The Met Office said it was monitoring a cloud of sulphur dioxide moving across the UK following a volcanic eruption in Iceland.
The gas cloud apparently moved across the country early Sunday morning and has now moved towards the southeast.
The particle was released high into the atmosphere by a volcano in Iceland and is likely to have “only a minor impact on air quality near the ground,” said the meteorologist.
Sulfur dioxide is a colorless, strong-smelling gas that is commonly released during coal combustion and other refining or manufacturing processes.
If inhaled in high concentrations, the gas can cause throat irritation, nausea, stomach pain and vomiting.
The Met Office said “low levels” of the compound mean air pollution in the UK should remain low.
A Met Office spokesman said: “A cloud of sulphur dioxide emanating from the volcano in Iceland is crossing the UK high in the atmosphere and will soon dissipate to the southeast.”
“The impact of this sulphur dioxide was small because it is high in the atmosphere and has little impact on air quality near the ground.
“Low concentrations near the ground mean that air pollution remains low.
“Air pollution levels are currently low and are expected to remain so across the UK today.
“We continue to monitor all sulphur dioxide emissions from Iceland. Current forecasts suggest that there will be little impact on air pollution in the UK over the coming days.”
A volcano in southwest Iceland erupted for the sixth time since December on Thursday, spewing red lava and causing violent earthquakes.