Objective
Occupational exposure of industry workers to potentially harmful vapours may be highly variable from one worker to another. Therefore periodic monitoring of the exposure of each individual worker is legally required. Community legislation is being developed; a draft CEN standard requires an overall accuracy of 30 %; as the sampling is expected to be the larger source of error, analyses should be accurate to within appr. 10 %. Intercomparisons with leading laboratories from government and from chemical industry have shown much larger errors.
Therefore several projects were started to improve the accuracy of workplace air monitoring. The intention was to cover a limited number (e.g. 10) of classes of compounds, which were measured in a wide range of industries and which covered the various types of technical difficulties encountered. Aromatic hydrocarbons were selected for the first project in this series, as they are universally used as solvents (toluene, xylene,...) or present in gasoline and exhaust gases (benzene).
"Personal monitoring" of exposure to aromatic hydrocarbons is usually performed by trapping vapours on a sorbing agent, from wich they are desorbed either by heat (a) or by solvent extraction (b) for the final gas chromatographic determination.
RESULTS
Three successive intercomparisons were organised, each followed by a meeting where the measurement methods were discussed. The main sources of error were:
- evaporation of liquids during the preparation of the standard solutions
- use of uncalibrated equipment (e.g. syringes)
- not readily detected instrument malperformances (leaks in the thermal desorber, malfunctioning analytical balance; unoptimised flame ionisation detector).
A reference material was certified consisting of Tenax tubes with: (1.053 +/- 0.014) ug benzene; (1.124 +/- 0.015) ug toluene and (1.043 +/- 0.015) ug m-xylene. Certification report : EUR 12308, 1990.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- engineering and technologyenvironmental engineeringenergy and fuelsliquid fuels
- natural scienceschemical sciencesorganic chemistryhydrocarbons
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Topic(s)
Data not availableCall for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
Arnhem
Netherlands