COVID-19 pandemic: Impacts on the air quality during the partial lockdown in São Paulo state, Brazil

Abstract

In early March 2020, the World Health Organization declared the COVID-19 as a pandemic, and in late March 2020 partial lockdown was ordered by the São Paulo state government. The aim of this study was to assess impacts on air quality in São Paulo - Brazil, during the partial lockdown implemented to provide social distancing required due to the COVID-19 pandemic. We have analyzed data from four air quality stations in São Paulo, Brazil to assess air pollutant concentration variations during the partial lockdown. Data were compared to the five-year monthly mean and to the four-week before the partial lockdown. Overall, drastic reductions on NO (up to -77.3%), NO₂ (up to -54.3%), and CO (up to -64.8%) concentrations were observed in the urban area during partial lockdown compared to the five-year monthly mean. By contrast, an increase of approximately 30% in ozone concentrations was observed in urban areas highly influenced by vehicle traffic, probably related to nitrogen monoxide decreases. Although the partial lockdown has contributed to a positive impact on air quality, it is important to take into account the negative impacts on social aspects, considering the deaths caused by COVID-19 and also the dramatic economic effects.

Keywords: Atmospheric pollution; Carbon monoxide; Latin America; NO(2); Nitrogen monoxide; SARS-CoV-2.

Graphical abstract

Fig. 1

Daily mean concentrations of air pollutants: PM_2.5 (μg∙m^—3), PM₁₀ (μg∙m^—3), O₃ (μg∙m^—3), SO₂ (μg∙m^—3), NO (μg∙m^—3), NO₂ (μg∙m^—3), NOx (ppb), and CO (ppm) both in the four-week before and in the four-week during the partial lockdown in São Paulo, Brazil. Bars in the ozone graph indicate days with adverse conditions to ozone dispersion.

Fig. 2

Mean levels of tropospheric NO₂ measured by the S5p/TROPOMI-ESA both in the four-week before and in the four-week during the partial lockdown in São Paulo, Brazil, compared to the same period in 2019.