TITLE:
Ammonia Diffusion Phenomena through NalophanTM Bags Used for Olfactometric Analyses
AUTHORS:
Selena Sironi, Lidia Eusebio, Laura Capelli, Emanuela Boiardi, Renato Del Rosso, Jean-Michel Guillot
KEYWORDS:
Sampling Bag, Diffusion, Odour Sampling, Ammonia, Nalophan
JOURNAL NAME:
Journal of Environmental Protection,
Vol.5 No.11,
August
22,
2014
ABSTRACT: The
ammonia loss through NalophanTM bags has been studied. Ammonia was
chosen as target compound in order to be representative of odorous molecules of
small dimensions. The losses observed for storage conditions and times as
allowed by the reference standard for dynamic olfactometry (EN 13725:2003)
indicate that odour concentration values due to the presence of small molecules
may be significantly underestimated if samples are not analysed immediately
after sampling. The diffusion coefficient of ammonia through the NalophanTM film was evaluated using the Fick’s law, and it turned out to be equal to 2.38E-12 (m2/s). The results and their theoretical
interpretation indicate that concentration losses due to ammonia diffusion
through the NalophanTM film can be decreased by using large bags and
filling them up to their maximum capacity.