Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/20942
Title: Comprehensive Study of Particulate Emission from Laser Printers
Authors: VALLIAPPAN SELVAM
Keywords: Laser Printer, Ultrafine particles, Volatile organic compounds, Health effects and mitigation
Issue Date: 9-Jul-2010
Source: VALLIAPPAN SELVAM (2010-07-09). Comprehensive Study of Particulate Emission from Laser Printers. ScholarBank@NUS Repository.
Abstract: Laser printers are one of the common indoor equipment in schools, offices, and various other places. Recently, laser printers have been identified as a source of indoor contaminants such as ultrafine particles (UFPs, aerodynamic diameter = 100 nm) and Volatile Organic Compounds (VOCs). The health risk that the contaminant posed to human exposure is determined by the extent to which the particles can travel into human respiratory pathway. A number of studies have been published earlier on the emissions of indoor air contaminants from laser printers. In the present study the general emission behavior of a laser printer was examined by conducting particle size measurements and measurement of black carbon contents using Fast Mobility Particle Sizer (FMPS) and Aetholometer respectively inside a test chamber. Chamber tests were done in this study on fresh emissions of particles from laser printers in a controlled environment. In addition, particulate emissions in the real-time environment of an office equipped with printers were assessed to quantify the relationship between operating conditions of printers and the characteristics of particles emitted. Complementary experiments were carried out in a commercial printing room with identical measurement techniques to quantify the number concentration, particulate matter (PM2.5) mass concentrations, black carbon (soot) concentration, temperature and relative humidity. The results revealed a significant increase of particle number concentrations in indoor air, especially for ultrafine particles. In addition, selected VOCs were analyzed during different printing modes to investigate the indoor chemistry during printing which could lead to the formation of ultrafine particles. VOCs such as styrene, ethyl benzene, o, m, p-xylenes were higher during peak printing hours than other times of the day which could be due to their release from toner materials. The measurement and analysis of particle size distributions, characteristics and composition in laser printer emissions provided insights into probable formation mechanisms. The particle concentrations increased linearly with an increase in the number of pages printed. The number concentrations have increased around ~2 to 6 times compared to the background concentration. At reduced ventilation rates, nuclei mode particle (diameter < 50 nm) concentrations increased several times with a peak modal diameter of 20 nm. Laser printers placed in a relatively small office with poor ventilation can cause particulates to build up and persist in the indoor environment. This study concludes that UFP concentrations in a room containing laser printers could be high enough to be of concern in terms of indoor air quality and human health. The indoor air quality implications of this study are further discussed in detail.
URI: http://scholarbank.nus.edu.sg/handle/10635/20942
Appears in Collections:Master's Theses (Open)

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