Nanoparticle Exposure at Commercial Photocopy Centers and the Need for Hazard Awareness and Control.

Background: Hardcopy devices (HDs) (laser printers/photocopiers) use nano-enabled toners and emit nano-particles (PM_0.1) in significant quantities over indoor background levels and many outdoor environments. PM_0.1 emissions are chemically complex mixtures of VOCs, metals, and organic carbon that include engineered nanomaterials (ENMs), which can be traced directly to the toner. In-vitro studies suggest HD emissions induce DNA damage, oxidative stress, and have toxic potency similar to welding fume. Human exposure studies mirror these findings. There is little user awareness or control of the hazard, and no guidelines protecting workers or patrons from overexposure.

Objective: To characterize PM_0.1 emitted from photocopiers, and survey the work environment with regard to indoor air quality (IAQ), emissions control and PM_0.1 exposures at the copier and at occupant workstations.

Methods: Fifteen high-volume photocopy centers were randomly visited to measure common IAQ parameters, ventilation, and PM_0.1. Week long sampling for SEM/TEM analysis, elemental analysis, and particle size distribution measurements were conducted at eight centers.

Results: Geometric mean particle concentrations at the workstation ranged from 1,900 to 23,000 particles per cubic centimeter (pt/cm³) (2-12 times greater than ambient concentrations), with transient peaks over 700 times background. PM_0.1 diameters ranged from 24-34 nm. Several ENMs, were found in toners and emitted PM_0.1. Inadequate ventilation was noted in 46% of the centers studied. PM_0.1 is significantly correlated with the number of copies produced.

Conclusions: End-user risk of exposure to extremely high PM_0.1 concentrations and ENMs are common. We noted continued lack of emissions control and occupant awareness of the hazard.