This study investigated impacts of regional transport and meteorology on ground-level ozone (O₃) in the smog season (April–September) during 1996–2015 in Windsor, Ontario, Canada. Data from five upwind stations in the US, which are within 310 km (i.e., Allen Park and Lansing in Michigan, Erie, National Trail School, and Delaware in Ohio), were included to assess the regional characteristics of O₃. The five US stations showed high degrees of similarity with O₃ concentrations in Windsor, with overall strong correlations (r = 0.567–0.876 for hourly O₃ and r = 0.587–0.92 for 8 h max O₃ concentrations) and a low degree of divergence, indicating that O₃ pollution in the study area shares regional characteristics. Meteorological conditions played important roles in O₃ levels in Windsor. High O₃ concentrations were associated with southerly and southwesterly air mass from which polluted and hot air mass was transported and that enhanced local photochemical O₃ production. In contrast, northerly flows brought in clean, cool, and dry air mass, and led to low O₃ concentrations. Strong correlations were found between numbers of days with 8 h max O₃ concentrations greater than 70 ppb and numbers of days with daily max temperature greater than 30 °C, as well as between daily max temperatures and 8 h max O₃ concentrations. Nearly half (45%) of the high O₃ days (≥90th percentile) occurred in dry tropical weather during 1996–2015, and the 90th percentile 8 h max O₃ was associated with dry tropical weather. Occurrences of both southerly flow hours and dry tropical weather type in the smog season increased during the study period. If there were more hot and dry days in the next few decades due to climate change, the effect of emission control on reducing peak O₃ values would be diminished. Therefore, continued regional and international efforts are essential to control precursors’ emissions and to mitigate O₃ pollution in Windsor.

中文翻译：

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加拿大温莎地区运输和气象学对地面臭氧的影响

这项研究调查了1996-2015年加拿大安大略省温莎市的烟雾季节（4月至9月），区域运输和气象对地面臭氧（O ₃）的影响。包括来自美国三个上风站的数据，这些数据位于310公里以内（即密歇根州的艾伦公园和兰辛，伊利大学，国家步道学校和俄亥俄州的特拉华州），以评估O ₃的区域特征。美国的五个站点与温莎中的O ₃浓度具有高度相似性，总体上具有很强的相关性（每小时O _3的r = 0.567–0.876，最大O ₃浓度的r = 0.587–0.92 ）和低程度的差异，表示O ₃研究区的污染具有区域特征。气象条件在温莎的O ₃水平中起着重要作用。O _3的高浓度与向南和向西南的空气团有关，从那里输送了污染的空气和热空气团，并提高了当地光化学O _3的产生。相反，向北的气流带来了清洁，凉爽和干燥的空气质量，导致O ₃浓度降低。发现最大8 h O ₃浓度大于70 ppb的天数与每天最高温度大于30°C的天数之间，以及每天最高温度与8 h最高O _{3之间的强相关性}浓度。在1996-2015年间，高O ₃天（≥90 ％）中近一半（45％）发生在干燥的热带天气中，而最高90 h的8 h max O ₃与热带干燥天气有关。在研究期间，在烟雾季节，向南的流动时间和干燥的热带天气类型的发生率都增加了。如果未来几十年由于气候变化而有更多的炎热和干燥的日子，则排放控制对降低O ₃峰值的影响将减弱。因此，持续的区域和国际努力对于控制温莎的前驱物排放和减轻O ₃污染至关重要。