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Characterizing Acute and Chronic Personal PM Exposure Levels for Detroit Adults Using a Nephelometer [platform]

Charles Rodes, Jonathan Thornburg, Jeremy Seagraves, Phil Lawless. RTI International, Research Triangle Park, NC 27709

Alan Vette, Carvin Stevens, and Ron Williams, U.S. EPA, Research Triangle Park, NC 27711

The Detroit Exposure and Aerosol Research Study (DEARS) design focused on characterizing residential exposures that can be linked to exposure pathways and local sources. To address PM exposures, parallel gravimetric PM2.5 collections (integrated to characterize chronic levels) were paired with portable MIE nephelometers in personal, indoor, and outdoor Detroit settings. The integrated collections are traceable to the health-based EPA PM2.5 and PM10 referee methods. The MIE aerosol collections were sized to respond to particles <2.5 m, calibrated against realistic challenge levels of ammonium nitrate rather than generic Arizona Test Dust, and adjusted for humidity bias. Pairing the MIE concentrations under real environmental conditions with paired integrated collections allowed for verification of the response calibrations.

This presentation will summarize the performance and data quality of the paired integrated and real-time devices, and briefly summarize the relationships between personal, indoor, and backyard integrated PM collections and central site data. For example, uncorrected MIE's over-estimated collocated personal gravimetric mass exposures for Season 5 (summer) on average by almost 90%.

The review will then address the increased insights gained by adding real-time (acute) data to integrated PM collections. These insights include review of selected real-time data with time-activity diaries to illustrate the activities and sources most like causing the greatest differences among exposure settings. Data will also be presented characterizing the magnitude and frequency of significant PM changes observed during personal, indoor, and ambient monitoring, and where possible, the locations and times-of-day where such events occurred. As expected, indoor step changes from strong sources such as cooking and smoking typically showed the greatest maximum values, often increasing by >100 g/m3 for 15 minute periods.

Although this work was reviewed by U.S. EPA and approved for publication, it may not necessarily reflect official Agency policy.

DEARS Home | Human Exposure & Atmospheric Sciences | Exposure Research

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