Financial Times FT.com

Skies have dimmed over most of the world during the past 35 years as a result of increasing pollution, according to a comprehensive study published on Friday in Science. The shining exception is Europe, where skies are clearer.

Scientists at the University of Maryland analysed visibility measurements over the period 1973 to 2007 from weather stations all over the world and also studied more recent satellite data. Visibility - the furthest distance a trained meteorological observer can see - is reduced by microscopic particles of soot and dust and droplets of sulphur dioxide in the air; these “aerosols” are generated by burning fossil fuels.