The National Environment Protection Council made the National Environment Protection (Air Toxics) Measure in 2004. The monitoring investigation levels are the concentrations of an air toxic which, if exceeded, requires an appropriate form of further investigation and evaluation.
|Pollutant||Averaging period||Monitoring investigation levels|
Annual: the annual average concentrations are the arithmetic mean concentrations of 24-hour monitoring results.
24 hours: monitoring over a 24-hour period is conducted from midnight to midnight.
ppb: parts per billion (for every billion litres of air there is one litre of the pollutant).
ng/m3: nanograms per cubic metre (1 billionth of a gram per cubic metre).
This page was copied from EPA's old website. It was last updated on 23 October 2013.
Reviewed 25 November 2021