Johannesburg Convention

The alveolar dust is that fraction of the inhalable dust which reaches the alveoh. According to the Johannesburg Convention , all particles with an aerodynamic diameter below 7 pm are regarded as the alveolar fraction. Particles with much smaller diameters have a greater chance of being exhaled without deposition in the respiratory tract. 

Because of the differing human health effects caused by fine and coarse dust particles, these two types of particles have to be assessed separately. In the soparticle size fractions can be identified, which are further defined in the international standards ISO 7708 and EN 481 [6-103] ... 

Because of the relatively large amount of dust necessary for substance-specific analysis, stationary samplers capable of sampling large volumes of air have to be used to collect sufficient material for an accurate analysis. The already mentioned Gravikon VC 25, furnished with a fine-particle sampling head, is an example of a sampler for this task [6-109]. Like other fine dust samplers, this stationary device meets the requirements of the "Convention of Johannesburg (see Section 2.10). 

---