Field Performance Evaluation of the Cooper Environmental Services Ambient Metals Monitor (Xact 620) for Near-Real Time PM10 Metals Monitoring

VARUN YADAV (1), Jay Turner (1), Krag Petterson (2), John Cooper (2)

(1) Washington University in St. Louis, (2) Cooper Environmental Services

     Abstract Number: 788
     Last modified: May 14, 2010

Abstract
The Cooper Environmental Services (CES) Ambient Metals Monitor (Xact 620) is designed for near-real time monitoring of ambient PM10 metals. This instrument features ambient particulate matter collection onto a filter tape for a user-defined sampling period. The filter tape is subsequently advanced to transfer the deposit into an analysis chamber where the elemental mass loadings are quantified by x-ray fluorescence (XRF). Simultaneous collection of a new deposit while the previous deposit is being analyzed provides a continuous stream of elemental data at the user-defined sampling time base.

A field study conducted in the St. Louis (MO-IL) metropolitan area from December 2008 to July 2009 featured six one-month deployments of a Xact 620 operating on a two-hour time base. Since August 2009 the instrument has been deployed near a large primary lead smelter in Herculaneum (MO) and is operating on a one-hour time base. In both cases, 18-to-24 hour integrated PM10 samples were collected on quartz filters using high-volume samplers and on Teflon filters using low-volume samplers. The Teflon filters were analyzed in the laboratory by XRF and both the quartz and Teflon filters were extracted and analyzed by ICP-MS. Furthermore, two Xact instruments were collocated for the month of August 2009 in Herculaneum. These data were used to determine performance metrics for the Xact including accuracy relative to conventional laboratory methods, collocated precision, and practical detection limits. This presentation will summarize the key results and their implications to using the data in applications such as receptor modeling.