Environmental Science: Nano Blog

A study by scientists in France and China has raised questions about the effectiveness of paints formulated to combat air pollution. Whilst the paints decompose some pollutants, the research revealed they also generate and release other toxic compounds.

Urban air pollution is a common problem in many of the world’s cities; vehicles and power stations are the primary culprits. Titanium dioxide nanoparticles, when exposed to UV light, can oxidise organic compounds in the air. When added to paint, they present a quick fix for reducing air pollution. However, the overall improvement to air quality is dubious.

a) Photocatalytic paints contain titanium dioxide nanoparticles. b) Ultraviolet radiation activates the titanium dioxide nanoparticles, which degrade ambient VOCs, as well as the organic matrix of the paint, releasing new VOCs into the air. c) As the paint ages, it releases titanium dioxide nanoparticles too. Source: © Royal Society of Chemistry

So says Sasho Gligorvoski, from the Chinese Academy of Sciences, and his team who have found that photocatalytic paints release significant quantities of nanoparticles and volatile organic compounds (VOCs) over their lifetime. This is especially problematic indoors, where the chemicals accumulate over time.