De-polluting, self-cleaning coating compositions are disclosed which comprise an organic binder having dispersed therein photocatalytic titanium dioxide particles substantially in anatase form which have an average crystallite size between about 1 nm and about 150 nm and which preferably have photocatalytic activity in the presence of visible light. Advantageously, the coatings of the invention do not require pre-activation to achieve high initial photocatalytic activity against pollutants in the air, such as NOx compounds.