Unrecognized Emissions and Health Risks of Intermediate-Volatility Organic Compounds in Vehicle Cabins: Insights from a Nontargeted Analytical Approach

With increasing vehicle ownership and commuting time, vehicle in-cabin air quality has emerged as a growing public health concern. However, the lack of comprehensive characterization of organic compounds across the full volatility range has limited our understanding of their chemical complexity and health impacts, particularly for intermediate-volatility organic compounds (IVOCs). Here, we employed comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS) for non-targeted analysis of pollutants in in-use passenger cars, featuring three types of interior upholstery, i.e., real leather, leatherette, and textile. A total of 176 gaseous organic species were identified. Vehicles with real leather (592.7 ± 229.1 μg m^–3) and leatherette interiors (629.5 ± 137.9 μg m^–3) exhibited total organic concentrations roughly 2.5-fold higher than those with textile upholstery (246.1 ± 22.9 μg m^–3). Alkanes accounted for 32–58% for all tested vehicles, followed by oxygenated components (25–34%). Notably, IVOCs not only accounted for 52–60% of in-cabin pollutants, but also posed considerable health concerns, contributing 55–62% to respiratory toxicity and 45–56% to carcinogenicity. These findings underscore the overlooked role of IVOCs in vehicular microenvironment and provide crucial insights for future in-cabin air quality regulations and health risk mitigation strategies.