Iceland volcano may have caused Edinburgh sulphur dioxide spike

Eruptions on the Reykjanes Peninsula have been taking place since December last year

A volcanic eruption in Iceland may have caused an “unprecedented” spike in sulphur dioxide levels in Edinburgh.

Experts believe the non-explosive fissure on the Reykjanes Peninsula caused quantities of the pollutant in the Scottish capital’s atmosphere to reach levels not seen since the 1970s.

It is thought strong winds brought gases released in the volatile geothermal event to the city on 31 May.

Researchers at the UK Centre for Ecology and Hydrology (UKCEH) said there was no danger to the public, but described the incident as “extremely unusual”.

Readings from St Leonard’s Street in the city’s Southside two days after the explosion, which took place about 850 miles away on 29 May, found 1,161 micrograms of sulphur dioxide (SO2) per cubic metre of air.

By comparison, the reading for an average day is around 0.5 micrograms – about 2,300 times lower.

The Scottish Environment Protection Agency (Sepa) also recorded increased SO2 levels on the Isle of Lewis on 30 May.

UKCEH’s senior air pollution modeller, Dr Massimo Vieno, said any damage to the environment was likely to have been “minimal”.

He said: “This was an extremely unusual event that happened for a very short period of time.

“We basically had a large explosion in Iceland, which combined with exactly the right configuration of wind to bring the plume from the Reykjanes Peninsula to Scotland and to Edinburgh specifically.

“It is a very unique event”.

Modelling data showed an intense spike in the gas over the city on 31 May

The eruption was the fifth to take place on the peninsula, near the town of Grindavik, since December 2023.

They were preceded by frequent and intense earthquakes in the region.

Volcanic activity has left much of the town deserted and many inhabitants evacuated due to fears over the impact of the series of eruptions.

SO2 is one of the most common gases emitted during geothermal events.

Some eruptions release enough of the gas to affect the global climate, however the current series have not reached anywhere near those levels.

UKCEH said it did not pose any significant health risk.

Dr Marsailidh Twigg, atmospheric chemist at UKCEH, said the last time SO2 quantities of that level were recorded was during the 1970s when heavy industry dominated the Scottish landscape.

“We have seen a huge reduction in the amount of pollutants coming from factories and mining since then,” she said.

“It has fallen by about 98% so to see it back up at that level is unique”.