Collivignarelli Maria Cristina, De Rose Claudio, Abbà Alessandro, Baldi Marco, Bertanza Giorgio, Pedrazzani Roberta, Sorlini Sabrina, Carnevale Miino Marco
Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 3, 27100, Pavia, Italy.
Interdepartmental Centre for Water Research, University of Pavia, via Ferrata 3, 27100, Pavia, Italy.
Process Saf Environ Prot. 2021 Feb;146:952-960. doi: 10.1016/j.psep.2020.12.029. Epub 2020 Dec 25.
Nitrogen dioxide (NO) can have harmful effects on human health and can act as a precursor for the formation of other air pollutants in urban environment such as secondary PM and ozone. The lockdown measures for CoViD-19 allowed to simulate on a large scale the massive and prolonged reduction of road traffic (the main source for NO in urban environment). This work aims to selectively assess the maximum impact that total traffic blocking measures can have on NO. For this reason, three megacities (London, Milan and Paris) were chosen which had similar characteristics in terms of climatic conditions, population, policies of urban traffic management and lockdown measures. 52 air quality control units have been used to compare data measured in lockdown and in the same periods of previous years, highlighting a significant decrease in NO concentration due to traffic (London: 71.1 % - 80.8 %; Milan: 8.6 % - 42.4 %; Paris: 65.7 % - 79.8 %). In 2020 the contribution of traffic in London, Milan and Paris dropped to 3.3 ± 1.3 μg m, 6.1 ± 0.8 μg m, and 13.4 ± 1.5 μg m, respectively. Despite the significant reduction in the NO concentration, in UT stations average NO concentrations higher than 40 μg m were registered for several days. In order to reduce the pollution, the limitation of road traffic could be not enough, but a vision also aimed at rethink the vehicles and their polluting effects should be developed.
二氧化氮（NO）会对人体健康产生有害影响，并且在城市环境中可作为其他空气污染物形成的前体，如二次颗粒物（PM）和臭氧。新冠疫情防控的封锁措施使得能够大规模模拟道路交通（城市环境中NO的主要来源）的大幅且长期减少。这项工作旨在有针对性地评估全面交通封锁措施对NO可能产生的最大影响。因此，选择了三个特大城市（伦敦、米兰和巴黎），它们在气候条件、人口、城市交通管理政策和封锁措施方面具有相似特征。利用52个空气质量控制单元对封锁期间及前几年同期测量的数据进行比较，结果表明由于交通量减少，NO浓度显著下降（伦敦：71.1% - 80.8%；米兰：8.6% - 42.4%；巴黎：65.7% - 79.8%）。2020年，伦敦、米兰和巴黎交通排放的贡献分别降至3.3±1.3μg/m、6.1±0.8μg/m和13.4±1.5μg/m。尽管NO浓度大幅降低，但在城市交通监测站，仍有几天记录到平均NO浓度高于40μg/m。为了减少污染，仅限制道路交通可能还不够，还应制定旨在重新审视车辆及其污染影响的愿景。
