Vertical Redistribution of Ozone Precursor Proxies During Typhoon Peripheral Periods: Insights From MAX‐DOAS and GEOS‐Chem

Abstract Typhoon peripheral conditions modulate the formation and atmospheric fate of ozone precursors, yet the vertical distribution and the underlying physical‐chemical drivers remain less constrained. Here, we examine the vertical profiles of ozone precursor proxies, including formaldehyde (HCHO), glyoxal (CHOCHO), and nitrogen dioxide (NO 2 ), in the Pearl River Delta (PRD) in China during the 2023–2024 typhoon seasons using ground‐based Multi‐Axis Differential Optical Absorption Spectroscopy. Under peripheral conditions, tropospheric columns of HCHO and CHOCHO increase by 30.8% and 34.4%, respectively, with the most pronounced enhancements occurring within 0.5–1.0 km. GEOS‐Chem budget analysis indicates that such shift upward of vertical peaks is driven by intensified enhanced vertical transport that enhances net production by 14.0%–25.0% at 0.5–1.0 km. In contrast, NO 2 profiles remain stable, due to a rebalance between strengthened upward convection and accelerated chemical loss. Such vertical redistributions shift the ozone sensitivity regime from volatile organic compound‐limited to NO x ‐limited within 0.5–1.0 km. Our findings underscore the necessity of height‐resolved monitoring for refining ozone mitigation strategies in coastal cities.