Advancing Ambient Air Analysis: A Portable Gas Chromatograph for Biogenic VOC Monitoring in the ACTRIS Network

Biogenic volatile organic compounds (BVOCs) play a pivotal role in atmospheric chemistry, significantly contributing to ozone formation and secondary organic aerosol (SOA) precursors. Their accurate and sensitive detection in ambient air is therefore of significant importance for networks such as ACTRIS, which focus on atmospheric research and climate monitoring. However, current analytical methods often lack the sensitivity, selectivity, and portability required for reliable field measurements.Within the PurPest EU project, novel gas chromatographic systems, both portable and rack mounted, were developed, integrating a miniaturized pre-concentration module and an optimized photoionization detector (PID). These systems were specifically designed to address the challenges of detecting trace-level VOCs in complex environmental matrices. The PID offers high sensitivity and robustness for volatile organic compound (VOC) measurements and presents a significant operational advantage, due to its capability for both VOCs and BVOCs detection. However, it lacks chemical selectivity because it responds to a broad spectrum of VOCs rather than to specific target molecules. To overcome this limitation, a chromatographic column was included to separate individual components of the gas mixture, allowing for a more accurate characterization of VOC profiles.These analytical systems were jointly tested with three partner universities to assess the sensor unit’s capacity to detect VOCs emitted by pest-stressed plants. In each trial, these systems functioned autonomously 24 hours per day for two consecutive weeks without human supervision, while analyzing various sample environments: laboratory air, air surrounding healthy plants, and air surrounding pest-infested plants.For the ACTRIS network, these gas chromatograph offer a promising tool for enhancing the analysis of biogenic VOCs in ambient air. Their sensitivity, selectivity, and field-readiness make it well-suited for addressing the network’s research priorities, including the study of ozone and SOA precursors.