댿�학원_논��_세미나_리뷰_발표(화공,환경,대기,AQI)

Four sets of samples collected in tunnels, at platforms, near ticket offices, and outdoors were investigated.
For the samples collected in tunnels, Fe-containing particles predominate, with relative abundances of 75-91% for the four stations. The amounts of Fe-containing particles decrease as the distance of sampling locations from the tunnel increases.
In addition, samples collected at the platform in subway stations with platform screen doors (PSDs) that limit air mixing between the platform and the tunnel showed marked decreases in relative abundances of Fe-containing particles, clearly indicating that Fe-containing subway particles are generated in the tunnel.
PM10 mass concentration levels are the highest in the tunnels, becoming lower as the distance of sampling locations from the tunnel increases. The extent of the decrease in PM10 in stations with PSDs is also larger than that in stations without PSDs.
The results clearly indicate that Fe-containing particles originating in tunnels predominate in the indoor microenvironment of subway stations, resulting in high indoor PM10 levels, and that PSDs play a significant role in reducing Fe-containing particles at platforms and near ticket offices.

2. Experimental Section
In this work, subway particle samples were collected at four different locations of four under- ground subway stations in Seoul, namely the “Jegi”, “Chungmuro”, “Yangjae”, and “Seouldae” stations (the four stations are denoted as stations S1-S4, respectively), to identify local sources of PM in the subway.
In many of Seoul’s subway stations (stations S3 and S4 belong to them), PSDs (full-height barriers between the station floor and ceiling) are installed between the tunnel and the platform, that effectively limit air-mixing between the platform and the tunnel, and climate control within the stations can be improved as heating, ventilation, and air conditioning are more effective when the platform is physically isolated from the tunnel.
Sampling for single particle analysis was done using a 3-stage Dekati PM10 sampler on Feb. 10-12, Feb. 18-20, Feb. 24-26, and March 3-5, 2009 in stations S1-S4, respectively. For each station, sampling was done for three consecutive days, once a day (see Table 1 for sampling dates and times).
Daily PM10 mass concentrations for the same sampling days and locations were also measured using high volume PM10 samplers (TE-5000, Tisch Environmental, Inc., Ohio, USA) (Table 1).