Exploration of air particulate matter concentration on underground railway platforms and in train compartments in China and Europe

Recent studies have shown that the concentration of air particulate matter (PM10, PM2.5 and PM1) on underground railway platforms and in train compartments is much higher than the background concentration of urban particulate matter. Since the air in the underground railway system often contains more heavy metal particles, its biological toxicity is heightened. This paper compares the concentration and composition of the particulate matter in the underground railway systems in China and Europe based on the literature in recent years. Affected by the background concentration of urban particulate matter, the density of pedestrian and traffic flow, and the air purification measures, the concentration of particulate matter on underground railway platforms in China is generally higher than that in Europe, while the concentration of particulate matter in train compartments is at the same level. The composition of particulate matter on underground railway platforms in Chinese and foreign cities is similar, mainly containing heavy metals. The authors conclude from the literature and own experience that using a light scattering particle sampler without field gravimetric correction in the underground railway system may cause the inaccuracy of the measured values. It is suggested to formulate underground railway environmental testing standards and standardize testing methods and instruments, so as to further improve the air environment of the underground railway system.