So I've spent the morning reading the literature on thermoplastics and ultrafine particle (UFP) emissions and concentrations from this manuscript (
http://www.sciencedirect.com/science/ar ... 1013005086) and from my PubMed searches.
As a perspective, my "day job" is 50 percent clinical cardiology and 50% basic science research at the University of Nebraska Medical Center in Omaha, Nebraska. My research studies evaluate the impact of inflammation, oxidation and free radical formation due to diet, exercise and medical problem such as high blood pressure and high cholesterol. We study this with a focus on tissue injury and cardiovascular diseases such as heart failure and atherosclerosis. So when my friend asked me the question about the cancer and health risk of the "plastic smell" I was a bit mortified I had not though much about it but.......... I'm glad he asked.
In medicine we worry about disease as a consequence of exposure, the duration of exposure and the toxicity of the agent/substance to which you are being exposed. Thus, while I agree that the level of UFP generated from a single printer is less than the particles produced from a cooked stovetop meal (linked article above), and immediate toxicity requires a much higher level of exposure, I do worry about the duration of exposure. We all know our prints are hours or days in length vs. we cook for 20-40 minutes a day (since Jan of this year I have printed over 700 hours). As well, I worry about the toxicities of the substances present in plastic (carbon monoxide, hydrogen cyanide and volatile organics) which have been shown to cause health problems when exposed to higher than typical daily levels of the toxic substance (i.e. they are dose dependent). In that regard less exposure is "likely better." Of interest, I have yet to set off my carbon monoxide detector in my house to date which would indicate an immediate risk of asphyxiation. However, I have not placed the detector in the room where my printer is set up. I doubt it will go off since 3D-Printing is not dropping us like flies. I will test it out of curiosity.
My analogy to this is hypertension. As single day of high blood pressure poses no immediate risk or problems unless it is uber high (200 mmHg) which would be akin to the carbon monoxide detector going off. However, years and years of high blood pressure is clearly associated with heart attacks and stroke. Every increase in blood pressure by 5 mmHg over the baseline cutoffs, is associated with a statistically increased risk of a heart attack or a stroke with decades of exposure.
Thus, everything I know tells me to limit the exposure and ventilate well. A HEPA filter is a good step in that direction, however a HEPA filter is certified to remove 97% of particles which are 3 micrometers in size (300 nanometers). The PLA and ABS particles from a 3D printer are approximately 11.5-116 nanometers in size. Thus, it will not remove the particles.
I know this is not well understood and there is a debate on the impact with some proposing that the risk is similar to smoking tobacco. It is crazy to not print, however, the doctor part of tells me to be more careful. Of note, asthma in my house has been much worse this spring. Cause and effect..... I'm not sure....
I will not stop printing, but I will build a ventilation system for my enclosure and move the printer to an exterior wall. By moving it to an exterior wall, I think I will use a one inch flex tubing (or something similar) attached to the plexiglass with a variable speed fan to directly vent the chamber "gasses." I still should be able to keep the chamber warm, while venting the chamber. I will post this here and on my build thread.
Household air quality is important. Its an easy and cheep fix add on to the printer (another hole in the house)!
Thank you,
Dan
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Daniel R. Anderson, MD, PhD