129 A Novel Controlled Test Atmosphere Generation System for the Exposure Assessment Method Setup and Validation

Abstract

Abstract Active sampling and analytical methods for the exposure assessment to chemical compounds have to be validated prior to be used on field. Requirements for the evaluation of these measuring procedures are specified in the ISO 22065 standard and include experiments to be done with a dynamic system for generating known concentration of gas and vapour in air under controlled conditions. Unfortunately, laboratories are rarely equipped with this kind of system and they have to carry out manual spiking of samples with a liquid micro-syringe, which is time consuming and source of uncertainty. In order to meet the requirements for accurate methods, we have designed and developed a fully automated generation system -called COMET generation system- that allows producing simultaneously four distinct concentration levels of gaseous pollutants and to perform automated multiple samples in each concentration branch according to the ISO 22065 standard compliance. The system is based on innovative pollutant generation, temperature and humidity control and multiple sampling technologies to be contained under a fume hood. The design of the system allows performing all the required sampling within a week whereas manual spiking need several weeks and excluding some important experiments where the temperature and the moisture have to be controlled. An online gas chromatograph or an Infrared photoacoustic analyzer determine the actual concentration in each concentration level branch. Two different methods were validated with both manual spiking and with the COMET system and the results were similar. Repeatability and overall uncertainty are significantly lower with the COMET system.