颱風被認為是對香港空氣質量有重大影響的最主要的氣象事件。在這項研究中，使用表面連續測量數據和臭氧探空儀剖面資料，對10年中的33個發作日（ED）進行了綜合分析。在這項研究中，將以香港為中心超過800公里半徑的颱風過濾掉，然後記錄了每個急診室的颱風位置。時間序列分析顯示10年內的ED通常發生在夏末和秋季。較高的O3事件是造成有利的東北風，中等風速，下沉，強烈的太陽輻射，大氣倒置和地表溫度高的原因，這些因素通常在颱風發生前發生。人們發現這些因素與颱風的位置密切相關：大多數ED發生在颱風位於香港東南部和東部時。向後的軌跡表明，典型ED的空氣質量主要來自中國大陸。此外，西南颱風的特殊情況分析說明了夜間化學過程中Ozone形成的限制因素，並暗示了在強沉降條件下 侵入UTLS地區的可能性。

Typhoons are considered as the most predominant meteorological event that have major influences on air quality in Hong Kong. In this study, using surface continous measurement data together with ozonesonde profiles, 33 episode days (EDs) in 10 years were comprehensive analyzed. In this study, typhoons that centered further than 800km radius around Hong Kong were filtered out then location of typhoons of each ED was noted. Time-series analysis shows that EDs in 10 years often occur in late summer and autumn. Favourable northeasterly winds, moderate wind speed, subsidence, intense solar radiation, atmospheric inversion and high surface temperature which often occur in pre-typhoon days were responsible for those high O3 events. Those factors are found to be strongly associated with the location of typhoons: most of EDs occured when typhoons located in southeastern and eastern of Hong Kong. Backward trajectory shows that air mass origin in typical EDs are mainly from mainland China. Besides, exceptional cases analysis of an southwestern typhoon illustrates the limiting factors from night-time chemistry of O3 formation and suggests the possibility of O3 instrusion from UTLS regions under strong subsidence condition.

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