Health problems have been repeatedly reported in connection with laser printers for several years. Measurements show that many printer models emit various amounts of volatile organic compounds and ultrafine particles (smaller than 0.1 µm)
Since it is difficult to prove a causal relationship between the variable office conditions, an experimental verification under controlled conditions seemed to be reasonable. Therefore, the BAM Federal Institute for Materials Research and Testing in Berlin and the Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine at the Munich Center of Health Sciences (MC-Health) of the Ludwig-Maximilians-University (LMU), performed studies on volunteers in a research project sponsored by the German Social Accident Insurance (DGUV). 23 healthy test control individuals, 14 individuals with mild asthma and 15 individuals who reported discomfort when dealing with laser printers took part in the study.
All subjects were exposed to both very high and very low concentrations of ultrafine particles under standardised conditions in a special room for 75 minutes each. The two exposures were performed in a random pattern on two different days. The probands did not know which exposure occurred on which day. The laser printers used were selected based on their particle emission rates as well as chemical composition and size distribution of particles created, from a pool of devices that was characterised by BAM with respect to their emission behaviour. Prior to the studies, the exposure conditions were extensively tested in a known space (test chamber) and standardised. Important parameters were continuously recorded during the exposure tests in order to ensure comparability. The high concentration level (100 000 particles/cm³) was created by two laser printers with high ultrafine particle emission and represented an extreme ("worst case") office situation. The two laser printers with a very low particle emission rate gave no measurable contribution to the room’s background level (about 3000 particles/cm³).
Possible effects on the volunteers were recorded using functional, biochemical, psychological and psychometric methods. The methods were chosen so that they covered as many of the complaints as possible that are typically reported by affected persons and can be tested by quantities that can be objectivised. The measurements were made before and during a period of approximately two hours duration after the exposures.
Since the study reflects a short-term scenario, only limited conclusions are possible with long-term exposures. Likewise, no statement can be made about whether or not body organs are affected that were not included in the study, or delayed effects occur which are only apparent after a number of days.
The results of this study are not alarming from a clinical perspective. They do not suggest that high particle loads from laser printer emissions cause a disease process in the way that corresponds to the spectrum of reported diseases attributed to laser printers. Notwithstanding, exposure reduction and prevention measures appear reasonable to reduce harassment by the printer emissions as much as possible.