Laser Printer Emissions Study Leaves Health Questions Hanging

A new study on particle emissions from laser printers has been published, but it does little to clarify the health effects of working in an office with a laser printer.

In August 2007, a study published in the American Chemical Society's Environmental Science & Technology journal classified 17 out of 62 printers as "high particle emitters" because of the amount of ultrafine toner particles they put into the air.

The study likened the particle output to secondhand smoke in terms of the size and distribution of the particles, a comparison that elicited worldwide interest in the possible health impact of working in areas with laser printers.

Hewlett-Packard, one of the makers of printers tested, responded immediately by challenging the study. "There are no indications that ultrafine particle emissions from laser printing systems are associated with special health risks," it said in a statement. "Currently, the nature and chemical composition of such particles -- whether from a laser printer or from a toaster -- cannot be accurately characterized by analytical technology."

The new study, led by Lidia Morawska, a professor at Queensland University of Technology in Brisbane, Australia, and the author of the initial study, aims to address that claim by providing an analysis of the characteristics of particles emitted from laser printers and the mechanisms by which they are formed.

It states that "several studies have reported that laser printers can be significant sources of ultrafine particles -- a complex pollutant whose toxicological effects have been recently acknowledged by the World Health Organization." And it goes on to list a variety of chemicals detected during testing: hexane, toluene, ethylbenzene, styrene, and pentadecane, to name a few.

But it provides no guidance as to how office workers should view the research. It aims solely to answer what the particles are made of, how they're formed, and why some printers produce more of them than others.

Asked to explain the extent to which laser printer particles can be compared to cigarette smoke in terms of health impact, Morawska pointed to list of frequently asked questions posted on the Queensland University Web site.

The University's Web site says that the particles emitted by printers are similar in size to those from cigarette smoke, vehicle exhaust, and toasters. It reiterates that toxicological studies point to a health risk from the inhalation of ultrafine particles and that the indoor concentration of particles emitted from laser printers can reach similar levels to the indoor concentration of second-hand cigarette smoke or to the outdoor concentration of particles at a busy road.

"This is, however, where the comparison ends," the Web site states. "Cigarette smoke and likewise vehicle-emitted particles contain, in the first instance, primary particles comprised of solid carbonaceous material, which are not volatile. Also the chemistry of particles originated from these different sources is different to the printer particles."

In a 2004 report published by the Australian Department of the Environment and Heritage, Morawska and her co-authors were a bit more direct when it comes to tiny particles in general. "Both fine and ultrafine particles appear to affect health outcomes such as mortality and respiratory and cardiovascular morbidity and appear to do so independently of each other," that report states. "However, the database at present is too limited (both in numbers of studies and numbers of subjects) and geographically restricted, to allow clear conclusions on the mode of action or generalization to other settings."

In an e-mailed statement, the EPA said, "Many common products used in offices, like solvents, adhesives, cleaners, and pesticides can give off pollutants and odors, as can office equipment such as copiers, printers, and fax machines. If any of these items are used in the office environment, adequate and sometimes separate ventilation should be provided. If your organization engages in activities that may generate pollutants, such as photographic or printing processes, exhaust ventilation will be especially important.

"Pollutants and odors (which may or may not indicate a health concern) generated in your space may not only bother those in the immediate area, but may enter the building ventilation system and cause problems for other tenants in other parts of the building."

The EPA maintains a Web site at AirNow.gov that provides air-quality data and a color-coded air quality rating scheme similar to the Homeland Security Advisory System.

The World Health Organization in 2005 said that there's not yet enough evidence to assess the impact of ultrafine particles on human health. "While there is considerable toxicological evidence of potential detrimental effects of UF particles on human health, the existing body of epidemiological evidence is insufficient to reach a conclusion on the exposure-response relationship of UF particles," WHO's 2005 air-quality guidelines for particulate matter states. "Therefore no recommendations can be provided as to guideline concentrations of UF particles at this point in time."

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