Estimation and ground validation of CO Concentration dispersion modelling in five different road types in Makassar City

Climate change and worsening urban air quality remain critical global challenges, with transport-related emissions contributing substantially to atmospheric pollution. This study aims to examine carbon monoxide (CO) concentration values obtained from motor vehicle emission load dispersion modeling, alongside direct measurement values, in Makassar City. Direct measurements were conducted at 30 locations on different road types (6/2D, 4/2D, 4/1UD, 2/2UD, 2/1UD) to determine vehicle volume and CO concentrations. CO emission loads were calculated using the Tier 2 methodology in accordance with Ministry of Environment Regulation No. 12 of 2010, and subsequently simulated using dispersion modeling software. The findings indicated that the 6/2D type had the highest emission loads, correlating with elevated traffic volume. A comparison of CO concentration values between direct measurements and emission load modeling revealed that direct measurements ranged from 229 to 1,684 µg/m³, whereas dispersion model results ranged from 275 to 1,320 µg/m³, demonstrating a similar distribution pattern across all road types. The Paired sampel T-Test produced a significant value of 0.45 (p > 0.05), indicating no meaningful difference between measured and modeled concentrations. The findings demonstrate that the dispersion model effectively represents the distribution pattern of CO concentrations attributable to traffic activities across different road types in Makassar City. This research provides essential scientific support for urban air pollution control strategies and contributes to achieving ustainable Development Goal (SDG) 13 related to climate change mitigation.