Air pollution treatment in European urban environments by means of photocatalytic textiles

PROJECT DESCRIPTION

BACKGROUND

Air pollution from traffic is a growing problem, especially in urban areas. Photocatalytic self-cleaning and de-polluting materials using titanium dioxide (TiO2) could be a way of removing these pollutants. Titanium dioxide is used in construction materials, paints and paper manufacturing. Further testing is required to clarify the potential impacts of wider TiO2 use.

OBJECTIVES

LIFE PHOTOCITYTEX set out to assess the effectiveness of using TiO2-based photocatalytic nanomaterials in building textiles as a way of improving air quality in urban areas. This would first involve reviewing the current technologies available and identifying photocatalytic compounds that are suitable for use with textiles. The project team would then review European legislation related to the concentration of pollutants in urban environments to establish the conditions for a large-scale demonstration. Once those conditions are established, it would develop textile prototypes (awnings and wall coverings) on a semi-industrial scale. These will be tested at EUPHORE, the European photo reactor, an atmospheric simulation chamberat CEAM (Valencia, Spain). The chamber is a half-spherical Teflon bag with a confined volume of air of about 200 m3 where representative European atmospheric conditions can be simulated using natural sunlight. Field trials of the prototypes will then take place at two urban locations in Quart de Poblet, Valencia. Testing will provide information about secondary products formed when the photocatalytic textiles are used, improving understanding of the whole process and its implications. This increased understanding would allow the project team to draw up a guide that establishes a common methodology for the application of photocatalytic textiles in polluted environments. The project also intended to produce a market analysis.

RESULTS

The LIFE PHOTOCITYTEX project completed the production of textile prototypes at laboratory scale and at semi-industrial scale. These fabrics were tested in the EUPHORE chamber for different atmospheres and with different pollution levels. The prototype photocatalytic textile awning and wall coverings were subsequently installed in a road tunnel and a schoolyard in Quart de Poblet. The project team assessed their performance by means of 58 passive sampling campaigns and 5 active campaigns with additional instrumentation, both in summer and winter conditions. Results from the field trials showed that the textile prototypes reduced levels of nitrogen oxides (NOx) by 43-54% for the awnings (school) and 24-38% for the wall coverings (tunnel). In the EUPHORE chamber, the awning textiles were also found to significantly reduce the concentrations in air of Toluene, m-Xylene and 135-TMB and reduce the formation of secondary pollutants such as ozone and particulate matter in the presence of VOCs. This is an added value for the project, not foreseen in the approved proposal. The project team conducted a market analysis of the photocatalytic textiles, with the following results:

production costs: 10.27/m2 for awning and 5.20/m2 for wall covering;

breakeven point: 37 500 m2 of production; and

market prospects by 2021: 180 000 m2 of production; 1.51 million turnover; global market for photocatalytic products: $2.9 billion (by 2020). Thus the project concludes that there is a promising market for photocatalytic textiles. They can play an important role in the decontamination of polluted areas, helping to accomplish the objectives established by the Ambient Air Quality Directive (2008/50/EC). In addition to health benefits, they could also generate new employment opportunities in existing companies and foster the birth of new high-tech companies. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).