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Nanocoating on buildings releases potentially toxic particles to the air
May 28, 2015
Nanocoating on buildings releases potentially toxic particles to the air
Weathering and abrasion are reported to cause titanium dioxide nanoparticles to escape from a self-cleaning coating for buildings. These particles may be toxic to humans and wildlife. The researchers have developed three indicators from the test results to help predict levels of nanoparticle release from these coatings.
Photocatalytic coatings containing nano-sized particles of titanium dioxide are increasingly applied to the outside of buildings for their antibacterial and self-cleaning properties. Weathering and wear can cause them to disintegrate and there are concerns about the subsequent release of nanoparticles into the environment. Various studies have found that some types of titanium dioxide nanoparticles have damaging effects on humans and animals. For example, experiments have shown that they can damage DNA.
This study investigated weathering and wear’s effects on a photocatalytic nanocoating to help predict levels of nanoparticle release into water and air. The coating was comprised of 1.1% titanium dioxide particles by volume, which were around 8 nanometres in size.
Over a seven-month period, the researchers exposed a brick painted with the coating to UV light and water to recreate the effects of weather. At four intervals — two, four, six and seven months — they measured titanium levels in the runoff water. Titanium was measured as it is not possible to measure the relative number or percentage of titanium dioxide nanoparticles specifically. However, the coating’s nanoparticles were the only type of titanium in the experiments.
Read more at "Science for Environment Policy": European Commission DG Environment News Alert Service.
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