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

Author(s):Show less -

Rudke, A. P. ^{[1, 2]} ; Martins, J. A. ^{[2, 3]} ; de Almeida, D. S. ^{[2, 4]} ; Martins, L. D. ^[2] ; Beal, A. ^[2] ; Hallak, R. ^[5] ; Freitas, E. D. ^[5] ; Andrade, M. F. ^[5] ; Foroutan, H. ^[6] ; Baek, B. H. ^[7] ; Albuquerque, T. T. de A. ^{[1, 8]}

Affiliation

^[1] Univ Fed Minas Gerais, Dept Sanit & Environm Engn, Av Pres Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG - Brazil

^[2] Univ Tecnol Fed Parana, Av Pioneiros 3131, BR-86036370 Londrina, Parana - Brazil

^[3] Lund Univ, Div Water Resources Engn, John Ericssons Vag 1, Lund - Sweden

^[4] Univ Fed Sao Carlos, Rod Washington Luiz, Km 235, SP310, BR-13565905 Sao Carlos - Brazil

^[5] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao, 1226, Cidade Univ, BR-05508090 Sao Paulo - Brazil

^[6] Virginia Polytech Inst & State Univ, Dept Civil & Environm Engn, Blacksburg, VA 24061 - USA

^[7] George Mason Univ, Coll Sci, 4400 Univ Dr, Fairfax, VA 22030 - USA

^[8] Univ Fed Espirito Santo, Post Grad Program Environm Engn, Av Fernando Ferrari 514, BR-29075910 Vitoria, ES - Brazil

• Document type: Journal article
• Source: Environmental Research; v. 198, JUL 2021.
• Web of Science Citations: 0

Abstract

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, Sao Paulo, severely impacted by COVID-19. Ground-based air quality data (PM10, PM2.5, CO, SO2, NOx, NO2, 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 Sao Paulo State. However, special attention should be given to the Metropolitan Area of Sao 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 NOx, 40% in NO, 19% in SO2, 15% in PM2.5, and 8% in PM10 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 NOx, 63% in NO, 12% in SO2, 23% in PM2.5, 18% in PM10, and 16% in O-3 concentrations when compared to the same period in 2019. On the other hand, Cubatao, 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. (AU)

• FAPESP's process: 16/18438-0 - São Paulo Metropolitan Area, jointly tracking climate change and air quality - METROCLIMA-MASP
• Grantee: Maria de Fátima Andrade
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants