Physicochemical and Toxicological Characterization of Engineered Nanoparticles Emitted from Laser Printers: Environmental Health Implications?

S. Pirela, G. Pyrgiotakis, G. Sotiriou, B. Zhao, D. Bello, P. Demokritou
Harvard School of Public Health, US

Keywords: nanoparticles, laser printers, toner powder

Summary:

Use of laser printers has been associated with emission of particulate matter (PM), ozone and VOCs. Recently, there have been concerns due to incorporation of engineered nano materials (ENMs) into toner formulations for quality improvements; however, implications on exposures and environmental health are unknown. In this study, an exposure system was developed to perform a physico-chemical and toxicological characterization of printer emitted particles (PEPs). Eleven commonly used printers were evaluated and ranked based on PM emission profiles utilizing real time and integrated instrumentation. Morphological examination of the airborne PM and toner powder was performed using TEM/SEM and surface chemistry assessed using EDS and FTIR. Furthermore, collected PM from the 6 highest emitting printers was used in toxicological and chemical characterization. Results show peak PEPs emissions are brand-independent and varied between 3,000 to 1,200,000 particles/cm3 with modal diameters ranging from 49 to 208 nm. Moreover, we confirmed toner formulations contained materials of complex chemical composition and, more importantly, it was illustrated that during printing, ENMs from the toners become airborne. Lastly, preliminary toxicology data showed PEPs may induce biological responses in the lungs of those exposed to them.