Aerosol

An aerosol is a <a href="/facts/Suspension_(chemistry)/S3xp96TL">suspension</a> of fine <a href="/facts/Solid/YU0hJq6f">solid</a> <a href="/facts/Particle/JHKr2w6h">particles</a> or <a href="/facts/Liquid/t9GkLWzt">liquid</a> <a href="/facts/Drop_(liquid)/m4kuGAgH">droplets</a> in <a href="/facts/Air/6IyFHIpG">air</a> or another <a href="/facts/Gas/hVVAoodV">gas</a>. Aerosols can be generated from natural or <a href="/facts/Human_impact_on_the_environment/vIAWqfPB">human causes</a>. The term aerosol commonly refers to the mixture of <a href="/facts/Particulates/RleGr5E6">particulates</a> in air, and not to the particulate matter alone. Examples of natural aerosols are <a href="/facts/Fog/mrIdyIc7">fog</a>, <a href="/facts/Mist/E7NwCppk">mist</a> or <a href="/facts/Dust/vaNKP8wk">dust</a>. Examples of human caused aerosols include <a href="/facts/Particulate/RleGr5E6">particulate</a> <a href="/facts/Air_pollutants/zmk9Dy7S">air pollutants</a>, mist from the discharge at <a href="/facts/Hydroelectric_dam/zEeJIK2B">hydroelectric dams</a>, irrigation mist, perfume from <a href="/facts/Spray_nozzle/xlvwoAoM">atomizers</a>, <a href="/facts/Smoke/KRJaumoC">smoke</a>, <a href="/facts/Dust/vaNKP8wk">dust</a>, <a href="/facts/Pesticide/Uhf4KnwJ">sprayed pesticides</a>, and medical treatments for respiratory illnesses.
Several types of atmospheric aerosol have a significant effect on Earth's climate: volcanic, desert dust, sea-salt, that originating from biogenic sources and human-made. Volcanic aerosol forms in the stratosphere after an eruption as droplets of <a href="/facts/Sulfuric_acid/Wom6fymJ">sulfuric acid</a> that can prevail for up to two years, and reflect sunlight, lowering temperature. Desert dust, mineral particles blown to high altitudes, absorb heat and may be responsible for inhibiting storm cloud formation. Human-made <a href="/facts/Sulfate_aerosol/rzGmC0Dx">sulfate aerosols</a>, primarily from burning oil and coal, affect the behavior of clouds. When aerosols absorb pollutants, it facilitates the deposition of pollutants to the surface of the earth as well as to bodies of water. This has the potential to be damaging to both the environment and human health.
<a href="/facts/Ship_tracks/UVK9WIdX">Ship tracks</a> are <a href="/facts/Cloud/KDgo0Wqu">clouds</a> that form around the <a href="/facts/Exhaust_gas/kLpq1eUX">exhaust</a> released by ships into the still ocean air. Water <a href="/facts/Molecule/N9ljSfFq">molecules</a> collect around the tiny particles (<a href="/facts/Particulate/RleGr5E6">aerosols</a>) from exhaust to form a <a href="/facts/Cloud_seed/8u5mVsFR">cloud seed</a>. More and more water accumulates on the seed until a visible cloud is formed. In the case of ship tracks, the cloud seeds are stretched over a long narrow path where the wind has blown the ship's exhaust, so the resulting clouds resemble long strings over the ocean.
The warming caused by human-produced greenhouse gases has been somewhat offset by the cooling effect of human-produced aerosols. In 2020, regulations on fuel significantly cut sulfur dioxide emissions from international shipping by approximately 80%, leading to an unexpected global geoengineering termination shock.
The liquid or solid particles in an aerosol have diameters typically less than <a href="/facts/Micrometre/7eDFxD2L">1 μm</a>. Larger particles with a significant settling speed make the mixture a <a href="/facts/Suspension_(chemistry)/S3xp96TL">suspension</a>, but the distinction is not clear. In everyday language, aerosol often refers to a <a href="/facts/Aerosol_spray/8SfNdfYs">dispensing system</a> that delivers a consumer product from a <a href="/facts/Spray_can/8SfNdfYs">spray can</a>.
<a href="/facts/Airborne_disease/hpm1oR83">Diseases can spread</a> by means of small droplets in the <a href="/facts/Breath/92Wov2gk">breath</a>, sometimes called <a href="/facts/Bioaerosols/jQ1mjHsA">bioaerosols</a>.

Aerosol open-in-new

Aerosol