Despite the societal and economic impacts of the COVID-19 pandemic, the lockdown measures put in place by the Italian government provided an unprecedented opportunity to increase our knowledge of the effect transportation and industry-related emissions have on the air quality in our cities. This study assessed the effect of reduced emissions during the lockdown period, due to COVID-19, on air quality in three Italian cities, Florence, Pisa, and Lucca. For this study, we compared the concentration of particulate matter PM₁₀, PM_2.5, NO₂, and O₃ measured during the lockdown period, with values obtained in the same period of 2019. Our results show no evidence of a direct relationship between the lockdown measures implemented and PM reduction in urban centers, except in areas with heavy traffic. Consistent with recently published studies, we did, however, observe a significant decrease in NO₂ concentrations among all the air-monitoring stations for each city in this study. Finally, O₃ levels remained unchanged during the lockdown period. Of note, there were slight variations in the meteorological conditions for the same periods of different years. Our results suggest a need for further studies on the impact of vehicular traffic and industrial activities on PM air pollution, including adopting holistic source-control measures for improved air quality in urban environments.

中文翻译：

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Covid-19封锁对意大利三个中型城市空气质量的影响

尽管COVID-19大流行对社会和经济产生了影响，但意大利政府采取的封锁措施仍为我们提供了前所未有的机会，使我们更加了解交通和与行业相关的排放对城市空气质量的影响。这项研究评估了由于COVID-19而在锁定期内减少排放对意大利三个城市佛罗伦萨，比萨和卢卡的空气质量的影响。在本研究中，我们比较了颗粒物PM ₁₀，PM _2.5，NO ₂和O ₃的浓度在锁定期间进行了测量，并获得了2019年同期的值。我们的结果表明，除了交通繁忙的地区以外，没有证据表明实施的锁定措施与城市中心的PM降低之间存在直接关系。然而，与最近发表的研究一致，我们确实观察到了该研究中每个城市的所有空气监测站中NO ₂浓度的显着降低。最后，O ₃锁定期间水平保持不变。值得注意的是，不同年份同一时期的气象条件略有不同。我们的结果表明，有必要进一步研究车辆交通和工业活动对PM空气污染的影响，包括采取整体污染源控制措施，以改善城市环境中的空气质量。