Three dimensional printers, capable of building small models, prototypes, and one-off plastic parts are still mostly found in the world of technology geeks but rapidly reducing prices are bringing these devices within the reach of regular households and offices. It is therefore timely that a group of scientists led by Dr. Brent Stephens of the Armour College of Engineering at the Illinois Institute of Technology, has looked at air emissions from these printers. According to a paper published in the peer-reviewed journal Atmospheric Environment, at least some of these printers emit ultrafine particles (UFPs) at concentrations that may be hazardous in confined spaces.

3D printers work by heating a plastic material and spraying it on to a platform in a manner somewhat similar to that of an inkjet printer, except that instead of applying one layer, as from an inkjet printer, the 3D printer applies layer upon layer, slowly, sometimes quickly, building up a three dimensional plastic model of whatever item it is programmed by a desktop computer to print. All kinds of software is now available to enable these devices to print such things as gear wheels, architectural models, parts for household and commercial appliances, and so on. Currently most printers are limited to smaller parts, up to about 20 cm in each dimension, but larger 3D printers will be available before too long.

Currently these printers generally use plastic resins from the families ABS (acrylonitrile butadiene styrene) and PLA (polylactic acid), heating the resins sufficiently that they can be sprayed from very fine nozzles. It appears to be both the heating, which causes slight decomposition of the plastic, and the spraying that give rise to the indoor air pollution concerns. UFPs are known to deposit in lungs and can lead to stroke, asthma,  and death. The level of UFPs emitted from 3D printers was found to be quite high. The scientists note that this first research is not conclusive regarding health risks from 3D printers but the research does indicate possible problems and more research is needed. In the meantime care should be taken when using 3D printers in indoor environments without adequate particle filtration and ventilation.

An abstract and the complete paper are available at http://www.sciencedirect.com/science/article/pii/S1352231013005086