#airborne particles
- Aerobiology — An interdisciplinary branch of biology that deals with the study of living organisms and particles of biological origin (such as bacteria, fungi, pollen, spores, cysts, and viruses) passively transported through the air, as well as with the analysis of their movement, survival, and impact on the environment and human health.
- Aerosol — A heterogeneous macromolecular disperse system formed by a collection of fine particles, solid or liquid, stably suspended within a gaseous medium (such as atmospheric air). In a medical or industrial sense, the term designates either natural phenomena like fog and smoke, or pharmaceutical preparations sprayed under pressure for therapeutic inhalation directly into the airways.