Airborne Droplets: Aerosols vs. Splatter?

Aerosols are defined as liquid or solid particles less than 50 micrometers in diameter.^20,21,32,33 Particles of this size are small enough to stay airborne for an extended period before they settle on environmental surfaces or enter the respiratory tract after inhalation.^20,21 Smaller particles of in aerosols (droplets and droplet nuclei 0.5 to 10 μm in diameter) have the potential to enter the lungs and settle within the bronchial passages, reaching as far as the pulmonary alveoli.^20,21 These droplets are thought to convey a high level of risk infection transmission in the dental office.^32,33

Splash and splatter a mixture of air, water, and/or solid substances larger than 50 μm in diameter are visible to the naked eye^20,21 and behave in a ballistic or projectile manner.²⁰ These mixtures are ejected forcibly from their origin in an arc and travel along a bullet-like trajectory until they contact a surface or fall to the ground under the influence of gravitational forces.²⁰ Unlike aerosols, splash and splatter are airborne only briefly.^20,21 Because of this, they demonstrate limited penetration into the respiratory system.^20,21

Within the dental office, airborne droplets and droplet nuclei present unique risks to DHCP and patients.^32,33 They can remain in the air for a long time, may be transported with air flows for long distances, and can contaminate wide areas within the dental operatory.^32-34 Splash and splatter, on the other hand, are generally deposited on surfaces closer to their origin, an estimated 15-120 cm from the source.^33,34 These particles are a risk due to their contact with mucous membrane and close surfaces, including DHCP.^33,34 Furthermore, there is evidence that some microorganisms may survive within splash and spatter and when the contaminated surfaces dry organisms may become airborne as dust particles.^33,34