Fine Particulate Organic Material at Meadview During the Project MOHAVE Summer Intensive Study

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Analytical Chemistry

Background:

• Atmospheric fine particulate organic material influences air quality and climate.
• Accurate characterization of semi-volatile organic compounds (SVOCs) is crucial for understanding their atmospheric behavior.

Purpose of the Study:

• To assess the performance of two sampling systems (BOSS and BIG BOSS) for collecting atmospheric fine particulate organic material.
• To quantify the loss of SVOCs from particles during sampling and characterize these lost compounds.
• To determine the particle size distribution of organic material and specific SVOCs.

Main Methods:

• Utilized multichannel diffusion denuder sampling techniques with the Brigham Young University (BYU) organic sampling system (BOSS) and the high flow rate multi-system BYU organic sampling system (BIG BOSS).
• Collected samples during the Project MOHAVE summer intensive sampling program at the Meadview site, Grand Canyon National Park.
• Analyzed carbonaceous material using temperature programmed volatilization and characterized SVOCs using Gas Chromatography/Mass Spectrometry (GC/MS).

Main Results:

• BOSS collocated replicate samples showed agreement within ±14% for total fine particulate carbonaceous material.
• Approximately 50% of fine particulate organic material, primarily SVOCs, was lost from particles during sample collection.
• Identified and quantified n-alkanes, n-fatty acids, n-fatty methyl esters, and phthalic acid, determining their concentrations both retained and lost during sampling.

Conclusions:

• Standard sampling methods can lead to significant loss of semi-volatile organic compounds from fine particles.
• Understanding SVOC loss is critical for accurate assessment of atmospheric organic aerosols and their sources.
• Further research is needed to develop improved sampling strategies for SVOCs in fine particulate matter.