Development of a low-cost particle capturing device for vehicular emissions: a pilot study

Urban air pollution primarily originates from vehicular emissions, which significantly contribute to deteriorating air quality in densely populated areas. While certain gaseous pollutants are partially retained by roadside vegetation, particulate matter (PM) tends to evade retention due to urban microclimatic conditions that promote deflection, settling, and resuspension. To mitigate the adverse health impacts of PM exposure, it is crucial to develop cost-effective, sustainable methods to capture pollutants at the source or near receptors. This study presents the development and evaluation of a low-cost, bio-based particle-capturing prototype designed to target vehicular emissions. The prototype consists of a cylindrical enclosure made from raw coconut husk and sugarcane pulp, tapering to a conical outlet connected to a pollutant-monitoring chamber. Performance was evaluated in an indoor environment simulating outdoor conditions under two vehicular movement scenarios: vehicles departing from a junction and cars idling at a junction. Pollutant concentrations of CO, CO₂, PM_2.5, and PM₁₀ were measured under varying turbulence intensities. Results indicated that the Single Pass Removal Efficiency (SPRE) for PM_2.5 and PM₁₀ was higher in stationary vehicle scenarios under high turbulence and in moving vehicle scenarios under medium turbulence. For gaseous pollutants, low-turbulence, stationary conditions facilitated more efficient contaminant capture. Vehicle-halting-at-junction scenario reductions ranged from 15-20% for PM₁₀, 15-45% for PM_2.5, 10-30% for CO, and 15-45% for CO₂. Similarly, vehicle-moving-at-junction scenario reductions ranged from 20-65% for PM₁₀, 15-65% for PM_2.5, and 40-55% for CO and CO₂. The findings demonstrate the potential of bio-based materials as sustainable alternatives for mitigating urban air pollution and highlight the role of turbulence dynamics in optimising the capture efficiency of particulate and gaseous pollutants.