Characteristics of In-cabin PM2.5 Concentration in Seoul Metro Line Number 2 in Autumn

서울시 지하철 2호선의 가을철 객실 PM2.5 농도의 특성

  • Shin, Hyerin (Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University) ;
  • Jung, Hyunhee (Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University) ;
  • Lee, Kiyoung (Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University)
  • 신혜린 (서울대학교 보건대학원 환경보건학과) ;
  • 정현희 (서울대학교 보건대학원 환경보건학과) ;
  • 이기영 (서울대학교 보건대학원 환경보건학과)
  • Received : 2019.03.29
  • Accepted : 2019.04.20
  • Published : 2019.04.30


Objectives: Subway is one of the most common transportation modes in Seoul, Korea. The objectives of this study were to determine characteristics of in-cabin $PM_{2.5}$ concentration in Seoul Metro Line Number 2 and to identify factors of the $PM_{2.5}$ concentration. Methods: In-cabin $PM_{2.5}$ concentrations in Seoul Metro Line Number 2 were measured using real-time monitors and the factors affecting $PM_{2.5}$ concentration in cabin were observed. Linear regression analysis of in-cabin $PM_{2.5}$ concentration and indoor/outdoor (I/O) ratio were performed. Results: In-cabin $PM_{2.5}$ concentration was associated with the in-cabin $PM_{2.5}$ concentration in previous station. In-cabin $PM_{2.5}$ concentration was correlated with ambient $PM_{2.5}$ concentration and associated with underground station with control of the in-cabin $PM_{2.5}$ concentration in previous station. I/O ratio increased as the number of passengers increased and when passing through the underground station with control of I/O ratio in previous station. Conclusion: In-cabin $PM_{2.5}$ concentration was affected by ambient $PM_{2.5}$ concentration. Therefore, management of in-cabin $PM_{2.5}$ concentrations should be based on outdoor air quality.


Supported by : 한국연구재단


  1. Seoul Metropolitan Government. Traffic card data '16 Seoul public transportation status reduced by passengers for two consecutive years. Available: [accessed 31 December 2018].
  2. Seoul Metropolitan Government. Seoul subway congestion statistics. Available: [accessed 2 January 2019].
  3. The Korea Transport Institute. Korea transport database. Available: [accessed 2 January 2019].
  4. Kong S, Bae H, Hong S, Park H. A study on the health impact and management policy of $PM_{2.5}$ in Korea (II), Korea Environment Institute; 2013.
  5. Kwag H, Jin K, Kim W, Yang W, Choi S, Part D. Evaluation on air quality inside subway driver cabin by monitoring PM, $CO_2$, and CO levels. Korean Journal of Environmental Health. 2005; 31(5): 379-386.
  6. Kim Y, Hong S, Jeon J. Investigation of indoor air quality of public transportation system in Seoul city. Korean Journal of Environmental Health. 1994; 3:28-38.
  7. Lee T, Lim H, Park D, Kim D. Concentration and properties of particulate matters ($PM_{10}$ and $PM_{2.5}$) in the Seoul metropolitan. Journal of Korean Society for Atmospheric Environment. 2015; 31(2): 164-172.
  8. Lee E, Lee T, Park M, Park D, Kim D. Characteristics of particulate matter concentration and classification of contamination patterns in the Seoul metropolitan subway tunnels. Journal of Korean Society for Atmospheric Environment. 2017; 33(6): 593-604.
  9. Roh Y, Park W, Lee C, Kim Y, Park D, Kim S. A study of PM levels in subway passenger cabins in Seoul metropolitan area. Journal of Korean Society of Occupational Environmental Hygiene. 2007; 17(1): 13-20.
  10. Kim J, Woo S, Kim C, Lim H, Hwang M, Yoon H, et al. Characteristics of particulate pollution in a cabin of operating urban railway. Journal of Korean Society for Urban Railway. 2017; 5(4): 1015-1026.
  11. Lee K, Hahn EJ, Riker C, Head S, Seithers P. Immediate impact of smoke-free laws on indoor air quality. Southern Medical Journal. 2007; 100(9): 885-889.
  12. Borgini A, Tittarelli A, Ricci C, Bertoldi M, De Seager E, Crosignani P. Personal exposure to $PM_{2.5}$ among high-school students in Milan and background measurement: the EuroLifeNet study. Atmospheric Environment. 2011; 45: 4147-4151.
  13. Semple S, Green DA, McAlpine G, Cowie H, Seaton A. Exposure to particulate matter on an Indian stone-crushing site. Occupational Environmental Medicine. 2008; 65: 300-305.
  14. Yun D, Kim M, Lee J, Kim B, Lee D, Lee S, et al. Correction factors for outdoor concentrations of $PM_{2.5}$ measured with portable real-time monitors compared with gravimetric methods: results from South Korea. Journal of Environmental Science International. 2015; 24(12): 1559-1567.
  15. Dacunto PJ, Cheng KC, Acevedo-Bolton V, Jiang RT, Klepeis NE, Repace JL, et al. Real-time particle monitor calibration factors and $PM_{2.5}$ emission factors for multiple indoor sources. Environmental Science Processes & Impacts. 2013; 15: 1511-1519.
  16. Arnio P, Uli-Tuomi T, Kousa A, Makela T, Hirsikko A, Hameri K, et al. The concentration and composition of and exposure to fine particles (PM2.5) in the Helsinki subway system. Atmospheric Environment. 2005; 39: 5059-5066.
  17. Wang X, Gao O. Exposure to fine particle mass and number concentrations in urban transportation environments of New York City. Transport and Environment. 2011; 16(5): 384-391.
  18. Cheng YH, Liu ZS, Yan JW. Comparisons of $PM_{10}$, $PM_{2.5}$, Particle Number, and $CO_2$ levels inside metro trains traveling in underground tunnels and on elevated tracks. Aerosol and Air Quality Research. 2012; 12: 879-897.
  19. Park D, Lee T, Hwang D, Jung W, Lee Y, Cho K, et al. Identification of the sources of PM10 in a subway tunnel using positive matrix factorization. Journal of Air Waste Management Association. 2014; 64: 1360-1367.
  20. Seoulmetro cyberstation. Available: https://smss. [accessed 25 April 2019].