{"id":24158,"date":"2018-05-07T07:00:13","date_gmt":"2018-05-07T05:00:13","guid":{"rendered":"https:\/\/breinco.com\/breincosmartblog\/smart-urban-planning-controlled-pollution\/"},"modified":"2018-05-07T07:00:13","modified_gmt":"2018-05-07T05:00:13","slug":"smart-urban-planning-controlled-pollution","status":"publish","type":"post","link":"https:\/\/breinco.com\/en\/breincosmartblog\/smart-urban-planning-controlled-pollution\/","title":{"rendered":"Smart urban planning: controlled pollution"},"content":{"rendered":"

Smart urban planning: controlled pollution<\/h4>\n

The photocatlysis<\/h4>\n

Today, there is broad consensus among the sectors involved regarding the strong growth that the photocatalytic industry will experience in the coming years. In fact, photocatalysis<\/strong>, based on the use of semiconductor materials, has numerous applications in fields such as improving air and water quality, reducing building maintenance and conservation costs due to its self-cleaning capacity, health and general well-being due to its biocidal and organoleptic effect, and energy. However, this promising technology is not well known either by public and private infrastructure managers or by the general public. In the field of environmental pollution, a stronger legislative framework, with greater regulation to eliminate fraudulent products from the market, as well as greater knowledge of this technology among technical specifiers, would have a positive impact on the application of photocatalysis.[1]<\/p>\n

\u201cAirClean\u00ae<\/a> reduces quickly and effectively harmful NO2 (nitrogen dioxide), thus helping to comply with established limits. The basis of the effectiveness of AirClean\u00ae pavements and fa\u00e7ades is photocatalysis: they decontaminate the air, destroy dirt and prevent the growth of microorganisms.\u201d<\/p><\/blockquote>\n

Gemma Pag\u00e8s<\/a>. Technical Architect. Breinco<\/strong><\/p>\n

\"airclean <\/p>\n

Photocatalytic concrete<\/strong><\/h4>\n

Air purification through photocatalysis consists of several steps: under UV light, the photoactive TiO\u2082 on the material surface becomes activated. Subsequently, pollutants are oxidised<\/strong> due to the presence of the photocatalyst and are deposited on the material surface. Finally, they can be removed by rainwater or washing.<\/p>\n

Photocatalysis using titanium dioxide<\/strong> as a catalyst is a rapidly developing field in environmental engineering, as it has great potential to address increasing pollution. In addition to self-cleaning properties, it has been known for almost 100 years that titanium dioxide acts as a photocatalyst capable of decomposing pollutants under UV radiation. (4)<\/p>\n

The use of TiO\u2082 in its photoactive anatase crystalline phase for air purification originated in Japan in 1996.(7) Since then, a wide range of products has appeared on the market for both indoor and outdoor applications.<\/p>\n

Regarding traffic emissions, it is important that exhaust gases remain in contact with the active surface for a certain period of time. Street configuration, traffic speed, and wind speed and direction<\/strong> all influence the final in-situ pollutant reduction rate.<\/p>\n

Applications<\/strong><\/h4>\n

Photocatalysts, typified by TiO\u2082, are defined as substances that promote reactions through light absorption without being altered before or after the reaction. When titanium dioxide is exposed to a light source, such as sunlight or fluorescent light<\/strong>, it shows both oxidative decomposition and superhydrophilic properties, which can be effectively used for deodorisation, antibacterial action, pollution prevention (NOx and VOC removal), anti-fogging, dirt removal and sterilisation.<\/p>\n

\"photocatalysis <\/p>\n

Photocatalysis in a concrete paver<\/h4>\n

In a concrete paver, anatase is added in the wear layer of the pavers, approximately 4\u201310 mm thick. The presence of TiO\u2082 throughout this layer means that even if surface wear occurs, for example due to traffic or weathering, fresh TiO\u2082 remains available to maintain photocatalytic activity (unlike the abrasion of a paint or coating layer).<\/p>\n

The use of TiO\u2082 in combination with cement leads to the transformation of NOx into NO\u2083, which is absorbed on the surface due to the alkalinity of concrete. A synergistic effect is therefore created by the cement matrix, which helps effectively capture reactive gases (NO and NO\u2082) together with the formed nitrate salt. Subsequently, the deposited nitrate can be washed away by rainwater or cleaning. These nitrates do not represent a real threat to groundwater contamination, as the resulting concentrations are very low.<\/p>\n

According to the Air Quality Report 2015 by Ecologistas en Acci\u00f3n:<\/a><\/em><\/h3>\n