Printer particle emissions add up
New findings underscore the effects of indoor air on human health
When researchers in Australia discovered that particulate matter levels were five times higher during the workday inside a nonsmoking office building than outside near a freeway, they looked for indoor culprits. After testing more than 50 printers throughout the building, they found that particle emissions varied depending on the type and age of the printer. In one case, standing near a working printer was much like standing next to a cigarette smoker. The results are described in new research published in ES&T (DOI: 10.1021/es063049z).
Lidia Morawska of the Queensland University of Technology (Australia) and colleagues monitored printers of numerous makes and models with printer toner cartridges at various stages of use—from new to depleted. They also tested several representative printers in an experimental chamber to carefully track the concentrations and distributions of different size particles from high to low emitters.
Only a handful of studies on modern printers exist in the literature, says Morawska. Further research should include performance tests of multiple printers of the same model and make. Her team intends to follow up with more studies that analyze the chemistry of the particles, which will also have implications for health impacts.
Ten years ago, the U.S. EPA evaluated printers and photocopiers, but these data are now "interesting historical information," comments Charles Weschler of the University of Medicine and Dentistry of New Jersey. Printers have changed a lot since then: most have shifted to ink jets and other technology, and dramatic improvements have changed cartridges and even "the nature of toner itself," Weschler says. These new data are only the first steps in getting modern assessments of exposure to printer particulate matter, he says.
Weschler notes that the team found a wide range of emissions levels. "Emissions may be highest with a brand-new cartridge, just opened," he speculates, when the solvent is highest and the toner is "ripe". But even with one printer, such as the one the team observed that was particularly offensive, "if we were to look at 10,000 printers, which isn't realistic, how common is that one bad apple?" Weschler asks. Perhaps not very, he suggests, considering that companies themselves conduct testing to meet certain criteria (for example, Germany's Blue Angel certification).
Erik Uhde of the Fraunhofer Institute for Wood Research (Wilhelm Klauditz Institute [Germany]) says that printers even within a manufacturer's series can vary, depending on where the parts were purchased, among other factors. "The sources of particulate matter in the printer are not completely clear," he says, and toner may not have as much impact as suspected.
Nevertheless, the research underscores the importance of printer emissions when considering human exposure to particulate matter. "Most of your time is [spent] indoors at the office or indoors at home," Weschler says, so "most of your exposure is indoors, either to chemicals that originated indoors or that are brought in by ventilation."
