Study on Quadrature Experiment Design and Control Measures for On-Road Particulate Matter Emissions

Particulate matter (PM) poses a serious hazard to the health of dwellers. In order to investigate the relationship between PM concentration and its influencing factors, a quadrature experiment based on multi-factor sensitivity analysis was designed. The source strength of PM was estimated, and a discrete phase model was developed. The continuity, momentum, turbulence, and component transport equations were addressed to assess PM concentration at the height of 1.5 m above the ground level. The Reynolds stress model combined with the discrete phase model was used to calculate the PM trajectory in the air flow field. The results indicated that (1) PM concentration is the lowest under free flow, followed by slightly congested flow, moderately congested flow, and severely congested flow. PM_2.5 concentration on the leeward side under four traffic flow statuses is 3.73, 4.74, 5.68, and 7.00 ug/m³, respectively. In the same way, variation exists on the windward side of PM_2.5 and PM₁₀ concentration. (2) PM concentration will be a significant drop if taxis and cars are reduced by 50% and passengers are transferred to buses. And it will be the lowest if the passengers are transferred to electric vehicles. PM pollution caused by automobile exhaust will be less and less with the increasing use of electric vehicles and buses. (3) Within the range of observed vehicle speed, PM concentration is the highest under the speed of 35–40 km/h, followed by 40–45 km/h and 45–50 km/h. The increase in vehicle speed will bring a drop in the PM_2.5 concentration.