the effects of highway environmental conditions on photocatalytic pavements ability to reduce nitrogen oxides

Nitrogen oxides (NOx) emitted from vehicle exhaust are associated with negative health impacts and are a precursor to ozone. Self-cleaning, air-purifying concrete pavement is a rapidly emerging technology that can degrade pollutants such as NOx through heterogeneous photocatalysis. Although this technology has the potential to support environmentally friendly road infrastructure, a number of design and operational parameters may affect its effectiveness and thus need to be evaluated. The goal of this study was to measure the NOx reduction efficiencies from photocatalytic pavements under various environmental conditions common to highways. To achieve this goal, the objectives were to: (a) evaluate the influence of photocatalytic layer design and operating parameters on the efficiency of photocatalytic concrete pavement; (b) measure the impact of mixed pollutants on NOx reduction efficiency; and (c) measure the impact of roadway contaminants on NOx reduction.