title: Evaluation of the effectiveness of air pollution control measures in Hong Kong.
abstract: From 2005 to 2013, volatile organic compounds (VOCs) and other trace gases were continuously measured at a suburban site in Hong Kong. The measurement data showed that the concentrations of most air pollutants decreased during these years. However, ozone (O3) and total non-methane hydrocarbon levels increased with the rate of 0.23 ± 0.03 and 0.34 ± 0.02 ppbv/year, respectively, pointing to the increasing severity of photochemical pollution in Hong Kong. The Hong Kong government has ongoing programs to improve air quality in Hong Kong, including a solvent program implemented during 2007-2011, and a diesel commercial vehicle (DCV) program since 2007. From before to after the solvent program, the sum of toluene, ethylbenzene and xylene isomers decreased continuously with an average rate of -99.1 ± 6.9 pptv/year, whereas the sum of ethene and propene increased by 48.2 ± 2.0 pptv/year from before to during the DCV program. Despite this, source apportionment results showed that VOCs emitted from diesel exhaust decreased at a rate of -304.5 ± 17.7 pptv/year, while solvent related VOCs decreased at a rate of -204.7 ± 39.7 pptv/year. The gasoline and liquefied petroleum gas vehicle emissions elevated by 1086 ± 34 pptv/year, and were responsible for the increases of ethene and propene. Overall, the simulated O3rate of increase was lowered from 0.39 ± 0.03 to 0.16 ± 0.05 ppbv/year by the solvent and DCV programs, because O3produced by solvent usage and diesel exhaust related VOCs decreased (p < 0.05) by 0.16 ± 0.01 and 0.05 ± 0.01 ppbv/year between 2005 and 2013, respectively. However, enhanced VOC emissions from gasoline and LPG vehicles accounted for most of the O3increment (0.09 ± 0.01 out of 0.16 ± 0.05 ppbv/year) in these years. To maintain a zero O3increment in 2020 relative to 2010, the lowest reduction ratio of VOCs/NOx was ∼1.5 under the NOx reduction of 20-30% which was based on the emission reduction plan for Pearl River Delta region in 2020.
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: X P
authors.initials: XP
authors.lastname: Lyu
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: L W
authors.initials: LW
authors.lastname: Zeng
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong. Electronic address: ceguohai@polyu.edu.hk.
authors.forename: H
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Chemistry, University of California at Irvine, CA, USA.
authors.forename: I J
authors.initials: IJ
authors.lastname: Simpson
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Ling
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Environmental Science, Murdoch University, Perth, Australia.
authors.forename: F
authors.initials: F
authors.lastname: Murray
authors.affiliation: Environmental Protection Department, Hong Kong.
authors.forename: P K K
authors.initials: PKK
authors.lastname: Louie
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, Perth, Australia.
authors.forename: S M
authors.initials: SM
authors.lastname: Saunders
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, Perth, Australia; Pacific Environment Limited, Perth, Australia.
authors.forename: S H M
authors.initials: SHM
authors.lastname: Lam
authors.affiliation: Department of Chemistry, University of California at Irvine, CA, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Blake
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000331:legislation & jurisprudence / Q000517:prevention & control*; D000475:Alkenes; D001555:Benzene Derivatives; D004784:Environmental Monitoring; D058735:Environmental Policy; D006723:Hong Kong; D006838:Hydrocarbons / Q000032:analysis; D010126:Ozone / Q000032:analysis; D045483:Rivers; D012997:Solvents; D014050:Toluene / Q000032:analysis; D001335:Vehicle Emissions / Q000032:analysis; D055549:Volatile Organic Compounds / Q000032:analysis
chemical_list: D000393:Air Pollutants; D000475:Alkenes; D001555:Benzene Derivatives; D006838:Hydrocarbons; D012997:Solvents; D001335:Vehicle Emissions; D055549:Volatile Organic Compounds; D014050:Toluene; D010126:Ozone; C013658:propylene; C004912:ethylbenzene
keywords: Air pollution; Control measures; MCM; Ozone; Photochemical pollution