Poor air quality caused by cold weather, street dust, and exhaust fumes troubles Helsinki residents

Particle content on Mannerheimintie has already exceeded acceptable limit 12 times this year

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On Wednesday morning, quite a few pedestrians were seen to breathe through their woollen gloves in central Helsinki. The weather, though sunny and beautiful, was cold, dry, and bronchially treacherous.
      Measurements confirmed what everyone could smell. The pollution content of the air in the centre of the city and also elsewhere in the metropolitan area was exceptionally high.
      Street dust can cause irritation symptoms such as blocked nose, coughing, and stinging of the airways. It can be hazardous to sensitive people's health.
      "Usually the spring dust season starts at the end of April, but this year the exceptionally cold weather has advanced its arrival", says air protection expert Maria Myllynen from the Helsinki Metropolitan Area Council (YTV).
     
On Mannerheimintie, the main north-south thoroughfare of Helsinki, the measured street dust levels have already exceeded on 12 occasions the allowed upper particle limit set by the European Union.
      The dust mainly originates from the sand that is spread on icy streets in wintertime and from the constant wearing of the asphalt.
      Already on March 1st, record readings were measured on Mannerheimintie. In a cubic metre of air, 184 micrograms of particles were measured, against the allowed 50 micrograms per a 24-hour period.
      In the course of the winter, high readings have been registered in other locations as well, such as on Hämeentie, and in Espoo's Leppävaara suburb.
     
The European Union requires an explanation if the permitted particle content is exceeded more than 35 times in a year.
      This is likely to happen at several different locations this spring.
      Another factor that further weakened the air quality on Wednesday morning was the exhaust fumes. On many of the busy streets in downtown Helsinki, the air quality dropped from fair to poor, or even extremely poor.
     
A weather inversion caused by cold nights combined with negligible winds has made the situation even more difficult. The pollution content of standing air does not decline. In addition to street dust, high nitrogen dioxide levels have also been measured.
      Inversions happen on cold, calm nights, when the air layer close to the ground cools down and gets colder than the air above.
      The colder air remains on the street level, sealing in the pollution. Without wind to assist them, the air masses will not get stirred up and the pollution concentration remains high.
     
Because of the cold weather, the morning frost has lingered well into the forenoon, keeping the morning rush-hour pollution down on the street level.
      Yesterday, the temperature remained well below freezing until 11.30, after which the air masses finally started to mix.
      On Helsinki's busiest streets, salt has been used to bind the dust. Water can only be used to wash off the sand once the temperature rises permanently above freezing.
     
The beginning of March has been exceptionally cold in Southern Finland. According to the Finnish Meteorological Institute, this has been the coldest start to the spring in Southern Finland since 1987. The beginning of March is among the coldest recorded between 1961-2005.
      The mean temperature of the first half of the month was measured at -10.3 degrees Celsius at Helsinki-Vantaa International Airport, and -9.4 and -13.3 in Turku and Jyväskylä respectively.


Links:
  Helsinki Metropolitan Area Council: Air quality now
  Finnish Meteorological Institute

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