Legal Regulations
In general, there are two types of air quality standards. The first class of standards (such as the U.S. National Ambient Air Quality Standards and E.U. Air Quality Directive) set maximum atmospheric concentrations for specific pollutants. Environmental agencies enact regulations which are intended to result in attainment of these target levels. The second class (such as the North American Air Quality Index) take the form of a scale with various thresholds, which is used to communicate to the public the relative risk of outdoor activity. The scale may or may not distinguish between different pollutants.
Read more about this topic: Air Pollution
Famous quotes containing the words legal and/or regulations:
“It has come to this, that the friends of liberty, the friends of the slave, have shuddered when they have understood that his fate was left to the legal tribunals of the country to be decided. Free men have no faith that justice will be awarded in such a case.”
—Henry David Thoreau (1817–1862)
“If it were possible to make an accurate calculation of the evils which police regulations occasion, and of those which they prevent, the number of the former would, in all cases, exceed that of the latter.”
—Karl Wilhelm Von Humboldt (1767–1835)