Particulate mixes are commonly present in environment. Environmental scientific and eco-/cito-toxicology studies facing nowadays problems of particle characteristics to improve radiative transfer models and short/long-term particle impact on ecosystems. Particulate is classified in three modes namely ultrafine (nucleation and Aitken mode, diameter less than 0.1 μm), fine (mainly accumulation mode, aerodynamic diameter between 0 and 2.5μm) and coarse (aerodynamic diameter between 2.5 and 10μm). Generally, fine and ultrafine particles are formed from high temperature processes such as vehicular exhaust, oil and coal combustion, biomass burning, industrial processes, and chemical reactions in the atmosphere. Coarse particles are generally evolved from attrition processes including mechanical abrasion of crustal material and re-suspension of road and soil dusts, sea spray, volcanic eruptions and brake and tyre wear from vehicles. Morever almost all the products may release particles in environments and adequate characterisation of their impact is mandatory to define particle-particle and particle-medium interaction with complex matrix which can change particle characteristics, as well as their long-term behaviour. The capabilities of Classizer™ ONE and SPES patented method provide unique added value time resolved classification of particles suspended in environmental fluids. Thanks to its unique properties, SPES was able to investigate, in a deeper way with respect to traditional light scattering technologies, the sample composition as well as other peculiar behaviors in sample aging and degradation, even in target environmental waters.

The case of Lipid/ZnO Emulsion in Environmental Waters
Characterization of envorinmental behaviour of particle with heterogeneous complex structure is an essential task in the product formulation. As a reference Zinc Oxide (ZnO) is very widely used as an additive in a variety of industrial application which may release particles in or directly target environmental waters including plastics, ceramics, cement, lubricants, paints, adhesives, pigments, and foods. In the example ZnO is encapsulated in an oil/lipid phase (ZnO-LP) and dispersed in aqueous phase. Empty lipid particles (LP) are studied as control. Each sample is suspended and incubated in water with different characteristics (ultrapure water, reservoir water, sea water, peatbog water). Analyses are processed at determined timepoints monitoring the behaviour and stability of particles. Thanks to its unique properties, Classizer™ ONE provides sample information on peculiar behaviours in particle aging and degradation, even in environmental complex medium. Please refer to Application Note AN012 Monitoring the Fate of a Lipid/ZnO Emulsion in Environmental Waters for further information.

Application_Environmental_LP-ZnO in waters

(in figure) Evolution of LP and lipidic ZnO particles in sea water at three time steps: day 0, day 10, day 20. Red line corresponds to the expected Mie curve for n = 1.43, reported here as a guide to the eye.

The case of dust in glacial waters
Dust influences global climate both directly, by changing the radiative properties of the atmosphere through scattering and absorption of solar (shortwave) and terrestrial (longwave) radiation, and indirectly, impacting on cloud formation and properties. While most modelling studies assume a spherical shape for dust particles, detailed analyses of modern desert dust reveal significant deviations of light scattering from scattering properties of homogeneous spheres. Accordingly, adequate modelling of light scattering by non-spherical particles is necessary but represents one of the major difficulties in remote sensing of modern aerosols and dust. Classizer™ ONE measures directly the dust optical thickness (ρ) and the extinction cross section (Cext) for each measured particle. Thus, Classizer™ ONE derives information on dust particle shapes (and aspect ratio in particular), which is a critical piece of information needed to properly derive the intrinsic optical properties used by radiative transfer models.