AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Metal Concentrations in Fine Particulate Matter from the Ground-Level Light Rail System in Denver Metro
BENTON CARTLEDGE, Brian Majestic, University of Denver
Abstract Number: 401 Working Group: Urban Aerosols
Abstract Many studies have linked increased concentrations of airborne heavy metals, such as chromium, manganese, and iron, to subway systems. These higher concentrations have been investigated to determine potential health risks to personnel who operate or almost exclusively ride the subway. Health studies have shown that the inhalation of submicron particles with increased metal concentrations can lead to increased redox activity at the cellular level and heightened occurrences of cancers and respiratory illnesses. Very few studies have been performed examining the effects of ground-level, outdoor light rail transit systems. The current study focused on the light rail system in Denver, Colorado. Size-segregated air samples were collected using Sioutas personal cascade impactor samplers (PCIS) at three locations around downtown Denver. The first location was the background site located away from the light rail lines. The second site was one meter from the tracks as all five light rail lines entered and exited the downtown area. The third site was onboard the light rail trains. Samples were collected onboard all five lines each day. Outside samples were collected for 42 hours a week while onboard samples were collected 36 hours a week. Four sets of samples were collected from January 24 to February 16, 2012. Metal concentrations were determined via a strong acid digest in a microwave digestion system and analysis via inductively coupled plasma mass spectrometry (ICP-MS). Soluble iron and iron speciation was also determined by extracting the samples in a buffer and measuring UV absorbance on a long pathlength capillary cell spectrometer. Results suggest that higher metal concentrations (especially steel components) are found near and onboard the train. Soluble iron was determined to be present mostly as Fe(II). While these levels may not be as high as in subways, metal concentrations could still pose serious health risks.