Spatiotemporal Analysis of Air Pollution by NO2 in Urban and Rural Areas of Brazil Using Google Earth Engine and R

Abstract

Remote sensing has notably advanced in terms of the information that can be extracted from generated products. The combined use of different sensor systems proves effective in detecting environmental changes and reducing uncertainties about where significant atmospheric pollutant emissions occur. This study aimed to analyze the spatiotemporal variation of atmospheric pollution by NO₂ in urban and rural areas of the states of São Paulo, Rio de Janeiro, and Minas Gerais, Brazil, from September 2023 to September 2024. Tropospheric NO₂ data were collected using the TROPOMI sensor on the Sentinel-5P satellite. The results indicated that urban areas exhibited the highest average levels of atmospheric NO₂ pollution. In the metropolitan region of São Paulo, the average atmospheric NO₂ concentration was 1.90E-04 mol.m^-2, followed by the metropolitan region of Rio de Janeiro at 1.10E-04 mol.m^-2 and the metropolitan region of Belo Horizonte at 0.83E-04 mol.m^-2. In rural areas—specifically agricultural and pasture regions—the highest daily average of atmospheric NO₂ pollution was recorded in São Paulo at 1.50E-04 mol.m^-2, followed by Rio de Janeiro at 0.94E-04 mol.m^-2 and Belo Horizonte at 0.66E-04 mol.m^-2. From June to August 2024, elevated levels of NO₂ air pollution were observed. This study concludes that metropolitan regions have higher levels of NO₂ pollution compared to rural areas in all three states of Brazil. The burning of fossil fuels in industries, emissions from motor vehicles, and urban waste are likely contributing factors to the higher pollution levels in metropolitan areas compared to rural regions.