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 ... trippingly on the tongue; but if you mouth it ... I had as lief the town crier had 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)
“A person must have a good memory to keep the promises he has made. A person must have a strong imagination to be able to have pity. So closely is morality tied to the quality of the intellect.”
—Friedrich Nietzsche (1844–1900)