Scotland’s most polluted street has seen a significant decrease in pollution following the introduction of the controversial new Low Emission Zone. 

On Thursday Glasgow became the first Scottish city, ahead of Edinburgh, Dundee and Aberdeen, introduce an LEZ which runs from the River Clyde in the south, High Street/Saltmarket in the east and the M8 to the north and west, and came into force for private vehicles.

Data from the first 24 hours shows that levels of the particulate nitrogen dioxide on Hope Street have been cut by over a third as a result of measures imposed by Glasgow City Council, which means they now fall within the UK government guidelines. 

The LEZ in Glasgow aims to create “cleaner and more breathable” air in the city by restricting older vehicles from the zone and issuing them with a £60 fine if they do.

The zones heavily affect owners of diesel vehicles, with a ban on cars built before 2014. This is because, without the filter that stops the emission of particulates in newer models, they omit the most particulates and nitrogen oxides, which contribute to up to 36,000 premature deaths in the UK every year.

In 2013 the World Health Organisation officially categorised nitrogen oxide as a cause of lung cancer.

As such in 2021 WHO set updated guidelines in 2021, with an ambitious  recommendation that in a 24-hour period, the level of nitrogen dioxide should not exceed 25 μg/m3 average. 

Despite the introduction of LEZ this health guideline has still not been met in Glasgow. On the first day of LEZ the average over the 24-hour period 35.1 μg/m3. 

However, the UK government's National air quality objectives sets a target below the WHO guidance at 40 μg/m3, in line with our period EU obligations, which has been met by the city in the first 24 hours. 

This data has been captured on Hope Street adjacent to Glasgow Central Station, an area that is subject to frequent congestion during peak traffic periods.

READ MORE: Glasgow air quality meets targets. Should LEZ be scrapped?

On the day prior though, before the introduction of LEZ the rate of nitrogen dioxide was double the WHO guidelines at 55 μg/m3. 

This means that there has been a noticeable impact in a short space of time, with a decrease of 27% following the introduction of the guidelines. 

Using the data from between 6 am and 9 am, the peak for nitrogen dioxide levels in the city, on the days proceeding and the first 24 hours of LEZ it can be seen that the new restrictions are having had a considerable impact during the morning commute. 

READ MORE: Glasgow's Low Emission Zone: What happened on day one of LEZ?



Comparing 9am on Tuesday this week and 9am on June 2, the second day of LEZ being in full force, there is a 345 reduction in the levels of nitrogen dioxide on Hope Street in Glasgow City Centre. 

Before the pandemic, concentrations of nitrogen dioxide from this monitor on Hope Street in Glasgow averaged 50% more than the safe legal limit. However, this was the only one monitor in Scotland where levels regularly exceeded the limit.

The average nitrogen dioxide levels on Glasgow High Street in the week leading up to LEZ 27.1μg/m3, still exceeded the health recommendations set by WHO, but well within the UK guidelines. 

The effect of air pollution on health in the city was highlighted by Gareth Brown, Chair of Healthy Air Scotland and Policy and Public Affairs Officer, Asthma + Lung UK Scotland saying: “With 1 in 5 Scots developing a lung condition like asthma and chronic obstructive pulmonary disease (COPD) in their lifetime, for them, air pollution can trigger life-threatening asthma attacks and flare-ups.  

“Air pollution in Glasgow is shockingly 4.5x World Health Organisation (WHO) levels, so it is clear that we need to make tackling air pollution a national priority with Low Emission Zones just the start.

Glasgow’s low emission zone launch went ahead despite an eleventh-hour court challenge brought by a local business.

Less than 24 hours before enforcement was set to begin in an area of Glasgow city centre, a ruling by the Court of Session in Edinburgh could have put a temporary halt to the scheme.

A local motor trade repair firm from the Townhead area of the city, which sits inside the zone, initiated court action claiming the move will put them out of business

Patons Accident Repair Centre, a 60-year-old firm, said the LEZ could wipe out more than one-third of its business as it deals with a high volume of non-compliant vehicles.

“Our cities must be redesigned to be far healthier places, where people can walk and cycle and not forced to breathe in toxic levels of air.”

A council spokesperson said: “Glasgow’s LEZ was declared in respect of exceedances of the legal objective for annual mean nitrogen dioxide - a harmful air pollutant linked to a variety of health conditions.

“Restricting access by those vehicles which contribute disproportionately to emissions from the area where air pollution levels are the highest, is a vital step in improving air quality and the health of all those who use the city centre.

“Air pollution levels are highly variable and dependent on a number of contributing factors, including weather patterns. It will therefore be some time before the benefits of the LEZ can be reported, particularly as the main expected benefit relates to the long-term annual average pollution concentrations.

“Air quality is subject to statutory annual reporting, as is any operational LEZ, and the impact of the zone will be fully considered in these reports.”