The Health Protection Agency has reassured people in the UK that ash from the volcanic eruption in Iceland will not cause “serious harm”.
The ash is falling towards the ground in some areas of the country and was predicted to reach Scotland first before travelling south.
The Health Protection Agency said the ash may irritate people suffering with respiratory problems, but otherwise should not cause any serious harm.
It urged people to carry medication and inhalers with them if they had conditions such as chronic bronchitis or asthma.
It advised people who experienced symptoms to “limit their activities outdoors” or return home. Symptoms may include itchy or irritated eyes, sore throat, dry cough or runny nose.
But the Met Office said any ash that did reach ground level would be barely visible and the public should not be concerned.
The HPA said weather patterns indicated a “small fraction” of the volcanic plume in the UK’s airspace, which could include low levels of sulphur dioxide, was likely to reach the ground.
In a statement, the HPA said: “Those with existing respiratory conditions such as chronic bronchitis, emphysema and asthma may notice these effects more than others and should ensure they have any inhalers or other medications with them.
“Any such health effects are likely to be short term. The Health Protection Agency, Health Protection Scotland and the Met Office will continue to monitor the situation and issue any further advice or updates as necessary as the weather changes.”