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  • The iSPEX project is an experiment. Results are not guaranteed.
  • The goal of the iSPEX project is to measure the density of  fine dust, its particle size distribution, and a rough indication of the composition of fine dust based on the determination of the complex refractive index. The latter quantities are important for health studies on fine dust .
  • The results of iSPEX measurements do not provide quantities for which official or legal standards are applicable.
  • Results of iSPEX measurements cannot be directly compared with PM10 or PM2,5 measurements; they are of a different nature. A direct comparison with limit values for fine dust (in ug/m3) is  therefore not possible. See  lml.rivm.nl for PM10 or PM2,5 values.
  • With iSPEX you measure not only the fine dust in the close vicinity near the ground, but also further away, in the higher parts of the atmosphere. Whether  iSPEX measurements are relevant for the air you breath can only be determined with the help of additional measurements and/or model calculations.
  • iSPEX only works properly for a cloudless blue sky.
  • An individual iSPEX measurement gives-directly when using the App- only a qualitative  indication of the sky brightness at a low accuracy.
  • The indication of the presence of fine dust given in the App is related to the optical thickness of the dust. This is complex information and a proper interpretation requires specialist knowledge.
  • Individual iSPEX measurements have to be averaged over approximately 100 measurements to obtain reliable values.
  • Initially the iSPEX project will focus only on the analysis of the data obtained during the Dutch national iSPEX measurement day.
  • The analyses of the iSPEX data and the determinations of the quantities mentioned above are done centrally by the iSPEX team and will only be made available through or with explicit permission of the RIVM and the KNMI.
  • The data obtained during the iSPEX project will be used for scientific research. Scientific results will be anonimized before analysis and publication.