In Korea researcher found that composition of PM size fraction was highly influenced by the air ventilation rate, which is related to the depth of the subway station.,
Indoor PMx increased with outdoor PM10, and
the ratio of PM1 to PM10 exhibited higher levels at concourses than platforms, especially during the winter.,
Both PM10 and CO2 concentrations were increased in the order of non-operation hours, normal-operating hours, and rush hour.,
The number of trains in operation was associated with the PM10 concentration at platforms.
Commuters of the subway line are exposed to greater PM concentrations than commuters of the light-rail line by almost two-fold.,Regression analysis showed that the light-rail line is heavily influenced by ambient PM levels and its particulate pollutants originate from local sources, such as vehicular emissions and road dust. The subway line is less influenced by ambient PM levels and has an additional source of airborne particulate pollution that is generated from the daily operation of trains.,PM2.5 and PM10 between train and stations reveal that PM from stations is the main source of PM inside trains.