Exposure assessment of nanomaterials at production sites based on short time sampling : strategy & methodology of the STS-EA approach
Résumé
The use of nanomaterials in various end products allows to achieve new and innovative properties which has resulted in their large scale deployment leading to an large exposure estimated to 300 000 to 400 000 european workers (European Commission 2012). A new measurement approach is required to assess more precisely nanoparticle exposure at the workplace. An important aspect of the measurement campaign presented in this work is the sampling duration of the exposure assessment. NP or NOAA exposures are believed to be usually a succession of several short-term exposures (Pietroiusti 2014). In addition, short-term aerosol measurements permit the identification of nanoparticle release points, thus designing source control at workplace. To satisfy these demands, a relevant measurement strategy must be able to distinguish the NP or NOAA from the particulate background and to take into account the inhalable NOAA i.e. below 10 μm in size during a very short sampling time. Therefore the assessment of exposure measurement should be able to deal with these issues and must be able to provide recommendations of nanosafety to all stakeholders. Mini particle sampler (MPS, Ecomesure) is a new equipment making possible such an improvement (R'mili 2013). The objective of the present work is to propose a global approach to assess the nanoparticle exposure assessment at workplaces (Figure 1). The methodology and strategy of the global approach is to perform the measurement campaigns using the Short Time Sampling named STS merging the tiered approach (Consent Report 2011) and the INERIS-CEA-INRS (INERIS - CEA - INRS 2012.) approach. To validate the method the STS approach has been tested on five different nanomaterials as NPs of zirconium dioxide (ZrO2), titanium dioxide (TiO2), silver (Ag); polyamide nanofibers; and multiwalled carbon nanotubes (MWCNT) used in 6 different process lines.