In Air Quality
One measure of air pollution used in air quality standards is the atmospheric concentration of particulate matter. This measure is also sometimes referred to as the "particle number", although it is usually expressed in μg/m3 (micrograms per cubic metre).
Read more about this topic: Particle Number
Famous quotes containing the words air and/or quality:
“Spread outward. Crack the round dome. Break through.
Have liberty not as the air within a grave
Or down a well. Breathe freedom, oh, my native,
In the space of horizons that neither love nor hate.”
—Wallace Stevens (1879–1955)
“Emperor Joseph II: Your work is ingenious. It’s quality work, and there are simply too many notes, that’s all. Just cut a few and it will be perfect.
Mozart: Which few did you have in mind, majesty?”
—Peter Shaffer (b. 1926)