supported by the National Key R&D Program of China via grant No. 2017YFC0212001, Research Grants Council of the Hong Kong Special Administrative Region Government via grant PolyU 152052/16E and CRF/C5004-15E, the Public Policy Research Funding Scheme from Policy Innovation and Co-ordination Office of the Hong Kong Special Administrative Region Government (Project Number: 2017.A6.094.17D), and the Hong Kong Polytechnic University PhD scholarships (Project Number: RJKD).
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/1
Y1 - 2019/1
N2 - To mitigate the concentrations of air pollutants in the atmosphere, an intervention program of replacing the converters of liquefied petroleum gas (LPG) fueled vehicles was implemented by the Hong Kong government between October 2013 and April 2014. Data of ambient volatile organic compounds (VOCs) and other trace gases continuously monitored from September 2012 to April 2017 at a roadside site were used to evaluate the continuous effectiveness of the replaced catalytic converters on the reduction of air pollutants. The measurement data showed that LPG-related VOCs (propane and n/i-butanes) and several trace gases (CO, NO and NO2) decreased significantly from before to after the program (p < 0.01). To further assess the efficiency of the program, five periods covering before the program, during the program, 1st year after the program, 2nd year after the program and 3rd year after the program were categorized. The values of propane and n/i-butanes decreased from Period-1 (before the program) to Period-2 (during the program), and from Period-2 to Periods 3–5 (after the program) (p < 0.01). In addition, the reduction rates of propane and n/i-butanes remained high and constant in Periods 3–5, suggesting that either had the vehicle owners themselves routinely replaced the converters at suitable interval afterwards, or were their vehicles caught by a remote sensing program checking excessive emissions. Source apportionment analysis indicated that LPG-fueled vehicular emissions were the top contributor to ambient VOCs in the roadside environment while the VOCs emitted from LPG-fueled vehicles indeed decreased at a rate of 4.21 ± 2.38 ppbv/year (average ± 95% confidence interval) from Period-1 to Period-5 (p < 0.01). Furthermore, the photochemical box model simulations revealed that the net negative contribution of VOCs and NOx emitted from LPG-fueled vehicles to O3 production strengthened at a rate of 1.9 × 10−2 pptv/day from Period-1 to Period-5 (p < 0.01). The findings proved the continuous effectiveness of the intervention program, and are of help to future control strategies in Hong Kong.
AB - To mitigate the concentrations of air pollutants in the atmosphere, an intervention program of replacing the converters of liquefied petroleum gas (LPG) fueled vehicles was implemented by the Hong Kong government between October 2013 and April 2014. Data of ambient volatile organic compounds (VOCs) and other trace gases continuously monitored from September 2012 to April 2017 at a roadside site were used to evaluate the continuous effectiveness of the replaced catalytic converters on the reduction of air pollutants. The measurement data showed that LPG-related VOCs (propane and n/i-butanes) and several trace gases (CO, NO and NO2) decreased significantly from before to after the program (p < 0.01). To further assess the efficiency of the program, five periods covering before the program, during the program, 1st year after the program, 2nd year after the program and 3rd year after the program were categorized. The values of propane and n/i-butanes decreased from Period-1 (before the program) to Period-2 (during the program), and from Period-2 to Periods 3–5 (after the program) (p < 0.01). In addition, the reduction rates of propane and n/i-butanes remained high and constant in Periods 3–5, suggesting that either had the vehicle owners themselves routinely replaced the converters at suitable interval afterwards, or were their vehicles caught by a remote sensing program checking excessive emissions. Source apportionment analysis indicated that LPG-fueled vehicular emissions were the top contributor to ambient VOCs in the roadside environment while the VOCs emitted from LPG-fueled vehicles indeed decreased at a rate of 4.21 ± 2.38 ppbv/year (average ± 95% confidence interval) from Period-1 to Period-5 (p < 0.01). Furthermore, the photochemical box model simulations revealed that the net negative contribution of VOCs and NOx emitted from LPG-fueled vehicles to O3 production strengthened at a rate of 1.9 × 10−2 pptv/day from Period-1 to Period-5 (p < 0.01). The findings proved the continuous effectiveness of the intervention program, and are of help to future control strategies in Hong Kong.
KW - Catalytic converter
KW - Continuous effectiveness
KW - LPG-fueled vehicle
KW - O3
KW - VOCs
UR - http://www.scopus.com/inward/record.url?scp=85051665998&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2018.08.191
DO - 10.1016/j.scitotenv.2018.08.191
M3 - Journal article
C2 - 30138883
AN - SCOPUS:85051665998
SN - 0048-9697
VL - 648
SP - 830
EP - 838
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -