Separating the impact of gradual lockdown measures on air pollutants from seasonal variability

Hörmann, Siegfried; Jammoul, Fatima; Kuenzer, Thomas; Stadlober, Ernst

doi:10.1016/j.apr.2020.10.011

Cited by 18 publications

(17 citation statements)

References 10 publications

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“…However, researchers have provided different explanations according to their understanding and based on the local meteorological and emission conditions. Donzelli et al [20], Marinello et al, [24] and Hormann et al [22] thought that people used the indoor heating system more frequently as they spent more time indoors during the lockdown, which increased PM emissions. They suggested further research to fully comprehend this matter.…”

Section: Relationship Between Air Pollutant Concentrations and Mobilitymentioning

confidence: 99%

“…They suggested further research to fully comprehend this matter. Hormann et al [22] stated that the reduction in traffic levels did not result in a significant reduction in PM 10 levels because PM 10 pollution in urban areas is not a monocausal phenomenon. They mentioned that increases in indoor residential emissions could be a possible cause for the positive PM 10 gain during the lockdown period.…”

Section: Relationship Between Air Pollutant Concentrations and Mobilitymentioning

confidence: 99%

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Changes in Air Quality Associated with Mobility Trends and Meteorological Conditions during COVID-19 Lockdown in Northern England, UK

et al. 2021

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The COVID-19 pandemic triggered catastrophic impacts on human life, but at the same time demonstrated positive impacts on air quality. In this study, the impact of COVID-19 lockdown interventions on five major air pollutants during the pre-lockdown, lockdown, and post-lockdown periods is analysed in three urban areas in Northern England: Leeds, Sheffield, and Manchester. A Generalised Additive Model (GAM) was implemented to eliminate the effects of meteorological factors from air quality to understand the variations in air pollutant levels exclusively caused by reductions in emissions. Comparison of lockdown with pre-lockdown period exhibited noticeable reductions in concentrations of NO (56.68–74.16%), NO2 (18.06–47.15%), and NOx (35.81–56.52%) for measured data. However, PM10 and PM2.5 levels demonstrated positive gain during lockdown ranging from 21.96–62.00% and 36.24–80.31%, respectively. Comparison of lockdown period with the equivalent period in 2019 also showed reductions in air pollutant concentrations, ranging 43.31–69.75% for NO, 41.52–62.99% for NOx, 37.13–55.54% for NO2, 2.36–19.02% for PM10, and 29.93–40.26% for PM2.5. Back trajectory analysis was performed to show the air mass origin during the pre-lockdown and lockdown periods. Further, the analysis showed a positive association of mobility data with gaseous pollutants and a negative correlation with particulate matter.

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Section: Relationship Between Air Pollutant Concentrations and Mobilitymentioning

confidence: 99%

Section: Relationship Between Air Pollutant Concentrations and Mobilitymentioning

confidence: 99%

Changes in Air Quality Associated with Mobility Trends and Meteorological Conditions during COVID-19 Lockdown in Northern England, UK

et al. 2021

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“…The time-scale variability in pollutant concentrations is linked to the emission sources and the weather conditions that affect the dispersion and the long-range transport from other regions ( Andersson et al, 2007 ; He et al, 2017 ; Martins et al, 2018 ). Studies carried out during the pandemic in other regions demonstrate the impact of meteorological variables on air quality, showing that it is impossible to assess changes in pollutant concentrations in a dissociated manner ( Hörmann et al, 2020 ; Ordóñez et al, 2020 ; Petetin et al, 2020 ). Furthermore, in Brazil, an important factor that cannot be neglected are the fires outbreaks, which affect different regions of the country, changing the level of pollutant concentrations, even in large centers ( Lopes et al, 2012 ; Martins et al, 2018 ; Pereira et al, 2011 ; Targino et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

How mobility restrictions policy and atmospheric conditions impacted air quality in the State of São Paulo during the COVID-19 outbreak

Rudke

Martins

Almeida

et al. 2021

Environmental Research

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Mobility restrictions are among actions to prevent the spread of the COVID-19 pandemic and have been pointed as reasons for improving air quality, especially in large cities. However, it is crucial to assess the impact of atmospheric conditions on air quality and air pollutant dispersion in the face of the potential variability of all sources. In this study, the impact of mobility restrictions on the air quality was analyzed for the most populous Brazilian State, São Paulo, severely impacted by COVID-19. Ground-based air quality data (PM 10 , PM 2.5 , CO, SO 2 , NO x , NO 2 , NO, and O 3 ) were used from 50 automatic air quality monitoring stations to evaluate the changes in concentrations before (January 01 - March 25) and during the partial quarantine (March 16 - June 30). Rainfall, fires, and daily cell phone mobility data were also used as supplementary information to the analyses. The Mann-Whitney U test was used to assess the heterogeneity of the air quality data during and before mobility restrictions. In general, the results demonstrated no substantial improvements in air quality for most of the pollutants when comparing before and during restrictions periods. Besides, when the analyzed period of 2020 is compared with the year 2019, there is no significant air quality improvement in the São Paulo State. However, special attention should be given to the Metropolitan Area of São Paulo (MASP), due to the vast population residing in this area and exposed to air pollution. The region reached an average decrease of 29% in CO, 28% in NO x , 40% in NO, 19% in SO 2 , 15% in PM 2.5 , and 8% in PM 10 concentrations during the mobility restrictions period compared to the same period in 2019. The only pollutant that showed an increase in concentration was ozone, with a 20% increase compared to 2019 during the mobility restrictions period. Before the mobility restrictions period, the region reached an average decrease of 30% in CO, 39% in NO x , 63% in NO, 12% in SO 2 , 23% in PM 2.5 , 18% in PM 10 , and 16% in O 3 concentrations when compared to the same period in 2019. On the other hand, Cubatão, a highly industrialized area, showed statistically significant increases above 20% for most monitored pollutants in both periods of 2020 compared to 2019. This study reinforces that the main driving force of pollutant concentration variability is the dynamics of the atmosphere at its various time scales. An abnormal rainy season, with above average rainfall before the restrictions and below average after it, generated a scenario in which the probable significant reductions in emissions did not substantially affect the concentration of pollutants.

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“…Numerous studies around the world, as in China and East Asia [13][14][15], India [16][17][18], Southeast Asia [19,20], Europe [21][22][23][24][25][26], North America [27,28] and South America [29,30], have analyzed the effect of COVID-19 lockdowns in spring 2020 on concentrations of particulate matter (PM) and gaseous pollutants (NO x , CO, O 3 , SO 2 , NH 3 , etc.). All these studies agree on an unprecedented reduction of air pollution worldwide due to drastic limitations in traffic and industrial activity [31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Assessment of the COVID-19 Lockdown Effects on Spectral Aerosol Scattering and Absorption Properties in Athens, Greece

et al. 2021

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COVID-19 is evolving into one of the worst pandemics in recent history, claiming a death toll of over 1.5 million as of December 2020. In an attempt to limit the expansion of the pandemic in its initial phase, nearly all countries imposed restriction measures, which resulted in an unprecedented reduction of air pollution. This study aims to assess the impact of the lockdown effects due to COVID-19 on in situ measured aerosol properties, namely spectral-scattering (bsca) and absorption (babs) coefficients, black carbon (BC) concentrations, single-scattering albedo (SSA), scattering and absorption Ångström exponents (SAE, AAE) in Athens, Greece. Moreover, a comparison is performed with the regional background site of Finokalia, Crete, for a better assessment of the urban impact on observed differences. The study examines pre-lockdown (1–22 March 2020), lockdown (23 March–3 May 2020) and post-lockdown (4–31 May 2020) periods, while the aerosol properties are also compared with a 3–4 year preceding period (2016/2017–2019). Comparison of meteorological parameters in Athens, between the lockdown period and respective days in previous years, showed only marginal variation, which is not deemed sufficient in order to justify the notable changes in aerosol concentrations and optical properties. The largest reduction during the lockdown period was observed for babs compared to the pre-lockdown (−39%) and to the same period in previous years (−36%). This was intensified during the morning traffic hours (−60%), reflecting the large decrease in vehicular emissions. Furthermore, AAE increased during the lockdown period due to reduced emissions from fossil-fuel combustion, while a smaller (−21%) decrease was observed for bsca along with slight increases (6%) in SAE and SSA values, indicating that scattering aerosol properties were less affected by the decrease in vehicular emissions, as they are more dependent on regional sources and atmospheric processing. Nighttime BC emissions related to residential wood-burning were slightly increased during the lockdown period, with respect to previous-year means. On the contrary, aerosol and pollution changes during the lockdown period at Finokalia were low and highly sensitive to natural sources and processes.

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Separating the impact of gradual lockdown measures on air pollutants from seasonal variability

Cited by 18 publications

References 10 publications

Changes in Air Quality Associated with Mobility Trends and Meteorological Conditions during COVID-19 Lockdown in Northern England, UK

Changes in Air Quality Associated with Mobility Trends and Meteorological Conditions during COVID-19 Lockdown in Northern England, UK

How mobility restrictions policy and atmospheric conditions impacted air quality in the State of São Paulo during the COVID-19 outbreak

Assessment of the COVID-19 Lockdown Effects on Spectral Aerosol Scattering and Absorption Properties in Athens, Greece

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