Emission load distribution and prediction of NO2 and PM10 using ISCST3 and CALINE4 line source modeling

Mysore district is one of the tourist destinations in Karnataka, India, with a population of about 10.25 lakhs. In all category of vehicles, 2-wheelers (2W) constitute more than 50 %. Vehicular count studies showed a maximum number of vehicles during peak traffic hours (7:00-11:00 hrs. and 18:00-22:00 hrs.). The maximum traffic count was observed for 2W (51-56%) followed by 4W (19-28%), LDV (light-duty vehicle), HDV (heavy-duty vehicle) and 3W. However, the percentage contribution of NO2 and PM10 emission factor showed, a maximum of HDV (75-89%) followed by LDV, 2W, 3W, and 4W. Emission loads for CO and NO2 pollutants were found to be high at link 1, 2, 5, 6, 12 and 13 due to heavy traffic densities. However, emission loads for PM10, PM2.5, and SO2 were notices to be very less in all the links. During winter season Industrial source complex short-term model 3 (ISCST3) and California line source model 4 (CALINE4) predicted NO2 concentrations were found to be ranging from 9–25 μg/m3 and 10–40 μg/m3, respectively. However, PM10 concentrations were found to be 18–43 μg/m3. The maximum concentration was found near to Receptors (R1-3), which may be due to maximum vehicular density and downwind to the pollution sources. NO2 and PM10 predictions made by ISCST3 and CALINE4 model showed a significant variation. It was also observed that CALINE4 model was not applicable to predict pollutant with lower concentrations.