Impact of traffic conditions on PM 2.5 concentrations at two distinct traffic junctions in Bangkok Thailand

Abstract

The impact of traffic flow on PM₂.₅ emissions at two types of different traffic junctions were examined, at Phathum Wan intersection site (13.44’46 "N, 100.31’51" E) and Odeon Circle Yaowarat roundabout, site (13.44’13 "N, 100.30’46" E). Ambient PM₂.₅ concentrations was collected 12 hours/day within working hours day-time. While the traffic flow and number of vehicles were recorded by video camera simultaneously. The relationship between concentration of PM₂.₅ and traffic conditions were compared between these two sites. At Phathum Wan intersection, the linear regression is significantly related between PM₂.₅ and traffic flow and number of vehicles, r = 0.84. However, at the Odeon Circle Yaowarat with high traffic flow, r = 0.48, showed a moderate level in the same direction. The concentration of PM₂.₅ in ambient and the emission of the passenger-car and medium-utility vehicles-car,van (PC-MUV) and three-wheel-auto rickshaw (3WH) are associated with PM₂.₅ levels, at Phathum Wan intersection.