Environmentalists are demanding urgent investigations into air pollution on the Glasgow subway after a snapshot survey by the Sunday Herald’s New Era magazine discovered that passengers were breathing in tens of millions of tiny metallic particles that might damage their health.
We found levels of pollution by microscopic particles on the subway - known in the city as the Clockwork Orange - up to ten times higher than on the streets outside and up to eight times above the World Health Organisation’s recommended daily limit.
Experts estimate that passengers on the subway for 45 minutes could each inhale at least 60 million particles. Anyone spending the same amount of time at one of Scotland’s busy railway stations could breath in 10 million particles, or 2.5 million on a train journey between Glasgow and Edinburgh.
Because the particles in the electric-powered subway are likely to be mostly iron oxide from the grinding of wheels against rails, they may not be as dangerous as the sooty particles emitted by trains or cars driven by diesel engines. But experts and campaigners all agreed that the risks required serious examination.
Dr Richard Dixon, the director of Friends of the Earth Scotland described the concentrations of particle pollution on the subway as “alarming”. He called on Strathclyde Partnership for Transport (SPT), which runs the subway, to take the results very seriously.
“This problem urgently needs further investigation," he said. "Confirmation of these results would require decisive action to reduce pollution.”
Alison Johnstone MSP, environment spokeswoman for the Scottish Greens, urged SPT to respond urgently to New Era’s findings. “They should ensure that Glaswegians don't find they escape polluted air on the streets only to suffer even more severe problems underground,” she said.
Air pollution was measured on a 40-minute subway journey on the afternoon of Friday 10 May. A portable, state-of-the art monitor detected concentrations of between 40 million and 80 million particles per cubic metre of air.
In Glasgow Central Station levels peaked at just over 40 million, and at Edinburgh Waverley Station they just topped 10 million. In Glasgow city centre they once went over 10 million, but were otherwise lower.
The air pollution expert who helped with the monitoring, Dr Sean Semple from the University of Aberdeen, agreed that the high levels in the subway required investigation. Concentrations of tiny particles can be much higher in cars, trains, buses, railway stations and other enclosed spaces than outdoors, he pointed out.
“These tend to be the places where we spend most of our time and yet they are the environments that we know least about in terms of air quality,” he said.
New Era’s survey showed how exposure to particles could vary markedly in the space of a few metres, he added. “There are peaks from diesel engines during taxi journeys, on station platforms and in trains - and high levels of particles during transport on the Glasgow subway system.”
Air pollution has been linked to asthma, heart attacks and strokes, and blamed by government experts for causing 29,000 early deaths every year in the UK. According to Semple, lungs were better able to cope with the iron particles from the subway than diesel particles, but the health effects needed more study.
The fine diesel particles detected at mainline railway stations and on some older trains had been shown to be hazardous, he said. “We know that these very small particles are harmful to health and exposures to high levels can be particularly problematic for people with heart or respiratory conditions.”
SPT, however, described the Sunday Herald survey as “sensational” and “alarmist”. It complained that it had not been shown the full scientific evidence, or details of how the survey was conducted.
“There are a huge array of factors during even the shortest journey which can impact on pollution monitors and it is not clear from this snapshot if that has been taken into consideration,” said an SPT spokeswoman. “However, SPT takes both passenger and staff health very seriously and uses respected industry expertise to guide us on best practice in the subway.”
Network Rail, which owns Waverley and Central stations, said it was committed to cutting pollution “where possible”. It limited train idling time, and restricted vehicle access to stations.
“Further planned electrification of the network will also reduce the number of diesel trains using our busiest stations,” said a company spokesman. “We would also be happy to review the data collected.”
This weekend, New Era also publishes the first ever maps revealing the most polluted streets in Glasgow, Edinburgh and Perth. Large parts of the city centres are shown to be polluted in breach of safety limits, and a risk for those with lung or heart conditions.
Local authorities have identified 13 urban areas across Scotland where air pollution is a problem. As well as Glasgow, Edinburgh, Dundee, Aberdeen and Perth, these include Bearsden, Paisley, Falkirk, Broxburn and Dunfermline.
The detailed results of the monitoring are available at the end of a related story here.