Super typhoon triggers severe ozone pollution in Pearl River Delta via stratospheric intrusion

Abstract Surface ozone (O₃) pollution poses well-documented threats to global ecosystems and public health. While stratospheric intrusion is regarded as an important source of surface O₃, its contribution to O₃ concentrations is typically small compared to local near-surface photochemical processes. However, a severe O₃ pollution event occurred in China’s Pearl River Delta region with O₃ concentrations increasing by 28.2 μ g m −3 during September 2–4, 2024. Our Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model analysis indicates that the maximum contribution of stratospheric origin air masses can reach 71.0% due to a distant-source transport of stratospheric intrusion caused by super typhoon YAGI. Distinct from conventional localized stratospheric intrusion, this distant-source transport, driven by a typhoon and mid-latitude systems, enables vertical transport and horizontal delivery exceeding 2000 km, with typhoon-induced subsidence completing the grounding of stratospheric O₃. These findings reveal a new dynamic mechanism of vertical downward transport for stratospheric mass and underscore the necessity of joint prevention measures against stratospheric intrusion. Failure to elucidate the mechanisms against the backdrop of a projected increase in super typhoon events may lead to a severe underestimation of stratospheric intrusion contributions to tropospheric ozone pollution.