2. Sampling

Correctly collecting an aerosol is always a difficult operation, and certainly much more difficult than collecting a gas. You need to obtain a representative sample, avoid artifacts during sampling and know, if possible, the size of the particles collected. During sampling, particle fractionation may occur (some particles are not collected), if the sampling system is unsuitable. It is therefore essential to eliminate the presence of bends in pipes. Losses can also occur as a result of electrostatic charges deposited on the filter or filter clogging, if sampling is too long, etc.

Overall sampling efficiency is linked to :

• device geometry ;

• wind speed ;

• at filter load ;

• to the flow rate of the pump used.

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