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8.10.2008 A portable measurement unit to monitor the air we breathe
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| Jyrki
Mäkelä, lecturer at Tampere University of Technology (Left)
and Jarmo Lilja, lecturer at TAMK University of Applied Sciences
scrutinising the results of measurements of fine particles from the
outside air in the city of Tampere. High resolution image (340 Kb) Photo: Kalle Heiska |
As
we breathe coarse particles (diameter 2.5 to 10 micrometers) and larger
fine particles (all under 2.5 micrometers) immediately irritate the
respiratory tract, stick in people’s bronchi and exit the body a
few hours later when they sneeze or expel mucous. Typical examples are
dust from streets and roads and, for example, airborne salt particles
resulting from waves crashing against the coast.
Smaller fine and extra fine particles penetrate deep into the body
through the saccules in the lungs and enter the veins and heart. Their
contribution to sickness has only recently been researched; for
example, in the USA an association has been demonstrated between
hospital visits due to heart and circulatory symptoms and the
microparticle counts in the area. Changes in the coarse particle count
were not associated with the occurrence of such symptoms.
The EU has set a target value for outdoor air in 2010 regarding the
maximum total mass of particles under 2.5 micrometers at an average of
25 microgrammes per cubic metre per 24 hours. In 2015 that target value
will become a limit for official action.
The measuring device in the TAMK mobile instrument was used on
instructions from the city administration to investigate the quality of
air in the Kaleva area of the city. These findings are currently being
compared with those of a fixed measuring station in another part of the
city. The aim is to compare the findings of measurements of fine
particles against the statistics of local hospitals and health centres
on respiratory and heart symptoms. It is estimated that in Finland
there are some 200 – 1,300 premature deaths due to extra fine and
the very finest particles in the air.
ELPI, or Electrical Low Pressure Impactor, the TAMK portable unit is
capable of measuring particles with diameters from 7 nanometers to 10
micrometers. The device in the portable unit separates the mass
accumulation of the different sized particles and the number of
particles. International health and physics researchers are
increasingly interested in finding out more about a possible
association between particles under 0.5 micrometers in diameter and
cardiovascular diseases. Among the most recent research objects is a
possible dependency of increasing importance on the total surface area
of these particles. This is one of the interesting quantities the
measuring instrument developed by Dekati is already able to measure.
The portable measuring instrument is part of the TAMK research and
development work and six theses were accomplished in the course of its
construction. The vehicle also includes devices for measuring oxidants,
air temperature and humidity and wind characteristics. Towed behind a
private car, it can easily be taken wherever it is needed.
More information:
| TAMK University of Applied Sciences Lecturer, Dr. Tech. Jarmo Lilja Tel. +358 50 554 2440 firstname.surname@tamk.fi |
City of Tampere Environmental inspector Milla Hilli-Lukkarinen Tel. +358 3 5656 6656 firstname.surname@tampere.fi |
| Tampere University of Technology Lecturer, Docent Jyrki M. Mäkelä Tel. +358 40 733 5405 firstname.surname@tut.fi |
