Evaluation of a Test Method for Measuring Indoor Air Emissions from Dry-Process Photocopiers

Abstract

A large chamber test method for measuring indoor air emissions from office equipment was developed, evaluated, and revised based on the initial testing of four dryprocess photocopiers. Because all chambers may not necessarily produce similar results (e.g., due to differences in sink effects, temperature and humidity control, air exchange, pollutant monitoring, and measurement biases), a preliminary four-laboratory evaluation of the revised test method was conducted. To minimize variability, the evaluation used a single dry-process photocopier that was shipped to each of the four laboratories along with supplies (i.e., toner and paper).The results of this preliminary four-laboratory evaluation demonstrate that the test method was used successfully in the different chambers to measure emissions from dry-process photocopiers. Differences in chamber design and construction appeared to have had minimal effect on the results for the volatile organic compounds (VOCs). IMPLICATIONSThe paper discusses a four-laboratory evaluation of a large chamber test method developed by the authors to measure indoor air emission from dry-process photocopies. The results of the evaluation demonstrate that the test method was used successfully in the four different chambers to measure emissions from a dry-process photocopier, and that differences in chamber design and construction had minimal effects on the results for the volatile organic compounds (VOCs). The method can be used by manufacturers and others in order to evaluate emissions from copiers.Perhaps more important than the chamber itself is the sample analysis as identified by duplicate samples that were analyzed by a different laboratory. Percent relative standard deviation (%RSD) was used to provide a simplistic view of interlaboratory precision for this evaluation. Excluding problems with suspected analytical bias observed from one of the laboratories, the precision was excellent for the VOCs with RSDs of less than 10% in most cases. Less precision was observed among the laboratories for aldehydes/ketones (RSD of 23.2% for formaldehyde). The precision for ozone emission rates among three of the laboratories was excellent (RSD of 7.9%), but emission rates measured at the fourth laboratory were much higher.

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

“…Volatile organic chemicals (VOCs) were typically collected on sorbent tubes filled with Tenax-TA® (Leovic et al 1998;Nakagawa et al 2003) or with Tenax-TA in combination with other sorbent material such as Ambersorb and charcoal (Brown 1999). …”

“…In all cases, VOCs were identified and quantified by GC/MS. Volatile carbonyls were collected in DNPH-coated silica cartridges (Leovic et al 1998;Nakagawa et al 2003) or by direct absorption in an aqueous solutions with further derivatization (Brown 1999). …”

“…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).…”

“…In most cases, we report the sum of VOC concentrations determined as ΣVOC. All other samples were collected on various substrates that integrate emissions over a defined period.Speciation of organic analytes of interest was carried out subsequently by chromatography after sample preparation steps involving extraction and, in some cases, derivatization.Volatile organic chemicals (VOCs) were typically collected on sorbent tubes filled with Tenax-TA® (Leovic et al 1998;Nakagawa et al 2003) or with Tenax-TA in combination with other sorbent material such as Ambersorb and charcoal (Brown 1999).Other VOC collection methods used a canister (Lee et al 2001). In all cases, VOCs were identified and quantified by GC/MS.…”