Suspended particles

See also: PM

The suspended particles (noted PM in English for Particule Matter ) are generally the fine particles, carried by the Eau or the Air and that one can collect and quantify by Filtration or by other physical processes.

In the case of the Atmospheric pollution, weak the average Masse of the suspended particles in the air gives them a falling speed by negligible Gravité. Schematically according to the form of the particles and their density, one can even in the case of retain that for traditional particles, their diameter would be appreciably lower than 50 Micromètre S, very light particles with 100 micrometers. Above these values, the particles are not any more maintained in suspension by the resistance of the air and fall according to their Densité; they then are qualified sedimentable Poussières, noted P.Sèd .

The Métrologie of PM makes call in the case of the Surveillance of the quality of the air with very sophisticated physical methods; the metrological reference being the Gravimetry, but which with the disadvantage of being a discontinuous method; to determine PM uninterrupted, one uses either of the microphone-balances to quartz, or of the beta ray probes, or sensors with laser Diffraction.

According to the size of the particles (aerodynamic Diameter or aerolic Diameter), one distinguishes in metrology PM 10 , PM 2,5 or PM 1 according to the size of the particles in Micromètre (10-6 m).

  • PM 10 suspended particles in the air, of an aerodynamic diameter (or aerolic diameter) lower than 10 micrometers. The finer particles can be referred:

  • PM 2,5 whose diameter is lower than 2,5 micrometers, called fine particles
  • PM 1 whose diameter is lower than 1 micrometer, called ultrafine particles

  • Stakes on the level of health
According to their sizes, these fine particles have a different penetration in the respiratory system. Particles of the P2,5 type for example arrive up to the level of the air cells.

  • Control and monitoring

These measurements are ensured in France by the Associations Approved of the Monitoring of the Quality of the Air (AASQA).

See too

External bond

  • Suspended particles and health summarized of GreenFacts of scientific reports/ratios of WHO
  • site of the government of the Walloon region (Belgium)

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