Real-time contributions of different types of VOCs to O3 formation in a typical industrial park: capturing features at hourly resolution

Abstract

Owing to a high nonlinear dynamic relationship between the precursors of NO_x-VOCs and O₃ formation in actual atmospheric conditions, traditional approaches—such as empirical kinetic models and air quality models—struggle to accurately quantify the hour-scale relative contributions of VOCs to O₃ production. Chemical industrial parks have become a critical challenge for ozone pollution control due to their high variability in emission intensities and types. This study aims to elucidate the real-time, hourly-scale relative contributions of alkanes, alkenes, aromatic hydrocarbons, and OVOCs to O₃ formation. By integrating Coupled Detrended Fluctuation Analysis (CDFA) with the Ozone Formation Potential (OFP) model, this research analyzes 12 months of VOC composition data collected in 2023 from a chemical industrial park. OFP analysis reveals that the contributions to O₃ formation followed an order of aromatics > OVOCs > alkanes > alkenes during non-O₃ pollution periods, which was consistent with the results from O₃ pollution days. A different trend was found from the results of CDFA analysis, with an order of aromatics > OVOCs > alkenes > alkanes. Importantly, evidence from the OFP not only verified the high effectiveness of the CDFA method, but also successfully revealed the spatial and temporal evolution characteristics of VOC contributions with different types. This study pioneers a novel application of CDFA, enabling precise quantification of the real-time contributions of various VOC species to O₃ formation. By significantly enhancing the resolution of VOCs relative contributions to O₃, this research offers an effective strategy for mitigating complex air pollution. The findings provide a robust framework for improving pollution control measures.