Development and Performance Evaluation of TiO₂–activated Carbon-based Air-purifying Paver Blocks for PM2.5 and VOC Removal

Air pollution constitutes a major environmental crisis worldwide. Day-to-day, vehicles emit harmful air pollutants, posing various hazards to both living beings and the surrounding environment. The primary air pollutants responsible for health problems in urban areas are PM2.5 (particulate matter with an aerodynamic diameter of ≤ 2.5 µm) and volatile organic compounds (VOCs). Air-purifying paver blocks are used to significantly reduce air pollutants along pedestrian footpaths. The novelty of this research lies in the combined effect of titanium dioxide (TiO2) and geopolymer-based paver block production and the implementation of an Internet of Things (IoT) system to assess their effectiveness in reducing air pollution. The effectiveness of air-purifying paver blocks incorporated with TiO₂ and geopolymer concrete for the removal of PM2.5 and VOCs under field conditions was investigated. The results indicated that the paver blocks removed approximately 70% of PM2.5 and 50% of VOCs from the ambient air. In addition, the influence of operational parameters, such as temperature, humidity, and air velocity, on the performance of the paver blocks was examined. Data obtained from the IoT monitoring system revealed that CO and CO2 levels were lower at the centre of the paver blocks and gradually increased towards their outer edges. Owing to the combined advantages of TiO₂ and geopolymer-based paver blocks, their cost is approximately 5–10% higher than that of conventional fly-ash paver blocks; however, the associated environmental benefits are substantially greater.