The catalytic jeans exhibited below show the findings of Tony Ryan and Helen Storey, who discovered that when denim is covered with tiny nano-particles of titanium dioxide, it reacts with air and light to break down harmful emissions in the air; working in the same way as catalytic converters in cars.   Pollutants most often produced by traffic and factories, such as Nitrogen Oxide are then neutralised and simply washed away when the garment is laundered.