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ambient air standard

American

noun

the highest concentration of a specific air pollutant at a particular outdoor location, in a specified unit of time, that is not considered hazardous to humans.

The ambient air standard for gas X is 3 parts per million per hour.

Etymology

Origin of ambient air standard

First recorded in 1970–75

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.