The Effect of Corona Virus Lockdown on Air Pollution: Evidence from the City of Brescia in Lombardia Region (Italy)
The Effect of Corona Virus Lockdown on Air Pollution: Evidence from the City of Brescia in Lombardia Region (Italy)
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DOI：
10.1016/j.atmosenv.2020.117794
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发表时间：
2020-10-15
影响因子：
5
通讯作者：
Cameletti, Michela
中科院分区：
文献类型：
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作者：
Cameletti, Michela
在意大利爆发冠状病毒大流行后，政府已采取非常措施，包括全国封锁，以防止感染蔓延。这种特殊的情况导致整个波河流域的空气污染水平下降，波河流域通常被称为欧洲颗粒物（PM）和二氧化氮（NO2）浓度污染最严重的地区之一。本报告的主要目的是评估封锁对改善空气质量的成效。特别是，采用中断时间序列建模方法来测试污染物时间序列的水平和趋势在封锁措施后是否发生了重大变化。该案例研究涉及布雷西亚市（北方意大利），重点是封锁前（2020年1月1日至3月7日）和封锁后（2020年3月8日至3月27日）的比较。通过调整气象和周日效应，结果表明，在干预后的空气质量发生了显着变化，观察到只有一个单一的NO2站位于交通繁忙的地区。特别是，时间序列斜率的估计值，即与时间单位增加相关的浓度的预期变化，在锁定后从-0.25降至-1.67。对于其余的站，没有显着的变化，发现在浓度时间序列比较两个时期。这证实了所考虑区域的空气污染物浓度动态的复杂性，这不仅与排放源有关，而且还取决于其他因素，例如（微观和宏观）气象条件以及大气中的化学和物理过程，这些因素都与封锁措施无关。
After the outbreak of Corona virus pandemic in Italy, the government has taken extraordinary measures, including a national lockdown, to prevent the spread of the infection. This extraordinary situation has led to a reduction in air pollution levels measured in the whole Po Valley, usually known as one of the most polluted areas in Europe in terms of particulate matter (PM) and nitrogen dioxide (NO2) concentrations. The main aim of this paper is to evaluate the effectiveness of the lockdown on the air quality improvement. In particular, an interrupted time series modelling approach is employed to test if a significant change in the level and the trend of the pollutant time series has occurred after the lockdown measure. The case study regards the city of Brescia (Northern Italy) and focuses on the comparison of the period before (January 1st-March 7th, 2020) and after (March 8th-March 27th, 2020) the lockdown. By adjusting for meteorology and Sunday effect, the results show that a significant change in air quality occurring in the post intervention period was observed only for a single NO2 station located in a heavy traffic zone. In particular, the estimate of the time series slope, i.e. the expected change in the concentration associated with a time unit increase, decreases from-0.25 to-1.67 after the lockdown. For the remaining stations, no significant change was found in the concentration time series when comparing the two periods. This confirms the complexity of air pollutant concentration dynamics for the considered area, which is not merely related to emission sources but depends also on other factors as, for example, (micro and macro) meteorological conditions and the chemical and physical processes in the atmosphere, which are all independent of the lockdown measure.