Oxidative Potential and Inflammatory Impacts of Source Apportioned Ambient Air Pollution in Beijing

Abstract

Air pollution exposure is associated with a range of adverse health impacts. Knowledge of the chemical components and sources of air pollution most responsible for these health effects could lead to an improved understanding of the mechanisms of such effects and more targeted risk reduction strategies. We measured daily ambient fine particulate matter (<2.5 μm in aerodynamic diameter; PM2.5) for 2 months in peri-urban and central Beijing, and assessed the contribution of its chemical components to the oxidative potential of ambient air pollution using the dithiothreitol (DTT) assay. The composition data were applied to a multivariate source apportionment model to determine the PM contributions of six sources or factors: a zinc factor, an aluminum factor, a lead point factor, a secondary source (e.g., SO4(2-), NO3(2-)), an iron source, and a soil dust source. Finally, we assessed the relationship between reactive oxygen species (ROS) activity-related PM sources and inflammatory responses in human bronchial epithelial cells. In peri-urban Beijing, the soil dust source accounted for the largest fraction (47%) of measured ROS variability. In central Beijing, a secondary source explained the greatest fraction (29%) of measured ROS variability. The ROS activities of PM collected in central Beijing were exponentially associated with in vivo inflammatory responses in epithelial cells (R2=0.65-0.89). We also observed a high correlation between three ROS-related PM sources (a lead point factor, a zinc factor, and a secondary source) and expression of an inflammatory marker (r=0.45-0.80). Our results suggest large differences in the contribution of different PM sources to ROS variability at the central versus peri-urban study sites in Beijing and that secondary sources may play an important role in PM2.5-related oxidative potential and inflammatory health impacts.

In vitro and in vivo toxicity of urban and rural particulate matter from California

“…Further, in our previous work the correlations between trace elemental concentrations and ROS response were similar in magnitude to that presented in the current manuscript and it appeared that stronger correlations were seen with %PMNs. Similar correlation coefficients were seen in a previous study (Liu et al 2014). …”

Association Between Environmental Particulate Matter and Carpal Tunnel Syndrome in Patients Undergoing Hemodialysis

“…Adults exposed to diesel exhaust including 300 μg PM 2.5 /m 3 for 120 min also had an increased serum concentration of TNF-α [21]. Ambient air pollution evaluated by the level of PM 2.5 in Beijing also induced higher levels of TNF-α expression in participants’ bronchial epithelial cells [22]. PM 2.5 might be associated with CTS in HD patients by inducing TNF-α based on these in vivo and in vitro studies.…”

Maternal exposure to carbon monoxide and fine particulate matter during pregnancy in an urban Tanzanian cohort

“…Personal exposures are also likely affected by non‐combustion sources such as traffic, as has been described in other work (Zhou et al., ). From the few source apportionment studies available from settings where solid fuel use is common, it appears that while solid fuels are important contributors to ambient air pollution and personal exposure, other sources contribute to the majority of daily exposures in urban settings (Liu et al., ; Zhou et al., ). Our findings together with these prior studies suggest that strategies to reduce personal exposure to air pollution in pregnancy may require more than individual level cooking interventions; this may be particularly relevant for urban populations.…”