PM2.5 Morphology and Speciation Analysis of BAM Tape During Wildfire Smoke Events

Kelly Cheng, ZHONG-MIN WANG, Jeff Wagner, Kazukiyo Kumagai, California Department of Public Health

     Abstract Number: 201
     Working Group: Instrumentation and Methods

Abstract
The beta attenuation monitor (BAM) is now a widely used Federal Equivalent Method to continuously measure particulate matter (PM) concentrations at most regulatory stations worldwide to meet federal and state monitoring requirements. In addition to monitoring PM concentration, characterization of the ambient PM elemental profile for the samples collected on glass fiber filters would provide meaningful chemical speciation of air pollution exposures.

This study describes the development of a sample extraction process and analytical method to analyze the particle morphology and element profile from the collected BAM tape for PM2.5. The key aspect for this method development is the minimization of the background interferences in BAM filters. In this study, the BAM filter tape samples collected during California wildfire smoke events in fall 2023 were used to develop the sample preparation method, and those samples were further characterized by ICP-MS and SEM-EDX to yield their particle morphology and chemical composition information. The analyses indicate that the BAM filters had enriched concentrations of chromium, manganese, and copper after blank subtraction during the wildfire smoke events.

The development of the method can potentially extend the capabilities of BAM PM regulatory monitors to further particle morphology and chemical speciation analysis of outdoor air exposures.