The Effect of Corona Virus Lockdown on Air Pollution: Evidence from the City of Brescia in Lombardia Region (Italy)

Abstract

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 (NO ) 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 NO 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.

The concentration of major air pollutants during the movement control order due to the COVID-19 pandemic in the Klang Valley, Malaysia

“…The results once again indicated that NO 2 and CO were the two major air pollutants which were clearly influenced by the reduction in motor vehicle emissions and other anthropogenic emissions during the MCO period. The same results were observed in other locations where the effect of lockdown was a reduction of NO 2 ( Baldasano, 2020 ; Cameletti, 2020 ; Kerimray et al, 2020 ; Lian et al, 2020 ; Pei et al, 2020 ) and CO ( Ghahremanloo et al, 2021 ; Kerimray et al, 2020 ). Other pollutants, such as PM and SO 2, are expected to originate from other sources such as soil dust, sea breezes, construction, coal-fired power plants and industrial activities, aside from the use of motor vehicles ( Azhari et al, 2018 ; Keywood et al, 2003 ; Mohtar et al, 2018 ; Sulong et al, 2017 ).…”

“…Lockdown reduced the number of vehicles on the roads, especially in major urban areas. Consequently, nitrogen dioxide (NO 2 ) gas, which mainly originates from the combustion of the fuel used for vehicles, has been dramatically reduced due to the reduction in vehicle exhaust emissions ( Baldasano, 2020 ; Cameletti, 2020 ; Dutheil et al, 2020 ; Kerimray et al, 2020 ; Krecl et al, 2020 ; Lal et al, 2020 ; Lian et al, 2020 ; Paital et al, 2020 ; Pei et al2020 ; Sarfraz et al, 2020 ; Tobías et al, 2020 ; Wang & Su, 2020 ). Wuhan, China is considered the epicentre of the coronavirus crisis and was the first city to impose lockdown measures, starting from 23rd January 2020 ( Chong et al, 2020 ; Leung et al, 2020 ; Wu et al, 2020 ).…”

Impact of COVID-19 Lockdowns on Air Quality and Health. Association between Concentrations of Tropospheric Ozone and Infection Cases and Deaths in Spain

“…Observing the concentration-time plots for the most populated city, Sevilla, most stations have a decreasing trend of NO 2 ( Figure 3a), being reduction rates from -55.4% (Torneo) to -72.0% (Alcala), with rapid tra cked roads. Similar results were found in the Lombardia Region where only in a heavy tra c zone NO 2 showed a signi cant decrease [ 23 ]. The rest of urban and suburban stations decreased over 60.4%.…”

COVID-19 and Air Pollution: Measuring Pandemic Impact to Air Quality in Five European Countries

“…Take the example of the 2008-2009 financial crisis, when carbon emissions soared by 6% in one year, after financial stimulus measures for rapid recovery of the economy went entirely to carbon-intensive industries [24]. The effects of air pollution changes have been investigated in several studies that observe the meaningful impact of nationwide lockdowns on atmospheric pollution [25][26][27][28]. Recent satellite data analysis-based reports by the Copernicus Atmosphere Monitoring Service confirm a reduction of air pollutants in the main European cities during the lockdown.…”