英语释义
1. the level of concentration of a harmful or toxic substance or contaminant (such as lead, asbestos, benzene, or radiation) that when exceeded is considered sufficient to warrant regulatory or remedial action
Two-thirds of the more than 6,000 homes it tested in 2003 had lead levels exceeding the Environmental Protection Agency's “action level”—the safety level at which federal law requires a water system to take prompt steps to reduce lead levels and notify the public.
— Erik D. Olson, Washington Post, 8 Feb. 2004 Future clam digs are dependent on marine toxin levels, but the first set of samples dug last Sunday showed all results were still below the action level.
— Mark Yuasa, Seattle Times, 25 Oct. 2009