Spatio-temporal variation and trend analysis of ground-level ozone in major Indian metropolitan cities: A geospatial approach

Abstract

Air pollution refers to any chemical, physical, or biological contamination that contaminates an interior or outdoor environment and modifies the intrinsic qualities of the atmosphere. It can be produced by natural or anthropogenic activities. Among those pollutants mentioned by the World Health Organization (WHO), ground-level ozone, also known as tropospheric ozone, possesses a significant impact on human life. The current study was developed in response to the need to study ground-level ozone concentrations around India and metropolitan cities. The spatiotemporal variation across India was analyzed using geospatial methods. Using trend tests, trend analysis of the main metropolises in Bangalore, Chennai, Delhi, Hyderabad, Kolkata, and Mumbai was presented. 18 years of data (2005–2022) from the Ozone Monitoring Instrument (OMI) were used to conduct the test. According to geospatial research results, the northern region of India has a higher concentration of ozone than other locations. Delhi has a higher ozone rate than other metropolitan cities, ranging from 0.1219 to 0.1567 mol/m², followed by Kolkata (0.1085–0.1418 mol/m²). In these cities, summertime is often the time of year when the ground-level ozone concentration is at its maximum. Trend analysis using the Mann-Kendall and modified Mann-Kendall tests from 2005 to 2022 shows that the concentration increases with each year that goes by, even though there isn't a significant trend (p < 0.05) across all of the monthly, seasonal, or annual periods. The research identifies high ozone areas and seasons, guiding policies, health advisories, urban planning, and accurate pollution forecasts.