a: parts per trillion ~
b: microscopic mildew spore
What:
"One industry expert I consulted explained it to me like this: if parts per million is like finding the proverbial needle in a haystack, parts per trillion is like finding a microscopic mildew spore on a piece of chaff in that haystack."
Useful?
Writer: Lynn Freeman
LCC:
Where:
Date: May 12 2016 6:30 PM
# 9906 Critique Analogy