The Effectiveness of Specific Risk Mitigation Techniques Used in the Production and Handling of Manufactured Nanomaterials: A Systematic Review

Abstract

: Many kinds of manufactured nanomaterials (MNMs) have been developed and used as basic materials of industrial products, and they may pose health risks for workers in not only developed countries but also in developing countries. Few studies have looked at the evidence for effects of controls that mitigate the risk of exposure to MNMs. Therefore, we systematically searched the literature from the year 2000 to 2015. We included studies that compared the use of an exposure control to the situation without such a technique and those that measured the exposure to MNMs as the outcome. In order to evaluate the effectiveness of these controls, we used their "protection factor", defined as the ratio between concentrations without and with the control. We located 1,131 references in PubMed and other lists, and out of these references, 41 studies fulfilled our inclusion criteria. We categorized them as engineering controls such as enclosure, local exhaust ventilation or process automation, and as personal protective equipment (PPE). For enclosure systems we found a protection factor beyond 100. For other engineering controls, the better controls scored 10 to 20, but many cases of local exhaust ventilation had a protection factor of less than 10 and some cases even increased exposure. PPE such as N95 or equivalent filtering respirators had a protection factor of approximately 10 tested with nano-sized aerosols. We conclude that there is low quality evidence that specific engineering controls can reduce exposure to MNMs but that enclosure is considerably more effective. For respiratory protection the evidence is of very low quality due to the lack of field studies. This information can be used to decide about controls when exposure to MNMs exceeds proposed occupational exposure limits or when no toxicological information is available for a MNM.

Effectiveness of nanoparticle exposure mitigation measures in industrial settings

“…A recent review that quantified the efficiency of PPE and engineering controls (Goede et al, 2018), especially for engineered NPs in controlled scenarios such as laboratories, reported that the available data are inconclusive. Previous studies discussed the efficiency of PPE such as protective gloves, clothes, filtering facepieces respirators and half mask respirators (Kim et al, 2006(Kim et al, , 2007Lee et al, 2007;Myojo et al, 2017;Tsai et al, 2010). A review of this literature, based on search terms "nanoparticles", "protective equipment" "ventilation", "extraction"," safety", "mitigation", evidenced that: (i) studies for incidentally-released NPs are less frequent than for engineered ones; (ii) in spite of a great number of studies on PPE efficiency, less information can be found about the effectiveness of applied technical measures, and they refer mostly to laboratory-scale; (iii) the results obtained cannot be easily generalized beyond the specific cases; and (iv) experimental studies at industrial scale constitute a clear research gap.…”

Application of Inorganic Nanomaterials in Cultural Heritage Conservation, Risk of Toxicity, and Preventive Measures

“…During the years working with nanomaterials, various organizations and research groups have constantly been evaluating whether the quality of the masks is effective in controlling access to the organism [580][581][582]. Nowadays, it is possible to access the comparison of specific nomenclatures and selection criteria available for different international organizations [579,[583][584][585][586]. There is even a new trend for creating nanostructured face masks for obtaining nanofibers that can incorporate multifunctional nanomaterials, which consist of polymeric nanofibers fabricated by electrospinning, phase separation, template synthesis, or self-assembly techniques, which include different nanoparticles such as metals (gold, silver, Zn), metal oxide (TiO 2 ), metal composites (CuO-polyacrylonitrile), graphene, or carbon nanotubes [587].…”