Prediction of CO concentrations from road traffic at signalized intersections using CAL3QHC model: the Khon Kaen case study

Based on the US EPA air pollution model, CAL3QHC version 2.0 was applied to predict carbon monoxide (CO) concentrations from road traffic at three signalized intersections in Khon Kaen province. Four data groups required by the model, namely site parameters, traffic parameters, meteorological parameters and emission parameters were collected at each intersection and have been used as the inputs to the model. The prediction results were compared to the measurement. The results showed that the predicted CO concentration variations corresponding mostly to the measurement except at some hours when there was not good agreement due to an extreme upwind location of receptor, low wind speed, raining period, other out-sources of CO concentration such as another near intersection and parking lot. However, this study shows that the CAL3QHC model can be applied to predict CO concentration in the environmental condition of Thailand quite well. Moreover, the model might be used as a tool for assessing traffic air pollution at roadway intersection as well as for air quality management.