The concentration of TVOCs in public transportation in the spring and summer of 2018 was measured. Public transportation measured the concentration of TVOCs on six subway lines in Seoul, two lines of high-speed trains, and intercity buses. The measurements were taken during the operation of each route of the surveyed public transportation from the origin to the destination. In addition, the measurement time was divided into the congestion time and the non-congestion time. In the spring of 2018, in the order of subway, train A, train B, and intercity buses, TVOC concentrations during the congestion time zone were 205.9 μg/m3, 121.3 μg/m3, 171.1 μg/m3, and 88.7 μg/m3, respectively. During the non-congestion time zone, the concentrations were 177.2 μg/m3, 108.8 μg/ m3, 118.2 μg/m3, and 126.1 μg/m3, respectively. In the summer of 2018, TVOC concentrations in the order of the aforementioned transportation modes during the congestion time zone were 169.8 μg/m3, 175.8 μg/m3, 78.0 μg/ m3, and 185.3 μg/m3, respectively. During the non-congestion time zone, the concentrations were 210.8 μg/m3, 116.1 μg/m3, and 162.7 μg/m3, respectively. An analysis of BTEX concentration among VOCs in public transportation in descending order were followed by toluene > xylene > ethylbenzene > benzene. Toluene, which has the highest concentration among the BTEX compounds, was found to be 12.86 μg/m3 to 91.41 μg/m3 during spring congestion time and 7.10 μg/m3 to 39.52 μg/m3 during non-congestion time. During the summer congestion time, the concentration was 6.68 μg/m3 to 249.48 μg/m3 and 13.23 μg/m3 to 214.5 μg/m3 during the non-congestion time. The concentration of benzene was mostly less than 5 μg/m3 in transportation. Particularly in the case of toluene, the concentration is significantly higher than that of other VOCs. Accordingly, further study of toluene exposure hazards will be needed. Five percent of the surveyed TVOC concentrations exceeded the recommended indoor air quality standard of 500 μg/m3, and all 13 cases representing this percentage were found in the subway. In addition, nine of the 13 cases that exceeded the recommended standard were measured during congestion time. Therefore, VOCs in public transportation vehicles during congestion time need to be managed.

The purpose of this study is to provision the standard method for ensuring the reliability of measuring indoor air quality in public transportation. The objective is to determine the difference in the measured concentration values according to various conditions. These variables include measurement conditions, measurement equipment, measurement points, and measurement time. The value differences are determined by measuring the PM10 and CO2 concentration of subways, and express buses and trains, which are targets of indoor air quality management. The concentration of CO2 was measured by the NDIR method and that of PM10 was measured by the gravimetric method and light-scattering method. Statistically, the results of the concentration comparison according to the measurement points of the public transportation modes were not significantly different (p > 0.05), and it is deemed that the concentration is not affected by the measurement points. In terms of the concentration analysis results according to the measurement method, there was a difference of the concentration between the gravimetric and light scattering method. In the case of the light scattering method, the concentration differed depending on whether it was corrected with standard particles in the laboratory environment.

In this study, we measured the concentration of total volatile organic compounds (TVOCs) in four different seasons from 2016 to 2017 in order to determine seasonal variation of indoor air quality in relation to public transportation modes (subways, trains, and express buses). The measurement was carried out both during rush hour when traffic was congested as well as during non-rush hour when traffic was not congested. Effects by season, degree of congestion, and characteristics of public transportation were analyzed on the basis of 295 items of data during the periods of congestion and 295 items of data during the periods of non-congestion. The average TVOCs concentration in winter was the highest with 226.4 μg/m 3 . The average TVOCs concentration on an express bus was the highest with a seasonal average of 142.3 μg/m 3 . The TVOCs concentration in the period of congested traffic was higher than in the period of non-congested traffic for all public transportation modes. For the average TVOCs concentration by season and transportation, there was no data that exceeded the guidelines regarding maintaining indoor air quality. However, 2.5% of all sample measured data (TVOCs) exceeded the guidelines regarding maintaining indoor air quality. Therefore, the continuous monitoring of public transport vehicles is required.

This study investigates the indoor air quality conditions of the total of 52 buses depend on seasons, time and others. We evaluated the CO₂and PM10, the controlled parameters in express buses by Ministry of Environment and VOCs and HCHO, the non-controlled parameters. The CO₂concentration during peak commute times was 38.5% in summer and 15.4% in autumn, which are higher than the normal. But, PM10 concentration was influenced by the outside air not number of passengers. The concentration of VOCs were not related with other parameters such as number of passengers, seasons, and driving time. And then, the formaldehyde concentration was not related with seasons as it showed little difference between summer and autumn.

FOSS(free and open source software)는 라이선스의 제약 없이 자유롭게 소스코드를 재사용하거나 수정 및 배포할 수 있는 소프트웨어로서, 정보시스템 구축의 새로운 대안으로 자리잡아가고 있다. 최근 GIS의 컴퓨팅 환경이 웹으로 확장되면서 FOSS를 활용하여 공간데이터를 공유하거나 시각화하기 위한 시도들이 이루어지고 있다. 기존의 연구들을 통해 볼 때, 웹GIS에서 FOSS 애플리케이션들은 환경 및 생태 정보 제공을 위한 지도서비스가 주를 이루며 분석지향적인 사례는 매우 드물다. 또한 공간 DBMS(database management system), GIS툴, 통계패키지 등의 FOSS가 개별적으로 웹GIS에 활용되어 왔으나, 개방성과 재사용성이 우수한 이들 FOSS를 커플링(coupling)하면 공간자료의 공유, 시각화에서 더 나아가 공간데이터의 통계분석을 지원하는 웹GIS가 구축 가능할 것이다. 이에 본 연구에서는 웹 환경에서 DBMS, GIS툴 및 통계패키지를 커플링하는 브로커리지(brokerage) 모듈을 개발하고, 이를 이용하여 공간자료의 저장, 질의, 처리 및 통계분석을 수행하며 그 결과를 시각화하는 FOSS 기반의 웹GIS 프레임워크를 제시하고자 한다. 공간 DBMS로는 래스터와 벡터가 모두 지원되는 PostGIS을 이용하였고, 공간데이터 프로세싱에는 GRASS, 통계분석에는 R, 시각화를 위한 지오브라우저로는 Google Maps와 Google Earth를 사용하였다. 이러한 FOSS들의 커플링을 위한 브로커리지 모듈은 운영체제 독립적인 Java 언어로 구현되었으며, API(application programming interface)를 통해 JSP(Java Server Pages)에서 참조하여 웹 인터페이스를 구성하도록 하였다. 본 시스템에 대한 테스트에서는, 남한지역의 NDVI(normalized difference vegetation index)와 환경요소 간의 회귀분석을 수행하는 프로토타입을 통해 공간데이터의 공유, 프로세싱, 시각화, 분석에 있어서의 가용성이 검토되었다.