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:
“He will place a tax on the air you breathe and on the bread you eat; he will give you a legislation which is as legitimate as it is unjust and instead of reasons, he’ll give you laws. These will grow in the course of time, until you no longer exist for yourselves but for others.”
—Franz Grillparzer (1791–1872)
“Talent alone can not make a writer. There must be a man behind the book; a personality which by birth and quality is pledged to the doctrines there set forth, and which exists to see and state things so, and not otherwise; holding things because they are things.”
—Ralph Waldo Emerson (1803–1882)