What Health Risks Does Printing Pose? — Chromatography Explores

Printers are ubiquitous, every home, organization and office has at least one — even allowing for paperless offices. But are they as safe as you think? I’m not talking about getting your tie stuck in the paper feed as it drags a sheet of paper into the mechanism. No, what we’re looking at is the toner used in laser printers. Read on — carefully if you print — to see what the latest research has uncovered about toner and printing.

Toner — more than carbon black

Originally, toner was basically carbon black mixed with a few other chemicals like iron oxides — but as demand for resolution, fineness and print quality have increased the formulation of toner has changed. And this means that today’s toner is described as containing engineered nano-particles or ENPs.

The ENPs are generally polymers that contain other additives such as oxides of iron, copper, silicon and manganese. Some studies have shown that due to their small size these nano-particles could get deep into the lungs and alveoli. This might allow them to pass into the blood stream and induce harmful effects. What happens when you are printing is that these particles are heated and fuse together reducing the risk of inhalation.

Bad reaction to printing

Now a team based at Harvard University — which have been studying these particles for the last five years have taken the research a step further. In a paper published in the journal Environmental Science: Nano — Synergistic effects of engineered nanoparticles and organics released from laser printers using nano-enabled toners: potential health implications from exposures to the emitted organic aerosol — by taking a look at the particles that are generated during the printing process. Printer emitted particles or PEPs.

Whilst work has been carried out on assessing the health risks associated with the ENPs, the researchers suggest that there is a knowledge gap in the risk assessment of exposures to PEPs. They were interested in the molecular changes in the particles — in particular, the change from low molecular weight particles to high molecular weight particles that are considered more hazardous to human health.

Chromatography measures the change

The researchers used nuclear magnetic spectroscopy along with gas chromatography to investigate the changes that occur in the nano-particles during a printing run. The use of chromatography to analyse VOCs is discussed in the article, High-Throughput Residual Solvent and Residual Monomer Analysis Using Selected Ion Flow Tube Mass Spectrometry.

What they found was that low molecular weight aromatic hydrocarbons that were present in the toner interacted with nano-particles — a reaction helped by the high temperatures used when printing — to make higher molecular weight particles. The higher weight particles are more of a health hazard than the lower weight particles in the unused toner.

The team don’t advocate stopping printing, but the presence of possibly carcinogenic molecules in the air around printers raises health concerns and warrants further study.