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: Prashant Kumar
Aerosol and Air Quality Research 01/2013; 13:911-921. · 2.66 Impact Factor
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ABSTRACT: Identifying air pollutants that pose potential adverse health exposures in retail stores will facilitate exposure mitigation. Assessing the role of ventilation in mitigating this exposure is important to understand the energy implications of maintaining acceptable indoor air quality. In this work, we summarize results from 28 papers that report ventilation rates and/or pollutant concentrations in retail stores. These results were compared to available standards as well as data collected in non-retail environments. The findings of this review are: (1) half of the stores tested met/exceeded ASHRAE Standard 62.1-2010 (ASHRAE 2010a; or California Code of Regulations Title 24-2010) for ventilation; (2) PM2.5, acrolein, formaldehyde, and acetaldehyde exceeded their established, most conservative limits/reference exposures for a few of the stores tested in the United States, and outside the United States, researchers reported PM10, benzene, and trichloroethylene as additional pollutants found at concentrations that exceeded their limits; (3) alternative control methods would be more effective, and possibly more economical, than ventilation; (4) meeting or exceeding the ventilation requirements does not necessarily negate the presence of pollutants above their suggested limits; and (5) using disability-adjusted-life-year (DALY) as a metric of disease burden, two pollutants were identified as priority hazards in retail stores: PM2.5 and acrolein. Control strategies should focus on decreasing exposure of retail employees to these pollutants generated indoors or infiltrated from outdoors.HVAC&R RESEARCH 02/2014; 20(2). DOI:10.1080/10789669.2013.869126 · 0.75 Impact Factor