Table 4 Studies using in vitro-in vivo extrapolation for risk assessment of exposure to underground railway air pollution
First Author | Year | Location | [Airborne PM] (μg/m3) | PM Composition | Comparator PM | Model | Findings |
|---|---|---|---|---|---|---|---|
Kam [85] | 2011 (sampling May–August 2010) | Los Angeles, USA | PM10–2.5 = 11 ± 2; PM2.5 = 33 ± 1 | PM10–2.5: Fe = 27%; PM2.5: Fe = 32% | PM10–2.5 and PM2.5: overground train journey; ambient | Alveolar macrophage | Underground PM enriched in Fe, Mn, Cr, Co, Ni, Cu, Ba, Mo, Cd, Eu, especially in PM2.5–0.1. In terms of water-soluble elements, only Fe and Ba were higher in underground PM. For ROS generation, underground>overground>ambient, but difference small. |
Kam [86] | 2013 (sampling May–August 2010) | ″ | ″ | ″ | PM2.5: overground railway; HGV-heavy and HGV-light freeways; stop-go road | N/A | On the basis of airborne PAH concentration, lung cancer risk was: HGV-heavy road>HGV-freeway>stop-go road>overground railway>underground railway |
Lovett [87] | 2018 (sampling May–August 2010) | ″ | ″ | ″ | ″ | N/A | Extending [86] to also take metals into account, total hazard quotient from PM exposure greatest on the underground, mainly due to Cr(VI). Overground railway has lowest hazard. |
Cao [92] | 2017 (measurement March–August 2015) | Suzhou, China | PM2.5 regular hours: underground platform = 198 (range 86–351); carriages = 60 (45–121); PM2.5 rush hours: platform = 265 (112–365); carriages = 79 (75–145) | Not stated | 4 underground stations, 1 above ground station | N/A | PM2.5 underground stations>overground, especially in urban vs. green areas. Underground PM2.5 summer>spring. Underground exposure associated with 6390 DALYs = 375 premature deaths = 1% total deaths in the city. |