New measurements show high air pollution in the Copenhagen metro
Graphical summary. Credit score: Setting Worldwide (2022). DOI: 10.1016/j.envint.2022.107621

Yearly, air air pollution is answerable for 4,200 Danes dying prematurely and is linked by the WHO to diabetes, most cancers and coronary heart illness. In Copenhagen, air air pollution is measured by numerous measuring stations on rooftops across the metropolis.

However the air underground, which is breathed by the 80 million individuals who use the metro every year, has been a blind spot in measuring the town’s air high quality. Now, researchers from the Division of Chemistry on the College of Copenhagen, in collaboration with Aarhus College, have for the primary time measured the air air pollution underground within the Copenhagen subway system.

The measurements present that the air is polluted with ultra-small particles dangerous to well being at a degree that’s 10 to twenty occasions larger than measurements taken proper subsequent to the City Corridor Sq. on the closely trafficked H.C. Andersens Boulevard. A stretch which till now has been assessed because the capital’s most polluted.

“Our measurements present that the metro might be the place in Copenhagen’s public area the place you’re uncovered to probably the most concentrated air air pollution. In the event you use the subway rather a lot or work there, it will probably have an effect in your well being and may very well be the most important single merchandise contributing to your annual publicity. Measures must be taken to cut back the focus of particles fairly a bit,” says Professor Matthew S. Johnson from the Division of Chemistry, who led the research.

The air air pollution within the subway comes primarily from the trains’ brakes, wheels and rails, that are product of iron. The friction from the trains working and decelerating releases iron particles into the air, which make up 88 % of the particles that the researchers had been in a position to determine of their analyses.

New measurements show high air pollution in the Copenhagen metro
The particles within the filter had been collected in 19 hours over three days at Nørrebros Runddel metro station. Credit score: Hugo S. Russel.

The iron particles are so small that they’ll simply penetrate lung tissue and straight into the blood. Subsequently, in keeping with the WHO, they’re, on par with different small particles, dangerous to human well being.

The particles within the filter was collected in 19 hours over three days at Nørrebros Runddel metro station. Picture: Hugo S. Russel.

Metropolis ring and Discussion board are the worst

The researchers have made measurements from trains on all traces and from 14 metro stations. It’s worst contained in the trains themselves on Cityringen, M3, the place the focus of particles is on common 20 occasions larger than at H.C. Andersens Boulevard near Rådhuspladsen and twice as excessive as within the trains on metro traces M1 and M2.

It is because the Metropolis ring consists of 17 underground stations and subsequently will get little or no air flow down into the tunnel in comparison with the M1 and M2, which run above floor for a few of the part.

“It’s known as the ‘piston impact,’ the place the trains push the polluted air out of the tunnel once they journey above floor. M1 and M2 profit from that impact, though the air remains to be more and more polluted the additional away you get from the above-ground stations. However as a result of the Metropolis Ring solely runs underground, you do not get the pure change within the air there, solely a smaller quantity of air pushed by means of the air flow shafts, and subsequently it’s way more polluted,” explains Ph.D. Hugo S. Russell from Aarhus College, who has been answerable for gathering and analyzing the samples along with Niklas Kappelt.

Discussion board Station take the prize as probably the most polluted stations throughout all the metro community. It has a a lot larger focus of particles in comparison with e.g. Nørreport, Kongens Nytorv, Christianshavn and Amagerbro.

Details concerning the measurements:

  • Within the scientific article printed within the journal Setting Worldwide, the researchers conclude that “the system is surprisingly polluted regardless of its latest building” in 2019.
  • Contained in the trains on the Cityringen M3, researchers have measured that there’s a mean of 20 occasions the focus of particles within the air as close to H. C. Andersens Boulevard, which is alleged to be one of the polluted locations in Copenhagen.
  • The Nørrebros Runddel and Discussion board stations are probably the most polluted throughout all the metro community.
  • The particles primarily encompass 88% iron, which originates from practice rails, wheels and brakes.
  • The measurements had been revamped 16 days in March and April 2021 and had been carried out within the trains whereas they had been working and on the stations.
  • A measuring instrument known as a TSI DustTrak DRX Aerosol Monitor 8533 was used, in addition to small optical particle sensors and gravimetric samplers.
  • The composition of the gravimetric samples was analyzed with particle-induced X-ray emission (PIXE) evaluation.
  • Common ranges of 109 micrograms per cubic meters was measured at underground stations on the M1 and M2 traces, that is 10 occasions the road degree recorded in central Copenhagen on the time of measurement (11 µg m−3 ).
  • For the M3 line, the typical concentrations on the trains had been 219 micrograms of particles per cubic meter, which is 20 occasions larger than avenue degree in central Copenhagen and better than on the platforms (168 micrograms per cubic meter), which isn’t typical in comparison with different metro techniques.
  • In outside air, the EU has a purpose that the focus of ultrafine particles over a yr should stay beneath a mean of 25 micrograms per cubic meter.
  • The World Well being Group (WHO) recommends that the typical publicity over a yr is a most of 5 micrograms per cubic meter, as a result of it’s estimated that greater than that may doubtlessly be dangerous to well being.

Air flow can cut back air pollution

In line with the researchers, issues with excessive air air pollution in metro techniques should not a brand new phenomenon. In i.a. Related issues have been recognized in London, Paris, Stockholm, Barcelona, Seoul and Toronto, and the answer right here has primarily been extra air flow of the air. The researchers estimate that this will even be capable of considerably cut back the focus of particles within the Copenhagen metro.

“In Barcelona, they merely turned on the air flow shafts that had already been put in, however had been meant for warmth management, and that introduced the particle focus down. The Copenhagen subway additionally has a similartype of air flow shaft meant for fires, however they aren’t in use right now. You might contemplate turning them on,” says Professor Matthew S. Johnson and provides:

“In any other case you find yourself having to vary wheels, rails and brakes to different supplies. A really costly affair besides, one thing that they selected to do within the Toronto and Montreal metros,” says Matthew S. Johnson.

One other potential perpetrator for the air pollution contained in the trains is the glass doorways that separate the platform from the practice. They assist to insulate the particles within the tunnels and cut back the air flow there. An issue that has additionally been noticed in South Korea.

“Research from Seoul’s subway system have proven that doorways between the platform and the practice monitor enhance the air high quality within the stations, however make it worse contained in the trains. There may be in fact a security concern, however it’s price contemplating,” says Hugo S. Russell.

Extra info:
Niklas Kappelt et al, Particulate air air pollution within the Copenhagen metro half 1: Mass concentrations and air flow, Setting Worldwide (2022). DOI: 10.1016/j.envint.2022.107621

Hugo S. Russell et al, Particulate air air pollution within the Copenhagen metro half 2: Low-cost sensors and micro-environment classification, Setting Worldwide (2022). DOI: 10.1016/j.envint.2022.107645

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New measurements present excessive air air pollution within the Copenhagen metro (2023, January 20)
retrieved 20 January 2023
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