Measurement of Indoor Air Emissions from Dry-Process Photocopy Machines

Abstract

Presently, no standard test method exists to evaluate the various emissions from office equipment (e.g., ozone, volatile organic compounds, inorganic gases, and particulates) so it is difficult to compare data from different studies.1 As a result, the authors are developing a standardized guidance document for measuring indoor air emissions from office equipment. The ultimate goal is to apply the test method to better understand emissions from office equipment and to develop lower emitting machines. This paper provides background information on indoor air emissions from office equipment with an emphasis on dry-process photocopy machines. The test method is described in detail, along with the results of a study to evaluate the test method using four dry-process photocopy machines. The results from this study indicate that the test method provides acceptable performance for characterizing emissions; that it can adequately identify differences in emissions between machines both in compounds emitted and their emission rates; and that it is capable of measuring both intra- and inter-machine variability in emissions. Challenges and complications were encountered in developing and implementing the test method. These included heat generation, which can cause large increases in chamber temperature; finite paper supplies for photocopy machines, which limit test duration; varying power requirements that may require changes in chamber electrical supply; and remote starting of the machines, which is necessary to maintain chamber integrity. Results show that dry-process photocopy machines can produce emissions of ozone and volatile organic compounds that can potentially have a significant impact on indoor air quality. For the four machines tested in this study, the compounds with the highest emission rates overall were ethylbenzene (28,000 µg/hour), m,p-xylenes (29,000 µg/hour), o-xylene (17,000 µg/hour), 2-ethyl-lhexanol (14,000 µg/hour), and styrene (12,000 fig/hour). Although many of the same compounds tended to be detected in emissions from each of the four photocopiers, the relative contribution of individual compounds varied considerably between machines, with differences greater than an order of magnitude for some compounds.

Ozone in Indoor Environments: Concentration and Chemistry

“…Although various photocopying processes produce ozone, most manufacturers incorporate some type of filtration system (e.g., activated carbon filters) to reduce the amount of ozone emitted to the surrounding air. Leovic et al (1996) have measured ozone emissions from several different dry-process photocopiers. Their work demonstrates that ozone emissions can increase between periods of routine maintenance.…”

Indoor pollutants emitted by office equipment: A review of reported data and information needs

“…Laser printers and photocopiers generate ozone in varying amounts (Smola et al, 2002;Lee et al, 2001;Leovic et al, 1996;Leovic et al, 1998). Toner and paper dust from printing devices become airborne resulting in the generation of respirable particles, including ultrafine aerosol particles , Lee et al, 2001).…”

“…Printers and photocopiers also are sources of volatile organic compounds (VOCs), which derive at least in part from the toner that undergoes heating during the printing process. VOCs identified in the emissions from printing and copying devices include chemicals listed on the State of California's Toxic Air Contaminants (TACs) list (OEHHA, 2000), such as benzene, toluene, ethylbenzene, xylenes, and styrene, formaldehyde and acetaldehyde (Lee et al, 2001; Leovic et al, 1996;Leovic et al, 1998). The plastic covers of video-display units (VDUs) have been shown to contain and emit triphenylphosphate and other organophosphate esters used as flame retardants (Carlsson et al 2000).…”

Quantification of Ozone Levels in Indoor Environments Generated by Ionization and Ozonolysis Air Purifiers

“…Depending on the design, some ionic air purifiers can emit O 3 with a rate of a few milligrams of O 3 per hour, which is comparable to the amount of O 3 emitted by dry-process photocopiers during continuous operation. 6,7 Ozonolysis air purifiers typically produce several hundred milligrams per hour of O 3 with a goal of oxidizing VOCs in indoor air. However, O 3 reacts exceedingly slowly with most saturated VOCs.…”