Estimating Emission Load from Road Transportation within the Bhaktapur Municipality, Nepal

Vehicular emissions have been playing a pivotal role in deteriorating air quality in many urban parts of Nepal causing adverse impacts upon the health of commuters and pedestrians attributed to severe respiratory diseases. Primary data such as the number of vehicles (N) were obtained using two-hour peak (8 am to 10 am) and two-hour nonpeak (1 pm to 3 pm) count, after which average annual vehicle kilometer (VKT) and fuel economy (F) required for emission load estimation were obtained from vehicle survey using the simple random sampling method, sampling size taken statistically under 5% margin of error. Secondary data in this study include emission factors and derived equations from a published article. The vehicular emission load of Bhaktapur Municipality were found to be 3,310 tons/year including CO₂, CO, NOx, HC, and PM₁₀ of which CO₂ accounts for 94.36% of total emissions followed by CO (4.39%), HC (0.72%), NOx (0.35%), and PM₁₀ (0.18%), respectively. Significant positive correlation was found (r = 0.92, p=0.002) between CO₂ and PM₁₀ (r = 0.87, p=0.009), between CO₂ and NOx (r = 0.90, p=0.004), between CO and HC (r = 0.74, p=0.05), and between NOx and PM₁₀, respectively. The scenario analysis shows that the introduction of electric vehicles at different rates within the municipality can reduce the emissions to a significant amount. Exponential growth in vehicular gaseous pollutants potent to jeopardize the environment and welfare can become inevitable in the future if clean energy technology is not promoted early.