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

Urban air pollution originates from multiple sources, with vehicular emissions playing a predominant role. These emissions are rapidly dispersed across roadways, while certain gaseous pollutants are restricted by roadside vegetation. However, particulate matter (PM) is not readily retained by plants due to microclimatic conditions at the urban scale, leading to processes such as deflection, settling, and re-suspension. To minimize the adverse health effects associated with particulate exposure in ambient environments, it is essential to develop cost-effective methods for capturing airborne particles at the source, along their pathway, or at the receptor. In the present study, a low-cost particle-capturing prototype has been developed using bio-based materials to specifically target vehicular emissions. Raw coconut husk and raw sugar cane pulp were used in a cylindrical enclosure which has been tapered to a conical outlet which leads into a chamber where the air pollutants are monitored using a device. The prototype was evaluated in an indoor environment designed to simulate outdoor conditions within a controlled setting. Two vehicular movement scenarios were investigated: Vehicles moving from a junction Vehicles halting at a junction. Pollutant concentrations, including CO, CO₂, PM₂.₅, and PM₁₀, were analyzed under varying turbulence conditions induced by the pollutant source. The study revealed that for PM₂.₅ and PM₁₀, Single Pass Removal efficiency [SPRE] was observed in the stationary vehicle scenario under high turbulence, whereas in the moving vehicle scenario, SPRE occurred under medium turbulence conditions. For gaseous pollutants (CO and CO₂), the stationary vehicle scenario with low turbulence facilitated more effective pollutant capture. Broadly, for Particulate matter, the reduction has varied between 15% to 20% and 12% to 20% for PM ₁₀ and PM _2.5 respectively. Additionally, for the gaseous pollutants the percentage reduction varied between 50% to 75% and 20% to 50% for CO and CO ₂ respectively. These findings highlight the significance of turbulence and vehicular movement in determining pollutant dispersion and capture efficiency. The study highlights the potential of bio-based materials in developing cost-effective solutions for urban air pollution control while future work is needed for improving particulate removal efficiency in the field.