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Pollution Prevention Abstracts
Abstract
A laboratory thermal desorption apparatus was used to measure emissions from a number of nominally identical photocopier toners – manufactured for use in a specific model copier – when these toners were heated to fuser temperature (180 - 200 °C). The objective was to determine whether VOC emissions from a toner might be reduced through judicious selection of the process and the raw polymer feedstock used in its manufacture. Tests were performed on: a series of toner and feedstock samples obtained directly from a toner manufacturer, systematically varying process and feedstock; and toner cartridges – from different lots (for which process and feedstock were unknown) – purchased from local retailers. The results showed that the retailer toners consistently had up to 350% higher emissions of some major compounds, and up to 100% lower emissions of others, relative to the manufacturer toners (p<0.05), probably due to differences in process and/or feedstock. The manufacturer toners showed essentially no effect of process or feedstock, but only because the two processes and two feedstocks used by the manufacturer were not significantly different from each other. It is concluded that process and feedstock can have a significant effect on emissions of individual compounds, but it is not possible from this study to make specific recommendations regarding how process or feedstock might be modified to produce lower-emitting toners for a given copier.
Abstract
Water-based cleaners applied with hand-pump sprayers are used extensively in residences and by janitorial staffs in large buildings. Users of cleaners may be exposed to volatile organic compounds (VOCs) that evaporate from surfaces being cleaned and by inhalation of liquid droplets in the air following application. Tests have been performed in controlled environment test rooms to measure gas-phase and particulate emissions during use of a water-based cleaner with a hand-pump sprayer.
Tests were performed in the bathroom of a test house and in an 18 m3 controlled-environment test room. The water-based cleaner, which contained 50 mg/g of 2-butoxyethanol (butyl cellosolve), was applied to realistic surfaces (counter tops, glass, mirrors) with the manufacturer's hand-pump spray. During application, air samples were collected on Tenax for analysis of 2-butoxyethanol by gas chromatography. Concentrations of droplets were measured continuously with aerodynamic particle sizers.
The average concentration of 2-butoxyethanol measured by collection on Tenax for a 10-minute period in a closed bathroom during, and following, application of 96 g of a 50:1 (v/v) dilution of the cleaner was 760 µg/m3 (0.16 ppm). This was well below the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value of 25 ppm. The mean particle droplet size during the application period was in the range of 1 to 2 µm. Particle concentrations increased during application with the sprayer, but dropped quickly. Results will be presented for 2-butoxyethanol concentrations and particle concentrations and size distributions during, and following, different application scenarios.
Abstract
A vital operating compound in many electronic products today is the printed circuit board. In particular, printed circuit boards can be found in office products such as personal computers (PCs), telephone, fax machines, and photocopiers. Many of these products are placed in environments where indoor air quality and human exposure to volatile chemicals are major concerns. Volatile chemicals emitted from office equipment during on-time use have been attributed to adverse health effects in humans.
Offgassing from office products is most prominent during the initial break-in period when electrical heating occurs. This is especially true in the case of PC monitors, the internal operating temperatures of which can range from 60 to 70 °C at full power.
In this evaluation, printed circuit board laminates, without circuitry, commonly found in PC monitors were tested to determine if an alternative laminate would be less emitting than conventional laminates. Test results qualitatively showed that the alternative, a glass/lignin-containing epoxy resin laminate, emits fewer volatile compounds than paper/phenolic resin-based laminates. The data also suggest that, if these laminates were used as a replacement for paper/phenol circuit board laminates in PC monitors, reductions in emissions from PC monitors could be achieved in indoor environments where they are used.
Abstract
Because no standard test method exists to measure emissions from office equipment (e.g., ozone, volatile organic compounds, aldehydes/ketones, inorganic gases, and particles), it is difficult to compare data from different studies. Thus, the focus of this cooperative agreement was the development and evaluation of a large chamber test method to better understand emissions from office equipment and to develop lower emitting machines. Challenges and complications encountered in developing and implementing the method include: heat generation which can cause large increases in chamber temperature; finite paper supplies for photocopiers which limit test duration; toner off-gassing between tests or toner carryover if different types of toner are tested; varying power requirements that may require changes in chamber electrical supply; and remote starting of the machines which is necessary to maintain chamber integrity.
