PARIS: Fog, mist and haze in Europe have declined over the last three decades, a trend that may have stoked regional warming and ironically could be
linked to better air quality, a study published says.

From 1978-2006, temperatures in parts of Europe rose above the global land average, with prominent increases in the north, centre and eastern parts of the continent.

As much as 20% of Europe\'s warming during this time, according to the study, can be pinned on a reduction in fog, mist and haze, which — because they are white — reflect solar radiation and thus keep the ground cool. In eastern Europe, the decline in fog, mist and haze could account for 50%, the paper believes.

The authors, led by Robert Vautard of France\'s Atomic Energy Commission (CEA), pored over data from 342 weather stations around Europe.

They found that over nearly 30 years, the number of days categorised as having restricted visibility fell by half. These categories were determined by ranges of visibility at 2km, 5km and 8km.

The phenomenon is closely linked to falling levels of atmospheric sulphur dioxide (SO²), a byproduct of burning oil and coal that causes notorious \"acid rain” that damages forests and lakes. The temperature rise has been especially perceptible in Eastern Europe, where the end of the Communist system closed down innumerable sources of coal pollution. However, the SO² cleanup is now largely tapering off.

This means the fog reduction will probably stop and \"the warming trend in Europe will not be so large in the coming years,\" Vautard said.