The urban railway system is a convenient public transportation system, as it carries many people without increasing traffic congestion. However, air quality in urban railway environments is worse than ambient air quality due to the internal location of the source of air pollutants and the isolated space. In this paper, characteristics of particulate matter (PM) pollution in urban railway environments are described from the perspective of diurnal variation, chemical composition and source apportionment of PM. PM concentrations in concourse, platform, passenger cabin, and tunnel are summarized through an analysis of 34 journal articles published in Korea and overseas. This information will be helpful in developing effective policies to reduce PM pollution in urban railway environments.

Abstract
 1. 서 론
 2. 도시철도 환경에서 미세먼지 오염의 특징
  2.1 터널 내 미세먼지의 거동
  2.2 터널 내 미세먼지의 일변화
  2.3 미세먼지의 화학적 조성 및 오염원
 3. 도시철도 환경에서 미세먼지 농도 수준
  3.1 국내외 관련 연구
  3.2 지하역사 내 미세먼지 농도 수준
  3.3 객실 내 미세먼지 농도 수준
  3.4 터널 내 미세먼지 농도 수준
 4. 제 언
 References

• 김종범(충남연구원 서해안기후환경연구소) | Jong Bum Kim (Seohaean Research Institute, ChungNam Institute)
• 이승복(한국과학기술연구원 환경복지연구단) | Seung-Bok Lee (Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST))
• 배귀남(한국과학기술연구원 미세먼지사업단) | Gwi-Nam Bae (Center for Particulate Air Pollution and Health, Korea Institute of Science and Technology (KIST)) Corresponding author