Particles containing cellulose are ubiquitous in the atmosphere and accounts for more than 5% by mass of the total organic matter even at elevated sites (Sánckez-Ocoa et al., 2007). In this work the ice nucleating activity of microcrystalline cellulose particles was measured by means of a dynamic filter processing chamber (DFPC). Results show low ice nucleation activity fraction (fIN) for particles below 0.4 μm and Ice Nucleation Active Surface-Site density (ns) higher for Fibrous Cellulose (FC C6288 Sigma) with respect to Microcrystalline powder (MCC, 435236 Sigma Aldrich).