The highest concentration of a given trace component which was measured with a continuous analyser
during a specified sampling period.
PAC, 1990, 62, 2167
(Glossary of atmospheric chemistry terms (Recommendations 1990))
on page 2205
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. doi:10.1351/goldbook