A Novel Automated Sampler Designed for Improved Spatiotemporal Resolution of Volatile Organic Compound Measurements

JACKSON RYAN, Paulus Bauer, Ana Luisa Santiago O. Vilela, Alejandra Hernández-Terán, María Rebolleda-Gómez, Celia Faiola, University of California, Irvine

     Abstract Number: 332
     Working Group: Instrumentation and Methods

Abstract
Secondary Organic Aerosols (SOA) can form through atmospheric oxidation of volatile organic compounds (VOCs) that are emitted from biogenic and anthropogenic sources. Monoterpenes (MTs) and sesquiterpenes (SQTs) are especially important because they are major emissions from terrestrial vegetation. Quantification of structural isomers is critical because different terpene isomers can vary in atmospheric reactivity by orders of magnitude and can have significantly different SOA mass yields. Therefore, even with low mixing ratios, it is possible for some MTs and SQTs to play a more important role in atmospheric chemistry processes. However, isomer-specific measurements often require extensive labor and/or specialized field instrumentation leading to challenges in adequate spatiotemporal resolution of these measurements – particularly in remote areas. This study involved building and testing a new automated cartridge sampler system that can be deployed in urban and remote environments to address this critical challenge. The sampler was designed using PFA tubing and custom PEEK manifolds to limit sampling line losses upstream of the sorbent cartridges. Additionally, the sampler is automated and can be operated using solar-charged battery-power to allow for collection of up to 12 individual samples between sample retrievals. Furthermore, the sampler was designed with 2 separate inlets connected to 6 cartridges each facilitating the ability to connect the sampling lines to two different locations or to collect 2 cartridges simultaneously for duplicate measurements.

Sampler design and proof-of-concept measurements will be presented. Preliminary testing on the sampler has been conducted, leveraging an ongoing plant-microbe interactions study at UC Irvine. Soil VOCs were measured from different treatment groups. Soil VOC composition and concentrations from the different treatment groups will be presented.