Aerosol

Subject: Environment

Context:

WHO has formally acknowledged the possibility that the novel coronavirus can remain in the air in crowded indoor spaces, where short-range aerosol transmission cannot be ruled out.

Concept:

• Aerosols are defined as a combination of liquid or solid particles suspended in a gaseous or liquid environment.
• “Primary” aerosols, like dust, soot, or sea salt, come directly from the planet’s surface. They get lifted into the atmosphere by gusty winds, shot high into the air by exploding volcanoes, or they waft away from smokestacks or flames.
• “Secondary” aerosols form when different things floating in the atmosphere like organic compounds released by plants, liquid acid droplets, or other materials—crash together, culminating in a chemical or physical reaction.
• Aerosols come from both natural and human sources.
• Natural sources of aerosols include sea salt generated from breaking waves, mineral dust blown from the surface by wind, and volcanoes.
• Anthropogenic aerosols include sulfate, nitrate, and carbonaceous aerosols, and are mainly from fossil fuel combustion sources.