Abstract Ground-level ozone (O₃) is a secondary pollutant formed through photochemical reactions of NOₓ and VOCs under solar radiation and is a major component of urban smog (Seinfeld & Pandis, 2016). The World Health Organization identifies ozone exposure as a significant risk to respiratory health and premature mortality (WHO, 2021). In rapidly urbanizing Indian megacities, increasing vehicular and industrial emissions have intensified ozone formation. This study assesses spatial and temporal trends of O₃ across major monitoring stations in Mumbai, Maharashtra, during 2016–2024. Annual average ozone data were analyzed using the non-parametric Mann–Kendall test to detect monotonic trends (Hirsch et al., 1982). Results reveal spatial variability in ozone concentration across southern, central, western, northern, and eastern zones of the city. Among nine stations, only Bhandup shows a statistically significant decreasing trend at the 5% level. Other stations exhibit weak increasing or decreasing tendencies that are not statistically significant. The findings reflect the influence of coastal meteorology, emission intensity, and land-use patterns on ozone dynamics. The study provides scientific evidence to support urban air quality management and policy planning in Mumbai.
Ravindra Sudam Bhagat (Sat,) studied this question.