Emission Tests From Office Equipment in the Indoortron Environmental Chamber

Abstract

P-290 Abstract: The evaluation of actual exposure concentrations in the office environment is very complex and depends strongly on operational conditions (quantity of machinery, mode and time of operation) as well as the characteristics of the office room (dimensions, ventilation, etc). A series of tests were performed to evaluate emissions from office equipment (laser printers). The experiments were carried out at the Indoortron facility, a 30 m3 walk-in type environmental chamber. The test protocol applied in this study makes it possible to evaluate emissions released following several printing scenarios during normal operation of the machines as well as in standby mode. Two in-use printers, one black & white (B&W) and one color printer, plus one new color printer labeled as a low emissions printer, were tested under conditions simulating a “real world setting”. Inorganic compounds such as ozone, nitrogen oxides, carbon monoxide, volatile organic compounds (VOC) and carbonyls under static conditions (no ventilation), 0.5 ach (air changes per hour) and 1 ach were measured applying different scenarios that cover several printing rates, e.g. 20, 100 and 200 prints/hour, and total number of copies processed (e.g. 100–200). Dust was also monitored in a few experiments. During the printing processes in our studies, indoor air concentrations of inorganic compounds were very low: maximum levels measured for ozone, NOx and CO were 6 ppb (10 ug/m3), 10 ppb (ca. 18 ug/m3) and 1 ppm (ca. 1.2 mg/m3) respectively. Among the low molecular weight carbonyls, formaldehyde was the most abundant in all printing scenarios with indoor air concentrations up to 11 ug/m3. Total volatile organic compounds (TVOC) from color printers reach indoor concentrations as high as 203 ug/m3 (200 prints/hour, at 0.5 ach). The corresponding values for B&W printers were about ten times lower. Under static conditions (no ventilation) accumulation for TVOCs in indoor air was found to be significantly higher (up to 50%), in particular for color printers. Preliminary results concerning the particulate matter indicate high number of particles smaller than 1 um measured during the printing process at both test ventilation rates (0.5 and 1 ach). Common VOCs emitted from laser printers while the machine is running include aldehydes, styrene, xylenes, and other aromatics C6-C12 alkanes. Additional studies show that toner composition as well can affect the VOC emissions, both qualitatively and quantitatively.