Designated concentrations of certain key
pollutants at which some degree of danger to public health is expected. In many areas in which
a relatively high level of pollution is often encountered, several levels of alert
are often established. For example, a first alert may signify a potential problem
exists; a second alert becomes a signal for the curtailment of certain significant
emission sources; the third alert signifies the need for some specified emergency
action which must be taken to ensure the public safety.
Source:
PAC, 1990, 62, 2167
(Glossary of atmospheric chemistry terms (Recommendations 1990))
on page 2173
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
