It's been a dusty start to the Easter weekend for parts of Europe with a large plume of Saharan dust moving up over the continent.

The dust cloud has smothered some parts of Germany, France and Switzerland with a rare haze of dust coming up all the way from the Saharan Desert.

Between 60 and 200 million tonnes of mineral dust are swept up from the Sahara each year. While the larger particles quickly fall back down to Earth, the smallest particles can sometimes travel for thousands of kilometers.

Switzerland's airCHeck monitoring service flagged high levels of pollution in a corridor stretching from the southwest to the northeast of the country.

Local authorities in France announced that the air pollution threshold had been passed in some areas. The department of Herault, on the Mediterranean coast, warned residents against intense physical activities.

As in other parts of the world, the wind can blow strongly over deserts - whipping up dust and sand high into the sky. If the winds in the upper part of the atmosphere are blowing north, the dust can be carried as far as the Ireland and the UK.

Once it is lifted from the ground by strong winds, clouds of dust can reach very high altitudes and be transported worldwide, covering thousands of miles.

In order for the dust to get from up in the sky down to the ground, you need something to wash it out of the sky - rain. As raindrops fall, they collect particles of dust on the way down. Then when the raindrops land on something and eventually evaporate, they leave behind a layer of dust.

Saharan dust is relatively common in the Ireland and the UK often happening several times a year when big dust storms in the Sahara coincide with southerly wind patterns. In certain weather situations, Saharan dust can also affect air pollution and pollution levels.

Midweek this week people may see traces of the dust after any showers.

The levels of dust in the atmosphere are not forecast to be as high or big as parts of Europe this weekend.