Characterization of Diurnal Ozone and Its Precursors Variation in Bogor Area, West Java, Indonesia

Abstract

This study analyzes the diurnal variation of ozone (O₃) and its precursors: nitric oxide (NO) and nitrogen dioxide (NO₂), in the Bogor area, using observational data from the BMKG Citeko and CCROM-SEAP IPB monitoring. The research aims to characterize temporal patterns of ozone formation in urban (Baranangsiang) and rural (Citeko) locations, and to examine the influence of precursor availability and meteorological factors. Average hourly concentration data were evaluated, followed by correlation analyses to assess the relationships between ozone and precursor gases. Results showed that ozone levels in both locations follow typical photochemical behavior, low in the early morning, rising as solar radiation increases, and peaking in the afternoon. Ozone concentrations in the dry season (September) were notably higher than in the rainy season (December), reflecting the influence of solar radiation intensity and cloud cover. Citeko consistently recorded higher ozone concentrations than Baranangsiang, despite lower NOx levels, suggesting a stronger influence of transported or background ozone in rural areas. Correlation analysis revealed a strong negative relationship between ozone and NO in Baranangsiang (R² = 0.86), while weaker correlations were observed in Citeko. Temperature also displayed a positive correlation with ozone (R² > 0.8), emphasizing its key role in photochemical processes. These findings highlight the importance of precursor emissions, meteorology, and regional transport in shaping ozone dynamics in the Bogor region.