The 2020 questionnaire survey by Omari Shekaftik and colleagues of 15 nanotechnology laboratories in Tehran, Iran, found pervasive reliance on minimal exposure controls — general or unfiltered local ventilation, surgical masks rather than certified respirators — in laboratories whose work is dominated by carbon nanotubes, dispersible powders, and suspensions, and found that only 20–40% of laboratories owned any instrument for measuring or detecting airborne nanoparticles. The survey performed no airborne measurements, so its recommendations rest on international guidance rather than local exposure evidence. The open problem it leaves is the empirical and translational agenda required to turn these descriptive findings into verified exposure reductions: task-based baseline characterization of airborne nanomaterial exposures during representative laboratory tasks; quantitative, locally valid comparison of the candidate engineering controls (gloveboxes, HEPA-filtered local exhaust ventilation, dedicated nanomaterial rooms); and feasible nanomaterial-specific safety-data-sheet and SOP templates, PPE and training programs, and institutional adoption mechanisms for resource-limited research groups. No published study is known to have measured airborne nanomaterial exposures in Iranian nanotechnology research laboratories, and the only field-measurement study of nanomaterial control effectiveness to date (Singapore, nano-titanium-dioxide, 2025) covers neither Iran nor the carbon-nanotube and powder tasks that dominate these laboratories.

Background

Engineered nanomaterials (ENMs) are substances deliberately manufactured with at least one dimension between roughly 1 and 100 nanometres — in the laboratories studied here, chiefly multi-walled and single-walled carbon nanotubes (CNTs, fibrous carbon structures whose inhalation hazard is treated as asbestos-like), metallic and metal-oxide powders, and nanoscale suspensions and emulsions. Weighing powders, sonicating suspensions, synthesizing materials, and cleaning equipment can release nanoscale particles into laboratory air. Because the inhaled dose of nanoscale material, rather than bulk mass alone, drives the concern, exposure assessment for ENMs combines direct-reading instruments that count airborne particles (for example a condensation particle counter, which grows particles until they are optically detectable), material-specific filter sampling and analysis (for CNTs, elemental carbon analysis per NIOSH Method 5040, a standard method of the US National Institute for Occupational Safety and Health), and near-field/far-field designs that subtract the ambient ultrafine-particle background from workplace measurements.

Occupational ENM control follows the hierarchy of controls, an ordering of interventions from most to least protective: elimination, substitution, engineering controls, administrative controls, and personal protective equipment (PPE). The engineering controls relevant here are gloveboxes (sealed enclosures with integrated gloves), local exhaust ventilation (LEV) fitted with HEPA filters (high-efficiency particulate air filters capturing at least 99.97% of 0.3-micrometre particles), and dedicated nanomaterial work rooms with pressure control. Where quantitative exposure data are missing, control banding tools such as CB NanoTool assign a risk band from material hazard and exposure probability and prescribe a corresponding control level. Administrative instruments include nanomaterial-specific safety data sheets (SDS, the standardized hazard-information documents accompanying chemicals) and standard operating procedures (SOP); respiratory protection against nanoparticles requires certified filtering-facepiece respirators (N95, FFP2, FFP3, or N100 classes) with fit testing, not ordinary surgical masks.

In 2020 Omari Shekaftik and colleagues surveyed 15 nanotechnology laboratories in Tehran (recruited through the Iran Nanotechnology Laboratory Network) using a validated questionnaire completed by laboratory supervisors. Only a third of the laboratories had a nanomaterial-specific safety and health policy; engineering controls were dominated by general room ventilation and unfiltered single-point local ventilation (gloveboxes present in 33.3% of laboratories, HEPA-filtered ventilation in 20.0%, dedicated nanomaterial rooms in 13.3%); respiratory protection relied largely on common medical masks (80.0%), with FFP2 respirators in 20.0% and N100 in 13.3%; and only 6 of 15 laboratories owned any measurement instrument and 3 of 15 any detection instrument for airborne nanoparticles. The study performed no airborne measurements itself, and respondents attributed the minimal controls to lack of technology, funds, and information.

Internationally, guidance on nanomaterial handling is abundant but uneven: a 2024 review by the same research group catalogued 31 guidelines from 27 organizations and concluded that the appropriate type and method of engineering controls and PPE still needs to be resolved against primary evidence, and a 2026 exchange in the same journal debates how far the conventional hierarchy of controls applies to nanomaterial workplaces at all. Field quantification of control effectiveness is young: the Exposure Control Efficacy Library (ECEL) aggregates literature-derived control-efficiency benchmarks, and a 2025 Singaporean field study of seven nano-titanium-dioxide workplaces — including fume-hood laboratories — combined real-time particle-number monitoring with ECEL priors in a Bayesian framework, finding laboratory observed control efficiencies of 0.249–0.806 and showing that the temporal stability of a control, not only its peak efficiency, governs real protection. In Iran, follow-up work by the same group through 2026 — a knowledge-attitude-practice study of researchers (a survey type measuring what workers know, believe, and actually do), a wider survey of nanotechnology laboratories in 8 universities of medical sciences together with a student-symptom survey, and control-banding risk assessments of nanomedicine research laboratories — has remained questionnaire- and risk-band-based, and a 2026 analysis of chemical safety in Iranian universities documents that these institutions operate without dedicated regulations. Consequently, for the Tehran laboratory network the survey described, there exists neither a measured baseline of airborne nanomaterial exposure during representative tasks nor any locally valid quantification of how much exposure the recommended controls would actually remove.

Problem Statement

The problem the 2020 Tehran survey leaves open is to convert its descriptive findings into verified exposure reduction for the resource-limited nanotechnology research laboratories it studied, through three linked components that jointly serve this single objective: (1) establish the baseline of airborne nanomaterial concentrations and worker exposures during representative synthesis and handling tasks involving the dominant materials in these laboratories — carbon nanotubes, dispersible powders, and suspensions — using direct-reading particle instrumentation and material-specific sampling with ambient-background correction, since only 20–40% of the laboratories owned any measurement or detection equipment and no such measurements exist; (2) quantify, under these local conditions, the reduction in worker exposure achievable with the candidate engineering controls the survey recommends — gloveboxes, HEPA-filtered local exhaust ventilation, and dedicated nanomaterial work rooms — so that scarce investment can be prioritized against evidence rather than guideline default; and (3) derive and evaluate the locally feasible translational instruments: nanomaterial-specific safety-data-sheet and SOP templates compatible with national standards, cost-effective PPE programs (respirator selection, fit testing, maintenance) and training capable of producing sustained behavior change among researchers, and the institutional mechanisms — national guidance, funding support, inspection, or accreditation — by which adoption across the heterogeneous laboratories of the Iran Nanotechnology Laboratory Network can be achieved. For the dominant materials and tasks, the baseline component is a proposed task-based measurement design rather than executed measurements, and the control-efficiency estimate for each candidate engineering control is quantitative, with stated uncertainty, resting on stated priors and explicit transfer assumptions because no locally measured values exist.

References

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