Simulation of Submicron Particulate Matter (PM1) Dispersion Due to Traffic Rerouting to Establish a Walkable Cultural Tourism Route in Ratchaburi’s Old Town, Thailand

Abstract

Cultural tourism helps preserve cultural heritage and provides economic opportunities for local communities. A walkable cultural tourism route has been developed for the old town of Ratchaburi, Thailand. Here, we assessed changes in PM1 after cars were banned from the walkable tourist route. A near-roadway dispersion model, R-LINE, was evaluated and used to explore the base case (BC) and two scenarios, S1 and S2. In the BC, road traffic activities reflected the current situation; in S1, all vehicles were banned from the walkable route; and in S2, all drivers were encouraged to park their vehicles outside the study area. The road traffic activities in the study area were observed and used to calculate the PM1 emission rates for the model inputs. The model was capable of simulating PM1 concentration, especially the average PM1 concentration over the monitoring period. An increase in PM1 concentration was seen at the main road in S1 due to the increased traffic volume that had been redirected from the walkable route, with an increase in daily PM1 of 4.5% compared to BC. S2 showed a decrease in the PM1 concentration of 8.9%. These findings suggest the need for traffic mitigation measures prior to initiating a walkable route for cultural tourism, to meet environmental sustainability requirements.