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:
“Speak the speech, I pray you, as I pronounced it to you—trippingly on the tongue; but if you mouth it, as many of your players do, I had as lief the town-crier spoke my lines. Nor do not saw the air too much with your hand, thus, but use all gently; for in the very torrent, tempest, and as I may say, the whirlwind of your passion, you must acquire and beget a temperance that may give it smoothness.”
—William Shakespeare (1564–1616)
“The past is interesting not only for the beauty which the artists for whom it was the present were able to extract from it, but also as past, for its historical value. The same goes for the present. The pleasure which we derive from the representation of the present is due not only to the beauty in which it may be clothed, but also from its essential quality of being present.”
—Charles Baudelaire (1821–1867)