Evaluation of indoor particulate matter control based on health risks and oxidative potential in a metro station

Abstract

Particulate matter (PM) from different sources exhibits diverse chemical and physical characteristics, and it is an essential carrier of toxic chemicals. Ignoring PM properties is inappropriate for indoor air quality (IAQ) control in places with internal sources, such as metro stations. PM control measures aimed at health protection should be established based on PM health effects. The current PM control limit for metro stations may be insufficient for health protection. It is important to find a method that comprehensively evaluates PM features to set PM exposure limits. This study evaluated the health risks induced by chemical components and the oxidative potential of PM in the Tianjinzhan metro station. A PM control strategy was suggested based on health effect analysis. PM on the platform had notable underlying adverse health effects. An in-depth toxicology analysis was suggested to assess the high Ba and Mn concentrations in PM. The risk from Cr raised concern regarding the potential for carcinogenicity. As a potential composite index, the dithiothreitol (DTT) activity may be appropriate to evaluate the general adverse health effects caused by PM. The DTT activity of the platform was 3.3–5.4 times that of the ventilation shaft. Removing a unit mass of PM1 in the station hall would produce more health benefits than the removal of a unit mass of PM2.5. However, the DTT results indicated that control strategies on the platform should first focus on PM2.5, which would achieve the same protection effect as that when the PM1 mass concentration is decreased by the same level. A revision of the PM2.5 control limit for China metro stations was recommended to control oxidative potential on the platform.