aerosolssuspensions

An aerosol suspension is a system in which fine solid or liquid particles are dispersed in a gas, usually air. The dispersed phase may consist of solid particles (dust, pollen, soot, smoke) or liquid droplets (fog, mist, spray). An aerosol can be natural, like sea spray or volcanic ash, or engineered for specific uses, such as pharmaceutical inhalants or consumer aerosols.

Formation methods include atomization, spray drying, nebulization, combustion, or condensation of vapors. Stability of the suspension depends on particle size distribution, density, hygroscopicity, and ambient conditions. Particles settle under gravity but are also transported by air flow. In air, tiny particles undergo Brownian diffusion and, if charged, electrophoretic forces can alter aggregation. Coagulation, evaporation or condensation shift the size distribution, and humidity can cause hygroscopic growth or dissolution.

Characterization uses instruments such as scanning mobility particle sizers, optical particle counters, aerodynamic particle sizers, and samplers with filters or impactors. Size is often expressed as aerodynamic diameter or mobility diameter. Common ranges: ultrafine below 100 nm, fine 100 nm to 2.5 µm, coarse 2.5–10 µm.

Usage spans inhalation therapies (metered-dose inhalers, nebulizers) and consumer products (sprays, fragrances). In atmospheric science, aerosols influence climate and air quality. Health aspects concern inhalation exposure linked to respiratory and cardiovascular effects; control measures include ventilation, filtration, and proper product labeling.