Impact of meteorological factors and ventilation coefficient on diurnal and seasonal variations of tropospheric ozone in Bangalore
Hulivahana Nagaraju Sowmya, B.S. Surendra, Archudha Arjunasamy, E. K. Reshma, M. Bhaskar, K. Kavitha, G. P. Shivashankara, H. K. Ramaraju
Abstract
The reported study examines the diurnal and seasonal variations of tropospheric ozone and its precursors in Bangalore, India, from January to December 2020, and explores the impact of meteorological parameters and the ventilation coefficient (VC) on ozone levels. Tropospheric ozone, a significant secondary pollutant, poses a major environmental and health challenge in urban areas. The study focuses on ozone, nitrogen oxides (NO and NO 2 ), Sulphur dioxide (SO 2 ), and carbon monoxide (CO), revealing that ozone peaks in the early afternoon due to solar radiation, while precursor pollutants show morning and evening peaks linked to traffic emissions. Higher ozone levels occur in winter (due to reduced boundary layer height) and summer (due to increased photochemical activity), while the monsoon period shows the lowest levels due to the washout effect. The VC values are generally higher during the day (587 m 2 /s) compared to night (246 m 2 /s), with the highest recorded in summer (1,935 m 2 /s) and the lowest in the post-monsoon season (209 m 2 /s). Higher VC enhances pollutant dispersion, while lower VC leads to accumulation. However, surface ozone concentrations increase with higher VC due to photochemical processes. The findings highlight the complex interplay of meteorology, emissions, and boundary layer dynamics, informing strategies for urban air quality management.