Long-range transport and airborne measurements of VOCs using proton-transfer-reaction mass spectrometry validated against GC-MS-canister data during the ASIA-AQ campaign

Abstract

Volatile organic compounds (VOCs) play a critical role in atmospheric chemistry, contributing to the formation of ozone, secondary PM_2.5 production, and global warming. This study investigates the spatial distribution and long-range transport dynamics of VOCs over South Korea, using airborne observations conducted during the 2024 Asian Air Quality campaign. VOC concentrations were measured in urban, industrial, and long-range transport scenarios using proton transfer reaction-time-of-flight mass spectrometry (MS) and gas chromatography–MS with canister sampling. The results demonstrate that benzene shows significant vertical and spatial dispersion during long-range transport due to its intermediate atmospheric lifetime, which allows it to persist and impact downwind air quality. Additionally, Chlorinated VOCs, such as 1,2-dichloroethane and 1,2,4-trichlorobenzene, display transport behaviors. Their relatively consistent concentrations during long-range transport emphasize the influence of industrial activities, including coal combustion and petrochemical processes, as major sources. Elevated levels of chlorinated VOCs were primarily associated with emissions from industrial regions in Chungnam, while aromatic VOCs were predominantly linked to urban traffic emissions. These findings underscore the need for international cooperation to combat transboundary pollution and highlight the importance of comprehensive air quality management strategies that address both urban and industrial emission sources. This study provides essential insights into the atmospheric behavior of VOCs and emphasizes the need for targeted policies to effectively regulate air pollution.