Indoor concentration measurements of particulate matter at a pig fattening facility: Comparison and equivalence tests with different sampling instruments and measuring techniques

The objective was to test the comparability and equivalence of different techniques for the measurement of particulate matter concentrations (PM10, PM2.5, and PM1) in heavy PM loaded agricultural aerosols like the indoor climate of a pig fattening facility. The equivalence assessments were performed according to EN 132051 (2002). Furthermore, the instrument performances were evaluated with regard to temperature and relative humidity (RH) at the sampling site, sampling duration and PM concentration levels. Four types of instruments were included in these experiments: a reference instrument according to EN 123412 (1998), a PM10 impactor, a beta attenuation monitor and two similar spectrometers. In most cases, comparable results in PM10 concentrations were found between instruments. Furthermore, for this fraction, equivalence according to EN 132051 was established with the spectrometers. For PM2.5 and PM1, the measured concentrations were less comparable between the different instruments, and consequently no equivalence could be shown. In general, slightly lower PM10 concentrations were obtained by the samplers with an impaction separation technique (Reference Sampler, BAM and Impactor). In contrast, for PM1 and PM2.5, the impaction techniques measured concentrations up to 25 times higher than the spectrometers tested. The latter phenomenon was probably due to overload of the impaction plates of the samplers.