title: Relationship between rooftop and on-road concentrations of traffic-related pollutants in a busy street canyon: Ambient wind effects.
abstract: Rooftop and on-road measurements of O3, NO2, NOx, and CO concentrations were conducted to investigate the relationship between rooftop and on-road concentrations in a busy and shallow street canyon with an aspect ratio of ∼0.3 in Seoul, Republic of Korea, from 15 April to 1 May 2014. The median road-to-roof concentration ratios, correlation coefficients between rooftop and on-road concentrations, and temporal variations of rooftop and on-road concentrations are analyzed according to the rooftop wind directions which are two cross-canyon and two along-canyon directions. The analysis results indicate that the relationship is strong when the rooftop is situated on the downwind side rather than on the upwind side. Relative to the cross-canyon wind directions, one of the along-canyon wind directions can more enhance the relationship. A conceptual framework is proposed to explain the effect of ambient wind direction on the relationship between rooftop and on-road concentrations in a street canyon.
authors.affiliation: School of Earth and Environmental Sciences, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea; Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136-791, Republic of Korea.
authors.forename: Kyung-Hwan
authors.initials: KH
authors.lastname: Kwak
authors.affiliation: Department of Atmospheric Science, Kongju National University, Gongju, Chungcheongnam-do 314-701, Republic of Korea.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Lee
authors.affiliation: School of Earth and Environmental Sciences, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors.forename: Jaemyeong Mango
authors.initials: JM
authors.lastname: Seo
authors.affiliation: School of Earth and Environmental Sciences, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea; Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA.
authors.forename: Seung-Bu
authors.initials: SB
authors.lastname: Park
authors.affiliation: School of Earth and Environmental Sciences, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea. Electronic address: jjbaik@snu.ac.kr.
authors.forename: Jong-Jin
authors.initials: JJ
authors.lastname: Baik
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D015386:Hazardous Substances / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis*; D056910:Republic of Korea; D063809:Satellite Imagery; D012621:Seasons; D001335:Vehicle Emissions / Q000032:analysis*; D014919:Wind
chemical_list: D000393:Air Pollutants; D015386:Hazardous Substances; D052638:Particulate Matter; D001335:Vehicle Emissions
keywords: Ambient wind direction; Busy street canyon; On-road measurement; Rooftop measurement; Traffic-related pollutants