Authentication of particulate air samples by aerosol

A method was developed for the protection of aerosol filters against tamper ing that can be applied to any particulate sampler. In this method, tagged particles are dispersed into the sampled aerosol volume by liquid atomizati on to guarantee homogeneous distribution of the tag and deposition into the filter matrix. The tagged aerosols are collected insitu, together with the sampled dust particles. The tag can be measured in different ways, This fe ature can be used for self protection of the method. The authentication of the individual filters is preserved through the lifetime of the filter samp le. Long-term field tests of the equipment indicate reliable performance.