The test method was evaluated in two phases. Phase I was a single laboratory evaluation of the method at RTI using four mid-range dry-process photocopiers. Phase I results indicated that the test method provided acceptable performance for characterizing emissions, adequately identified differences in emissions between machines both in compounds emitted and their emission rates, and was capable of measuring both intra- and inter-machine variability in emissions. For Phase I, the compounds with the highest emission rates from the four different machines tested were; ethylbenzene (28,000 µg/hour), m,p-xylenes (29,000 µg/hour), o-xylene (17,000 µg/hour), 2-ethyl-l-hexanol (14,000 µg/hour), and styrene (12,000 µg/hour). Although many of the same compounds were detected in emissions from each of the four photocopiers, the relative contribution of individual compounds varies considerably between machines, with differences greater than an order of magnitude for some compounds. The toners appear to be the primary source of organic emissions from the photocopiers.
Because all chambers may not produce similar results, Phase II was a four-laboratory round-robin evaluation of the method. A single dry-process photocopier was shipped to each of the four laboratories along with supplies (i.e., toner and paper). Phase II results demonstrate that the method was used successfully in the different chambers to measure emissions and that differences in chamber design and construction appeared to have had minimal effect.
Abstract
The objective of this research was to investigate pollution prevention options to reduce indoor emissions from a type of finished engineered wood. Emissions were screened from four types of finished engineered wood: oak-veneered particleboard coated and cured with a heat curable acid catalyzed alkyd-urea sealer and topcoat (PBVST); oak-veneered hardboard coated and cured with a stain, and a heat curable acid catalyzed alkyd-urea sealer and topcoat (HBVSST); particleboard overlaid with vinyl (PBVY); and particle board overlaid with melamine (PBM). The PBVST and HBVSST had substantially higher initial emission factors of summed volatile organic compounds (VOCs) relative to those for PBVY and PBM. The PBVST and HBVSST also had higher decay emission factors of formaldehyde relative to the initial emission factors of formaldehyde for PBVY and PBM.
The acid catalyzed alkyd-urea coatings and particleboard were identified as sources of VOCs from PBVST. A coatings study was conducted to evaluate emissions and performance properties of potentially low-emitting substitutes for the acid catalyzed alkyd-urea coatings. Within the scope of the emissions and performance tests of the study, three types of coatings were found to have significantly lower emission factors of summed VOCs and formaldehyde relative to those for the heat curable acid catalyzed alkyd-urea coatings, these included a two component waterborne polyurethane; a UV curable acrylate; and a UV and heat curable multi-functional acrylate-free emulsion. These coatings also had comparable performance characteristics to the heat curable acid catalyzed alkyd-urea coatings. All three wood coatings are currently available in the market place.
A fiber study was conducted to evaluate emissions of potentially low-emitting engineered fiber panels. Three types of engineered fiber panels were identified as having significantly lower emission factors of summed VOCs and formaldehyde relative to those for particleboard; these included medium density fiberboard made with methylene diisocynate resin (MD); a wheatboard panel made with MDI resin; and a panel made from recycled corrugated cardboard. All three fiber panels are in the market place and are used to construct a wide variety of interior products.
Abstract
Conversion varnishes are two-component, acid-catalyzed varnishes that are commonly used to finish cabinets. They are valued for their water- and stain-resistance, as well as their appearance. They have been found, however, to contribute to indoor emissions of organic compounds. For this project, three commercially available conversion varnish systems were selected. An EPA Method 24 analysis was performed to determine total volatile content, and a sodium sulfite titration method was used to determine uncombined (free) formaldehyde content of the varnish components. The resin component was also analyzed by gas chromatography/mass spectroscopy (GC/MS) (EPA Method 311 with an MS detector) to identify individual organic compounds. Dynamic small chamber tests were then performed to identify and quantify emissions following application to coupons of typical kitchen cabinet wood substrates, during both curing and ageing. Because conversion varnishes cure by chemical reaction, the compounds emitted during curing and ageing are not necessarily the same as those in the formulation. Results of small chamber tests showed that the amount of formaldehyde emitted from these coatings was 2.3 to 8.1 times the amount of free formaldehyde applied in the coatings. A long-term test showed a formaldehyde emission rate of 0.17 mg/m2/h after 115 days.