High particulate matter levels recorded in Glasgow

Levels of particulate matter in the Glasgow area were recently monitored as ‘high’ according to a report published on Tuesday (18 December), writes Michael Holder

High levels of particulate matter were recorded in Glasgow last week due to cold and dry weather conditions in Scotland, according to a briefing on the Scottish Air Quality website on Tuesday (18 December).

Moderate levels of nitrogen oxide were also found at two sites in Glasgow — Byres Road and Paisley central road — during the period that was monitored, from 11 to 12 December.

Glasgow city council’s map showing air monitoring sites in the city

The short report, ‘Particulate Matter pollution episode measured in Greater Glasgow urban area’, was published as an explanation for the unusually high concentrations of both PM10 and PM2.5 monitored in Scotland last week.

High levels of particulate matter can cause respiratory health problems and worsen the symptoms of lung or heart disease.

The report was compiled and written by David Hector, an air quality consultant at global environment and sustainability firm Ricardo-AEA.

Although particulate matter concentrations across Scotland were generally placed in the ‘moderate’ banding, busy roadside sites in Glasgow on Hope Street and Dunbarton Road saw concentrations in the ‘high’ banding. Levels of air pollution across Scotland have since returned to the ‘low’ banding.

Air pollution levels in the UK, including particulate matter, are monitored using the index approved by the Committee on Medical Effects of Air Pollution Episodes (COMEAP). This system uses a 1-10 index, with monitored levels of air pollution from 1-3 considered ‘low’, 4-6 ‘moderate’, 7-9 ‘high’ and pollution levels reaching 10 considered ‘very high’.

Weather conditions

The report states that the episode in Scotland was the result of particularly cold and dry weather conditions with high pressure, and that the sources of the pollution were most likely a combination of localised traffic, industrial processes and domestic fuel burning in the cold temperatures.

Regarding the weather conditions at the time, Mr Hector’s report states: “Weather conditions over the 11 and 12 December, and leading up to this time, were dominated by a high pressure system and air masses sourced from the Arctic and Scandinavia. Air masses from this direction normally bring in clean air, however, the high pressure system created very cold and dry conditions with temperatures staying around or below freezing throughout both days. It also created very little or no breeze and large pockets of freezing mist. These very poor pollution dispersion conditions caused pollutants such as particulate matter to re-circulate and stagnate close to their source. This in turn caused pollution levels to increase over a relatively short period of time.”

However, only in Glasgow were high levels of particulate matter and moderate levels of nitrogen oxide monitored during this period, which the report states is likely due to the size of the urban area and the number of sources of pollution within it.

According Mr Hector’s report: “These prevailing weather conditions affected the majority of Scotland, however, it was only in the Greater Glasgow Area that Moderate and High pollution levels were measured. This was likely due to both the topography of the area and overall size of the urban expanse, and also the high density of pollution sources within.”

It added: “Glasgow and its surrounding urban areas sit within the Clyde valley which is surrounded by hills. These hills cause a basin affect which in turn helps to prevent the dispersion of pollutants in specific weather events such as that seen on the 11 and 12 December.”

Glasgow city council

Glasgow city council operates seven air quality monitoring stations in the city: Glasgow Centre; Glasgow Battlefield; Glasgow Background; Glasgow Anderston; Glasgow Byres Road; Glasgow Kerbside; and Glasgow Chambers. More information on these sites and what pollutants are monitored at each is available on the Glasgow city council website.

On 1st March 2012, the council approved amendments to two of the three existing Air Quality Management Areas (AQMAs) and the creation of a further AQMA covering the whole of the city.

Glasgow now has AQMAs located at the City Centre, Byres Road / Dumbarton Road and Parkhead Cross for the pollutant nitrogen dioxide. The AQMA covering the whole of the city, meanwhile, has been declared for PM10 particulate matter.

The council’s ‘2012 Air Quality Updating and Screening Assessment’ found that in 2011 Glasgow Byres Road was the only site that continued to exceed the target levels for PM10 and that the Glasgow Kerbside site was exceeding the one-hour mean target for nitrogen dioxide.

In the assessment, published in June 2012, the council states its intention within a year to produce an updated Air Quality Action Plan following changes to the AQMAs and to produce a progress report on air quality for 2013.

The council’s previous Air Quality Action Plan from 2009 included actions to investigate the feasibility of introducing Low Emission Zones (LEZs), to introduce a strategy for reducing emissions from taxis and to clamp down on ‘idling’ vehicles in the city centre.

A spokesman for Glasgow city council said: “Air quality in Glasgow has improved dramatically in recent decades. However, like any other urban area with heavy traffic, there will be locations where there is a build up of emissions on some days, depending on other conditions. While local government has relatively limited powers to change the way society works and travels, we are taking a number of innovative steps that should have a positive impact on air quality over years to come.”

He continued: “For example, we have launched Scotland’s biggest Statutory Quality Partnership, which requires bus operators to invest in a modern, cleaner fleet; we back the City Car Club, which is one of the greenest anywhere in the world; we have introduced electric and low emission vehicles to our own services, and we will incentivise the use of electric vehicles by offering free parking on street and free charging in our car parks.”

Air pollution data for Scotland is monitored and regularly updated on the Scottish Air Quality website, which also features information on nitrogen oxides, sulphur dioxide, carbon monoxide and Ozone levels.