Photocopiers and printers are commonly used electronic devices in offices, industrial settings, and households. These devices are a potential source of indoor air pollutants as they emit nanoparticles (NP), and other gaseous pollutants.
Past research has focused on emission of volatile organic compounds (VOCs), ozone, and other gaseous pollutants, results of which prompted improved technologies that reduced exposures to such pollutants (e.g. ozone).
Some elements of toner are volatile organic compounds (VOCs), which persist in the air for long periods of time. Some of the VOCs associated with photocopiers are benzene and decane (carcinogens), toluene (which can cause irritation and drowsiness), and xylene (which can cause kidney damage).
Areas near laser printer and copiers which are not adequately ventilated can contain dangerous levels of carbon monoxide, and poorly maintained machines can produce nitrogen oxide, a gas that produces similar effects to carbon monoxide and also affects the central nervous system in the presence of ozone.
More recently, the focus has shifted to the investigation of nanoparticle emissions, their origin and chemical composition. The peak size distribution of emitted nanoparticles is often below 50Â nm, whereas the toner particles are several microns large. Nanoparticles emitted during photocopier operation are formed during the image transfer process.
A study in the Journal Nanotoxicology, investigate for the first time early human responses following a day's exposure to nanoparticles from photocopiers. Following exposure, several pro-inflammatory cytokines were elevated by up to 10 fold compared with pre-exposure levels and remained elevated for up to 36 hours. The nanoparticles from the hotocopiers induced upper airway inflammation and oxidative stress.
The most shocking fact about the toxins released by these machines is that very short exposure can cause health damage for days.
The chemical composition of nanoparticles emitted from photocopiers is best described as a mixture of organic compounds and inorganic metal oxide additives and reflects the complex toner chemistry in select copiers and printers.
The inorganic fraction of airborne NP varies with the toner formulation and may contain variable amounts of silicon (Si), sulphur (S), titanium (Ti), iron (Fe), chromium (Cr), nickel (Ni), zinc (Zn) and possibly other elements, which were also found in toners. They more likely originate from metal oxide additives in toners (e.g. fumed silica, titania, magnetite), associated impurities, and possibly the paper.
Other studies reported significant DNA damage and chromosomal aberrations in the peripheral blood samples of workers occupationally involved in photocopying.
More recently, Tang et al. investigated cytotoxicity and genotoxicity of laser printer emissions in human lung cells. They found that emissions of two out of five printers were genotoxic meaning they cause mutations within DNA.
Another study in the Journal Particle and Fibre Toxicology, show that nanoparticles from toners induced production of several inflammatory cytokines and chemokines in three human cell lines. The study reinforced earlier conclusions that copier-emitted nanoparticles are directly responsible for the induction of pro-inflammatory responses, likely through the oxidative stress pathway.
The tribo-electric explosions needed as result of the static electricity are quantitatively very small to generate the necessary inflammatory responses to produce damage. The firing necessary to produce just one page can theoretically cause the damage NP cloud that can affect the lungs for up to two days.
April McCarthy is a community journalist playing an active role reporting and analyzing world events to advance our health and eco-friendly initiatives.