Effect of nano cement added photocatalytic precast facade elements on atmospheric pollution-Ankara provincial example

Increasing environmental problems such as climate change, energy shortages, greenhouse gas emissions and air pollution, which have an intense impact on megacities has made it necessary to use sustainable new technologies within the discipline of architecture. At this point, the use of photocatalysts, which is one of the most promising solutions, has come to the fore. Photocatalytic oxidation technology (PCO); It is a kind of mechanism that allows photocatalysts to neutralize common atmospheric pollutants by using artificial or natural UV light. By using titanium dioxide (TiO2) nanoparticles as photocatalyst, self-cleaning and air-cleaning building materials can be produced. One of the most widely used materials in urban areas is cement-based products and photocatalytic cements have an important share in improving air quality. As a result of the inclusion of TiO2 in the cement composition and its use in urban areas and building envelopes, the photocatalysis effect can be mentioned in areas with high population density and high exhaust emissions from traffic. Within the scope of the research, the usege of photocatalytic cements in concrete-based precast elements on building facades, their advantages, pollution status according to the surface properties of the panels and air cleaning properties were examined. With the use of photocatalytic white cements, it is also possible to reduce the cooling energy and heat retention in buildings. With the scenario of using photocatalytic precast elements, which are widely used in Europe, on an urban scale, a calculation method for the reduction of existing emissions has been created. Ankara province was chosen as a model and annual emissions of different pollutant sources were given. From this point of view, the amount of photocatalytic cleaning of nitrogen oxides (NOX) per year depending on the annual construction area and the prefabrication rate in Turkey has been found. Accordingly, the photocatalytic effect ratio was calculated and it was revealed that there could be a 0.30% reduction in NOX emissions as a result of the use of photocatalytic cement in the existing precast elements for Ankara. Analyzes were formulated depending on the variables. Thus, an estimation method has been established in which the rate of photocatalytic effect can be determined depending on the ratio of precast or different materials to be used in different provinces or construction areas. It is predicted that photocatalytic materials will be an effective tool in the fight against air pollution if they are an alternative to sustainable green materials and used together with other environmentally sensitive technologies in the discipline of architecture.