Page 50 - Demo

48Roadside air purifierNitrogen dioxide is harmful to humans. It undermines the lungs%u2019 defence against bacteria, making us more susceptible to lung infections and aggravating asthma. Vehicles are the main source of roadside nitrogen dioxide pollution. Both the growing number of vehicles overall and the growing number of ageing vehicles are major contributors to nitrogen dioxide pollution, causing a major air quality challenge. In collaboration with the Highways Department and the Environmental Protection Department, Prof. Lee led a research team to develop air purifiers that can be incorporated into smart lampposts to improve roadside air quality. These roadside air purifiers use a combination of physical and chemical processes, along with special nanomaterials, to clean the air. An air blower at the top of the air purifier draws contaminated air from the bottom and pushes it upward through six sets of purification modules. Seven active air purifiers were deployed at PolyU%u2019s roadside monitoring station. Within an assessment area of 944 square metres, they removed up to 16% of nitrogen dioxide, up to 10% of nitrogen monoxide, and up to 44% of fine particulate matter measuring 2.5 microns or less (PM2.5) in diameter.TAKE A DEEP BREATHDIGGING DEEPER