An investigation into the characteristics and formation mechanisms of particles originating from the operation of laser printers
ABSTRACT While current research has demonstrated that the operation of some laser printers results in emission of high concentrations of ultrafine particles, fundamental gaps in knowledge in relation to the emissions still remain. In particular, there have been no answers provided to questions such as the following: (1) What is the composition of the particles? (2) What are their formation mechanisms? (3) Why are some printers high emitters, while others are low? Considering the widespread use of printers and human exposure to these particles, understanding the process of particle formation is of critical importance. This study, using state-of-the-art instrumental methods, has addressed these three points. We present experimental evidence that indicates that intense bursts of particles are associated with temperature fluctuations and suggest that the difference between high and low emitters lies in the speed and sophistication of the temperature control. We have also shown, for the first time, that the particles are volatile and are of secondary nature, being formed in the air from VOC originating from both the paper and hot toner. Some of the toner is initially deposited on the fuser roller, after which the organic compounds evaporate and then form particles, through one of two main reaction pathways: homogeneous nucleation or secondary particle formation involving ozone.
- SourceAvailable from: PubMed Central[show abstract] [hide abstract]
ABSTRACT: Inhalation of carbon nanoparticles (CNP) from toner dust has been shown to have impact on the respiratory health of persons exposed. Office printers are known emitters of CNP. We report about a female open office worker who developed weight loss and diarrhoea. Laparoscopy done for suspected endometriosis surprisingly revealed black spots within the peritoneum. Submesothelial aggregates of CNP with a diameter of 31-67 nm were found by scanning and transmission electron microscopy in these tissue specimens. Colon biopsies showed inflammatory bowel disease with typically signs of Crohn disease, but no dust deposits. Transport of CNP via lymphatic and blood vessels after inhalation in the lungs has to be assumed. In this case respiratory symptoms were not reported, therefore no lung function tests were done. We have shown that workers with toner dust exposure from laser printers can develop submesothelial deposition of CNP in the peritoneum. Impact of toner dust exposure on the respiratory health of office workers, as suspected in other studies, has to be evaluated further.Diagnostic Pathology 01/2010; 5:77. · 1.85 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Laboratory tests of particle removal were performed with a pair of carbon fiber ionizers installed upstream of a glass fiber air filter. For air flow face velocities of 0.4, 0.6, and 0.8 m/s, the overall particle removal efficiencies of the filter for all submicron particles were 17%, 16%, and 14%, respectively, when the ionizers were not turned on. These values increased to 27%, 23%, and 19%, respectively, when the ionizers were used to generate ions of 6.0 × 109 ions/cm3 in concentration. The carbon fiber ionizers were then installed in front of a glass fiber air filter located in a heating, ventilation, and air-conditioning (HVAC) system. Field tests were performed in a test office room with a total indoor particle concentration of 2.2 × 104 particles/cm3. When the flow rate was 75 cubic meters per hour (CMH), the steady-state values of the total indoor particle concentrations using the glass fiber air filter with and without ionizers decreased to 0.87 × 104 particles/cm3 and 1.15 × 104 particles/cm3, respectively, resulting in a 25% decrease of the ionizer effect. When the operation flow rate was increased to 115 and 150 CMH, the effect of the ionizer decreased to 19% and 17%, respectively. These experimental data match the results calculated using a mass-balance model whose parameters were determined from laboratory tests.Building and Environment. 01/2011;