The measurement of workplace aerosol concentrations was previously carried out using a wide range of different instruments in the various countries of the European Union. The agreement of common workplace exposure limits in Europe was rendered difficult by this lack of uniformity in approach, since measurements made in different countries could not be readily compared. In 1993 the European and International standards bodies CEN and ISO agreed standardised conventions for the health-related sampling of aerosols in workplaces. These conventions represented target specifications for instruments used to assess the possible health effects due to inhalation of aerosols. A CEN pre-standard for workplace aerosol samplers, describing test methods to evaluate whether they conformed to the target specifications, was also developed. However given the state of the art at the time the prestandard was written, many aspects of the test protocols had only been applied in limited circumstances and thus their general practicability was not proven.
The purpose of the research project was to apply the test protocols laid down in the CEN prestandard, in order to identify problems with the experimental, statistical and mathematical procedures, and to suggest ways in which they could be improved. The main objectives of the project were:
To examine the test protocols for personal inhalable aerosol samplers described in the CEN pre-standard, and the potential for simplifying them;
To provide information to assist in revision of the CEN pre-standard and develop a full European standard for workplace aerosol sampler performance.
To investigate the performances of eight types of personal inhalable aerosol sampler, either currently in use or proposed for use in various European countries.
The project successfully identified both strengths and weaknesses in the test protocols and led to a number of recommendations for revision of the prestandard, although some important aspects of the prestandard were identified as outside the scope of the project and requiring further work. Since the project was completed the CEN standard has been prepared and is currently in the voting process. Research to fill the identified gaps in knowledge has been initiated on a national or collaborative basis. The test results obtained for the sampler types evaluated in the project have led to revisions of workplace sampling guidance in several European countries.
Tests on eight types of personal inhalable aerosol sampler were carried out, followed the protocols recommended in the European prestandard. The work allowed the problems in applying these protocols to be identified and where possible resolved. The data obtained from the experiments were analysed to calculate the performance characteristics of the eight sampler types, to enable comparisons with the inhalable sampling convention, and between sampler types themselves. The project findings and recommendations were discussed within CEN.