VULNERABLE people are at risk from a moderate-to-high air pollution 'episode' in Scotland partly caused by dust from the Sahara Desert, an environmental group has warned.

The dust has dirtied cars, windows and wheelie-bins across parts of Scotland.

The Met Office says that people all over the UK will see more "blood rain" fall from the skies as a result of the record-breaking Easter weekend heatwave.

The red rain is a rare weather phenomenon, and gets its blood-like colour thanks to sand or dirt which is picked up from the desert by the wind, it then falls in the rain when showers happen.

Experts say in Scotland dust has been blown by strong easterly winds from the direction of the Sahara, along with smoke from large fires located in eastern Europe and Russia in recent days.

This has resulted in high levels of air pollution, particularly PM10 - coarse dust particles - being picked up by air monitoring stations particularly in eastern half and coastal areas.

The official Scottish Air Quality study which makes a calculation based on the highest concentration of five pollutants including nitrogen dioxide, sulphur dioxide, ozone and particulate matter, shows the highest levels of pollution are in Aberdeen City and Angus. All other areas of Scotland were at 'moderate'.

HeraldScotland:

According to the website, older people living in areas of High pollution should reduce physical exertion.

And anyone in the general population experiencing discomfort such as sore eyes, cough or sore throat should consider reducing activity, particularly outdoors.

In High and Moderate areas of pollution, adults and children with lung problems, and adults with heart problems, who experience symptoms, should consider reducing strenuous physical activity, particularly outdoors.

In Aberdeen, air monitoring equipment recorded the highest levels in Scotland, in the city’s King Street at 8am on Wednesday according to Environmental Protection Scotland.

After a similar episode in February, Friends of the Earth Scotland raised fears levels of toxic particulate matter in Scotland will be in breach of World Health Organisation and Scottish regulatory safety standards across the country.

John Bynorth, policy and communications officer at the charity Environmental Protection Scotland (EPS), said: “This appearance of sand from the Saharan desert together with the high levels of Particulate Matter and moderate levels of Ozone has been found not just in the main towns and cities on the east coast, but in Angus, Shetland, and even remoter areas of the Highlanders.

"These are places you would not normally to expect to see such pollution and highlights how Scotland has no control beyond its boundaries over trans-boundary air pollution.

“Particulate Matter is of concern for people who suffer from respiratory conditions such as asthma. We would advise anyone concerned about air pollution to check the national Air Quality in Scotland websiteto find out the levels in the areas where they live and work.

HeraldScotland:

EPS screen grab of air pollution from Sahara and forest fires

“Initial investigations into what is causing this air pollution has identified that air masses from the east, along with strong easterly winds affecting the country is blowing over polluted air from the continent.

"These strong easterly winds are blowing over smoke from large fires located in eastern Europe and Russia.

READ MORE: Glasgow 'is clogged with roads, traffic and pollution' 

“The fires and smoke in eastern Europe have been blowing over Scandinavia towards the east coast of Scotland.”

Mr Bynorth said the air mass trajectories and winds are set to change to the west on Thursday.

He added: “This should bring in cleaner air from the Atlantic and should see concentrations decrease significantly with levels generally returning to the low banding.”

EPS said other areas with high pollution readings as of Wednesday morning included Forfar, Salamander Street in Leith, Edinburgh, Hope Street in Falkirk and Cupar in Fife. There were also high levels of PM10 recorded at an air monitoring location in Broughty Ferry Road, Dundee.

Across the UK there have already been reports of the weird rain, as people have seen their cars and homes soaked by the blood rain and left with a covering of red dust.

The French areas of Brittany and Normandy have been placed on "orange" alert for pollution, due to a combination of the Saharan desert dust and local car emissions.

Saharan dust is the result of wind blowing strongly over the Sahara desert in Africa - whipping up dust and sand into the sky.  If the winds are blowing north, the dust can be carried as far as the UK and Scotland.

In order for the dust to get from up in the sky down to the ground, you need rain.