Scientists have released photographs of what they believe are volcanic glass particles from Iceland which fell on Scotland this week.
The samples were taken from a car windscreen in Aberdeen and analysed at the city's James Hutton Institute.
The images of the tiny particles were taken using a scanning electron microscope.
Scientists said it was "highly likely" the glass particles, which are part of the ash constituents, came from the Grimsvotn volcano which started erupting on Saturday.
However, they said it could not be confirmed until they received a sample from Iceland to compare the compositions.
The largest of the particles is 0.03mm across, with the smallest measuring just 0.002mm wide.
The institute also analysed samples given to them by the Scottish Environment Protection Agency (Sepa) taken in Lerwick, Shetland, which matched the particles taken from the car window.
Evelyne Delbos, the institute's head of electron microscopy, said: "We analysed the same sample on the same day from Lerwick and it had the same elemental composition.
"It is highly likely the particles came from the Grimsvotn volcano but until we have a reference sample to compare we cannot confirm."
The ash cloud left hundreds of passengers facing travel misery earlier this week when flights were cancelled when it drifted into Scottish airspace.
The James Hutton Institute was formed earlier this year from the Macaulay Land Use Research Institute in Aberdeen and the Scottish Crop Research Centre in Dundee.
It employs more than 600 scientists and staff, making it one of the biggest research centres in Europe.
In a statement on Sepa's website, the organisation said: "As with the Eyjafjallajokull volcanic eruption last year, the Scottish Environment Protection Agency has been closely monitoring the latest volcanic eruption from Iceland and the impact of the resultant ash cloud on Scotland's environment.
"Sepa is monitoring air quality, and collecting and analysing dust and rainwater samples, looking for volcanic contaminants such as iron, manganese and copper and monitoring pH and fluoride levels.
"On Tuesday 24 May a number of cars in Shetland, Thurso and Orkney were reported to have a covering of dust, suspected to be volcanic ash.
"Sepa staff used a piece of clean cloth to collect a sample of this dust from a car in Lerwick, Shetland, and sent it to Sepa's laboratory in Aberdeen for analysis."
