title: A multivariate study for characterizing particulate matter (PM(10), PM(2.5), and PM(1)) in Seoul metropolitan subway stations, Korea.
abstract: Given that around eight million commuters use the Seoul Metropolitan Subway (SMS) each day, the indoor air quality (IAQ) of its stations has attracted much public attention. We have monitored the concentration of particulate matters (PMx) (i.e., PM10, PM2.5, and PM1) in six major transfer stations per minute for three weeks during the summer, autumn, and winter in 2014 and 2015. The data were analyzed to investigate the relationship between PMx concentration and multivariate environmental factors using statistical methods. The average PM concentration observed was approximately two or three times higher than outdoor PM10 concentration, showing similar temporal patterns at concourses and platforms. This implies that outdoor PM10 is the most significant factor in controlling indoor PM concentration. In addition, the station depth and number of trains passing through stations were found to be additional influences on PMx. Principal component analysis (PCA) and self-organizing map (SOM) were employed, through which we found that the number of trains influences PM concentration in the vicinity of platforms only, and PMx hotspots were determined. This study identifies the external and internal factors affecting PMx characteristics in six SMS stations, which can assist in the development of effective IAQ management plans to improve public health.
authors.affiliation: Transportation Environmental Research Team, Korea Railroad Research Institute, Uiwang-si 437-757, Republic of Korea.
authors.forename: Soon-Bark
authors.initials: SB
authors.lastname: Kwon
authors.affiliation: Transportation Environmental Research Team, Korea Railroad Research Institute, Uiwang-si 437-757, Republic of Korea.
authors.forename: Wootae
authors.initials: W
authors.lastname: Jeong
authors.affiliation: Transportation Environmental Research Team, Korea Railroad Research Institute, Uiwang-si 437-757, Republic of Korea.
authors.forename: Duckshin
authors.initials: D
authors.lastname: Park
authors.affiliation: Department of Environmental Engineering, Seoul National University of Science and Technology, Seoul 143-715, Republic of Korea.
authors.forename: Ki-Tae
authors.initials: KT
authors.lastname: Kim
authors.affiliation: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Korea. Electronic address: khcho@unist.ac.kr.
authors.forename: Kyung Hwa
authors.initials: KH
authors.lastname: Cho
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D002245:Carbon Dioxide / Q000737:chemistry; D004784:Environmental Monitoring; D015999:Multivariate Analysis; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D025341:Principal Component Analysis; D011890:Railroads; D056910:Republic of Korea; D066106:Seoul; D013696:Temperature; D014887:Weather
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D002245:Carbon Dioxide
keywords: Indoor air quality (IAQ); Particulate matter (PM); Principal Component Analysis (PCA); Self-Organizing Map (SOM); Seoul metropolitan subway (SMS)