AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Development of Near Continuous Sampling Methods for On Line Measurement of Chemical and Toxicological Properties of Size Fractionated PM
PAYAM PAKBIN, Constantinos Sioutas, Nancy Daher, Dongbin Wang, University of Southern California
Abstract Number: 222 Working Group: Instrumentation and Methods
Abstract Since PM components driving toxicity have diverse temporal variation and spatial distribution in the atmosphere, ambient measurements in high time resolution become critical to identify the toxicologically relevant PM species and further refine our understanding of atmospheric processes regulating their chemistry. Conventional quantitative analysis of PM chemical composition and toxicological properties is typically performed off-line, on particles collected on filter substrates, followed by extraction. In order to overcome the limitations of conventional sampling methodology a versatile online analyzer is being developed to allow hourly in-situ measurement of size-fractionated ambient aerosol trace elements and metals, water soluble organic carbon and offering great flexibility for other PM chemistry measurement. The toxicological significance of these chemistries will be established by concurrent macrophage-based ROS measurements.
The field evaluation of the sample collection module was conducted to demonstrate its adaptability and versatility for potential applications in long-term air quality monitoring with high resolution (i.e. hourly) of temporal variation of health relevant PM species. The chemical and oxidative characteristics of concentration-enriched PM2.5 samples simultaneously collected by filters, and the inertial impactor designed for the online sampler are compared. The deployment of these tools with on-line sampling and analysis methods will avoid artifacts associated with collection of PM on filter and impactor substrates and will allow the investigation of temporal changes in PM components and chemistry that is expected to change with sources, atmospheric aging and redox cycling.