Les nanoparticules dans l'air, génération, détection et granulométrie

摘要

Nanometric aerosol particles are present in the atmosphere with high concentrations. First detected at the end of the last century, they are formed essencially from gas-particle conversions. Similarly, high concentrations of nanoparticles may be found in marine aerosols during low tide. In addition, naturally occuring radioactive aerosols (such as radon derivatives) commonly possess both nanometric and subnanometric dimensions. Meanwhile, this nanometric aerosol may be found in number of process, such as in : electric ovens, combustion process, chemical reactors for synthetic materials, electrostatic discharges, nanostruc-tures, ceramics and sintering new nanostructured materials etc. They are also becoming increasingly common in a number of process and industries, which we will term « nano-industries ». Other than their dimensions, nanoparticles possess a number of physical properties that are completely different to there larger relatives. Such differences are highlighted in particle measurement methods. In this article, we will attempt to review current methods of particle generation, detection and measurement analysis of this type of aerosol. We will review nanometric polydispers generators that use spraying and evaporation-condensation methods. In addition, monodisperse aerosol generation using electrostatic classification methods with the Differential Mobility Analyser (DMA) and the Spectrometre de Mobilite Electrique Circulaire (SMEC) will be discussed. The ultrafine condensation nucleus counter (UCNC) will provide a platform for the discussion of particle detection methods and sizing when combined with the DMA or diffusion battery. Finally, we will discuss another device capable of determining the diameter of both sub-nanometer and nanometer-sized aerosol particles : the supersonic impactor.%L'aérosol nanométrique est présent dans l'air atmosphérique en concentrations élevées. Il résulte essentiellement de la conversion gaz-particules. L'aérosol radioactif naturel (descendants du radon) sous forme libre est lui aussi de dimensions nanométriques et même subnanométriques. On rencontre également l'aérosol nanométrique dans un certain nombre d'industries telles : fours électriques, combustion, réacteurs chimiques pour matériaux synthétiques, décharges électrostatiques, nanostructures, céramiques et frittes, nouveaux matériaux à nanostructures etc. Dans cet article, nous passons en revue les méthodes de génération, de détection et de mesure de la granulométrie de cet aérosol.