Unveiling Seasonal Fluctuations in Air Quality Using Google Earth Engine: A Case Study for Gujarat, India

Abstract

Presently, a significant portion of the global population resides in metropolitan areas where air pollution levels are usually high. The primary objective is to utilize satellite data to identify the concentration of pollutants, unlike the traditional method which utilizes a series of ground-based detectors. The study aims to analyze the distribution of different pollutants in the air over the Gujarat state, India. The study comprised the utilization of Sentinel 5-P data sets for mapping Carbon monoxide (CO), Nitrogen dioxide (NO₂), Sulfur dioxide (SO₂), Methane (CH₄), and Formaldehyde (HCHO). Google Earth Engine platform was used for the processing of satellite imagery and maps were prepared using ArcGIS 10.3. The satellite data sets of different pollutants were processed and assessed for three seasons i.e., winter, summer, and monsoon to analyze the effect of climatic conditions as well on the concentration level over the study area. The concentration of CO ranges between 0.0295–0.0401 mol/m². The average concentration of SO₂ is 0.00047 mol/m² whereas the average concentration of NO₂ ranges from 0–0.00021 mol/m² and formaldehyde concentrations values range from 0.00015 to 0.00026 mol/m² over the year. The concentration range for methane is 1780–1940 ppb for the study area. The results exhibit that the northern part of Gujarat mainly consisting of Kutch, Banas Kantha, and Patan renders the lowest concentration of all air pollutants while the central and southern regions consisting of cities like Valsad, Surat, Bharuch, Vadodara, and Ahmedabad have recorded the peak values in all the seasons. The findings suggest that the increase in the levels of different pollutants is caused by human activities, industrialization, and urbanization.