Evaluating Traffic-related Near-road CO Dispersions on an Urban Road During Summer Season: A Model Inter-comparison

Three air pollution models, namely the ‘California Line Source’ (CALINE4) model, the ‘Unique Dispersion Model’ (UDM) and the ‘Simplified Type Dispersion Model’ (STM) have been analyzed for assessing the air pollutant concentration at one of the most congested traffic road in the city of New Delhi. The latter two models have been developed using the most influential input parameters of CALINE4 namely traffic flow and wind-speed observed by both sensitivity analysis and regression analysis studies. The model performance have been estimated and compared statistically with the traffic emitted airborne carbon monoxide (CO), the prevalent meteorology and the temporal distribution of the monitored hourly average CO concentrations in summer time. The study has displayed that the UDM model would generate better predictions as compared to other models for different meteorological and traffic conditions. The complete study reveals that the similarity between the monitored and the modelled CO concentrations have been reasonably satisfactory for UDM and CALINE4 models. Further detailed assessment confirms that the UDM model performed superior in comparison to the CALINE4.