Impacts of Covid-19 interventions on air quality: evidence from Brazilian metropolitan regions

Abstract

The Covid-19 pandemic has negatively disrupted the way our economy and society functions. Nonetheless, there have also been some positive externalities of the pandemic on the environment. This paper aims to evaluate the concentration of nitrogen dioxide in Brazilian metropolitan regions after the policies adopted to confront Covid-19. In terms of methodological approach, the study employs cross-sectional quantitative analyses to compare the period of 36 days, i.e., 12 March to 16 April-before (in 2019) and after (in 2020) the pandemic declaration. The data were obtained from the Sentinel 5-P low-Earth polar satellite concerning Brazilian metropolitan regions (n = 24). Thorough spatial and statistical analyses were undertaken to identify the pre- and during pandemic nitrogen dioxide concentrations. Complementarily, Spearman's correlation test was performed with variables that impact air quality. The study results a fall in nitrogen dioxide concentration levels in 21 of the 24 metropolitan regions which was observed. The Spearman's correlation coefficient between the nitrogen dioxide variation and the vehicle density was 0.485, at a significance level of 0.05. With these findings in mind, the paper advocates that while the pandemic has a significant negative consequence on the health of population globally, a series of measures that result in a new social organization directly interfere in the reduction of air pollution that contributes to the quality of the air we breathe.

Keywords: Air quality; Brazil; Climate change; Covid-19; Nitrogen dioxide; Urban policy.

Fig. 1

Thematic maps of the mean concentration of NO2 from March 12 to April 16, 2019 and 2020, in Baixada Santista metropolitan region

Fig. 2

Thematic maps of the mean concentration of NO₂ from March 12 to April 16, 2019 and 2020, in the metropolitan regions of Belém, Belo Horizonte, Campinas, and Curitiba

Fig. 3

Thematic maps of the mean concentration of NO₂ from March 12 to April 16, 2019 and 2020, in the metropolitan region of Florianópolis, Fortaleza, Goiânia, and Maceió

Fig. 4

Thematic maps of the mean concentration of NO₂ from March 12 to April 16, 2019 and 2020, in the metropolitan regions of Manaus, Natal, Porto Alegre, Recife

Fig. 5

Thematic maps of the mean concentration of NO₂ from March 12 to April 16, 2019 and 2020, in the metropolitan regions of Rio de Janeiro, Salvador, São Luís, and São Paulo

Fig. 6

Thematic maps of the mean concentration of NO₂ from March 12 to April 16, 2019 and 2020, in the metropolitan regions of Sorocaba, Teresina, São José dos Campos (Vale do Paraíba), and Vitória

Fig. 7

Thematic maps of the mean concentration of NO₂ from March 12 to April 16, 2019 and 2020, in the metropolitan regions of Brasília (Federal District), Cuiabá, and Petrolina

Fig. 8

Thematic maps of reduction in NO₂ concentrations from March 12 to April 16, 2019 and 2020, in the metropolitan regions of Baixada Santista, Belém, Belo Horizonte, Campinas, Curitiba, Florianópolis, Fortaleza, Goiânia,

Fig. 9

Thematic maps of reduction in NO₂ concentrations from March 12 to April 16, 2019 and 2020, in the metropolitan regions of Maceió, Manaus, Natal, Porto Alegre, Recife, Rio de Janeiro, Salvador e São Luís,

Fig. 10

Thematic maps of reduction in NO₂ concentrations from March 12 to April 16, 2019 and 2020, in the metropolitan regions of São Paulo, Sorocaba, Teresina, São José dos Campos, Vitória, Brasília, Cuiabá, Petrolina,