PROJECT SUMMARY/ABSTRACT
This project will compare indoor air quality at three underground subway stations in Philadelphia with the
corresponding aboveground urban locations as well as one suburban location. We found previously that PM
levels in Philadelphia subway stations can be up to five times higher than levels on an urban street. We will
assess effects of particulate matter (PM) from the various locations on lung epithelial cells (16HBE and primary
cells), assessing cytotoxicity, oxidative stress, and the cellular response pathways involving the antioxidant
response element (ARE) and the xenobiotic response element (XRE). A primary purpose is to assess the
contributions of various PM components to these cellular responses. In Aim 1, we will collect 102 total samples
from the various locations and determine to what extent levels of black carbon (BC), ultrafine particles (UFP),
and metals correlate with the cellular effects. Both BC and UFP have been associated with cellular oxidative
stress. Subway PM is particularly high in metals such as iron, copper, antimony and zinc, which come from the
rails, wheels, brake pads, and other parts of the trains, which have been correlated with oxidative stress and
ARE activation from other PM sources. In Aim 2, we will examine the role of soluble/chelatable metals compared
to metals in whole particles on the cellular effects, as well assess contributions from organic compounds on
these effects. As part of this work, we will probe the contributions of the XRE and ARE pathways to the cellular
effects by using siRNA against the relevant sensors/transcription factors, aryl hydrocarbon receptor (AhR) and
Nrf2, respectively. Dose response curves will be used to assess effects over a range of concentrations. Results
will help in understanding and ideally mitigating the health risks of subway air particles. We have assembled a
multidisciplinary team of researchers, including experts in air particulate analysis, cellular oxidative stress,
statistical analysis, and analytical metal analysis, and an inhalation toxicologist at the EPA. The project includes
ten undergraduate student positions working in three different departments at Villanova and two summer
positions at an EPA lab. Students will be primary drivers of the work, its interpretation, and presentation at
national conferences and authors on published work.