This guide establishes best practice procedures for sampling and analysing environmental samples and is designed to assist licence holders, consulting analysts and industry with background information and guidance on performance monitoring for environmental purposes. The guidelines must be followed whenever testing or monitoring is undertaken for any purpose required by the Environment Protection Act 1970. The guidelines will also be invaluable to any company or agency that wishes to obtain an accurate assessment of the impact of its activities on the environment.This guideline replaces EPA Publication 440 'A guide to sampling and analysis of air emissions'.