%0 Journal Article %T Experimental Study on the Dependency of Ice Nucleation Active Surface Site Density on ATD Aerosol Size %A Franco Belosi %A Gianni Santachiara %J Atmospheric and Climate Sciences %P 426-440 %@ 2160-0422 %D 2021 %I Scientific Research Publishing %R 10.4236/acs.2021.113025 %X In light of the percentage of Earth¡¯s cloud coverage, heterogeneous ice nucleation in clouds is the most important global-scale pathway. More recent parameterizations of ice nucleation processes in the atmosphere are based on the concept of ice nucleation active surface site density (ns). It is usually assumed that ns is independent of time and aerosol size distribution, i.e. that the surface properties of aerosols of the same species do not vary with size. However, the independence of ns on aerosol size for every species has been questioned. This study presents the results of ice nucleation processes of ATD laboratory-generated aerosol (particle diameters of 0 - 3 ¦̀m). Ice nucleation in the condensation mode was performed in a Dynamic Filter Processing Cham- ber at temperatures of -18°C and -22°C, with a saturation ratio with respect to water of 1.02. Results show that ns increased by lowering the nucleation temperature, and was also dependent on the particle size. The ns %K Ice Activated Fraction %K Ice Nucleation Active Surface Site Density %K Condensation Freezing %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=109559