Means literally, "dissolved in air".
Aerosol describes any suspension of solid particles or liquids in a gas (like air),
such as smoke, haze or air pollutants
Aerosols, small particles suspended in air with a lifetime of at least minutes,
are either emitted as primary aerosols (dust or particle emissions ofdiesel cars)
or formed by the conversion of sulfur dioxide, nitrogen oxides, ammonia and organic compounds
in atmospheric chemical reactions to sulfates, nitrates and ammonium compounds,
and non-volatile organics (secondary aerosol).
The total mass of aerosols per unit of volume is referred to as "Particulate Matter" or TSP (Total Suspended Particulates).
The smller aerosols are, the deeper they can get into the human respiratory tract;
since many of them are hazardous to human health, this is a problem that is increasingle
recognized as a major component of, in particular, urban air pollution.
- PM-10 describes aerosol particles with a diameter of 10 μm or smaller.
- PM-2.5 describes aerosol particles with a diameter of 2.5 μm or smaller
- PM-1 describes aerosol particles with a diameter of 1.0 μm or smaller.