Health Hazard for Household FDM 3D Printer

_{Photo Source: https://pixabay.com/en/printer-3d-pressure-3d-printing-1455169/}

Nowadays, FDM 3D Printers are possible to be one of the most common 3D printers in household usage and personal projects. However, the health impacts of these 3D printers are usually ignored by us. Accumulating studies and evidence shows that FDM 3D printers will emit harmful particles to the air, threatening the health of our families and children.
There are 3 main types of particles that have a relatively high emission rate from FDM 3D printers and having the greatest concern from researchers, they are Volatile organic compounds (VOCs), ultrafine particles (UFPs) and Fine particles (mainly PM 2.5). In the following, we will explain the health impact from these particles separately.

What is FDM 3D Printer?

The most common 3D printer currently is probably the Fused Deposition Modeling (FDM) 3D printer. Each type of 3D printer has different principle of operation; therefore, if you are not familiar with 3D printers, you should be careful and not to mix FDM up with powder 3D printer or resin 3D printer.
So, how is Fused Deposition Modeling print object? First a thermoplastic filament is fed through a heated moving nozzle. The filament is than heated to semi-liquid state and deposited onto platform by an extrusion nozzle. During extrusion, either the nozzle or the platform is moved on the x-y plan. After each layer is completely deposited, either the nozzle is moved upward or the bed is moved downward to start the next layer. Supporting will be added for overhang objects. The supporting materials will be either the same material with a removable structure or a water-soluble material, which can be removed by placing in the water.

Health Impact of different 3D Printer Emission

Health Impact of VOC to Human

Volatile organic compounds (VOCs) are organic chemicals that have a high vapor pressure which results from a low boiling point at ordinary room temperature. This boiling point causes lots of molecules to evaporate or sublimate from the liquid or solid form of the compound. After that, it enters the surrounding air as known as volatility. For instance, formaldehyde evaporates from paint and releases from materials like quartz and its boiling point is only –19 °C (–2 °F).
VOCs are not only dangerous to human health but also harmful to the environment. Harmful VOCs typically are not acutely toxic depending on concentration, but have compounding long-term health effects.
The VOCs has the following health effect on human, [1]

1. Respiratory, allergic, or immune effects in factory humans
2. Some VOCs elements such as styrene and limonene can react with nitrogen oxides or with ozone to produce new oxidation products and secondary aerosols that can initiate sensory irritation symptoms.
3. Health effects include eye, nose, and throat irritation; headaches, loss of coordination, nausea; and damage to the liver, kidney, and central nervous system.
4. Key signs or symptoms associated with exposure to VOCs include conjunctival irritation, nose and throat discomfort, headache, allergic skin reaction, dyspnea, declines in serum cholinesterase levels, nausea, vomiting, nose bleeding, fatigue, dizziness.

Health Impact of UFPs to Humans

Ultrafine particles (UFPs) are particulate matter of nanoscale size. (Less than 0.1 μm or 100 nm in diameter).
There are two main categorize types of UFPs which are carbon-based or metallic. UFPs are both manufactured and naturally occurring and are the main constituent of airborne particulate matter. Due to their numerous quantity and ability to penetrate deep within the lung, it is a major concern for respiratory exposure and health.
The UFPs has the following health effect on humans, [2]

1. Ultrafine particles are deposited in the lungs, where they have the ability to penetrate tissue and undergo interstitialization or to be absorbed directly into the bloodstream— and therefore are not easily removed from the body and may have immediate effect.
2. Exposure to UFPs, even if components are not very toxic, may cause oxidative stress, inflammatory mediator release, and could induce heart disease, lung disease
3. UFP is associated with an increase in blood pressure
4. Causing permanent DNA mutations, heart attacks and premature death.

Health Impact of Fine Particle to Humans

Fine particles are airborne particles are smaller than coarse particles and has an aerodynamic diameter of 2.5 μm or less (PM2.5). They are largely formed from gases.
The Fine Particles have the following health effect on humans, [3]

1. Increase mortality of chronic disease/ Reduced Life expectancy
2. Increase clinical visits/ hospitalization rate / Mortality
3. Systemic inflammation/oxidative stress
4. Respiratory inflammation/oxidative stress
5. Reduced lung function
6. Impaired vascular vasomotor function/Fibrinolysis
7. Increased thromogenicity/Platelet activation
8. Increased arterial tone/Arterial stiffness
9. Increased blood pressure
10. Reduced heart rate variability
11. Increased myocardial ischemia

Comparison of Health Impact of the Three Particles to Humans

The figure below compares the health impact of the three scales of fine particles.

_{Figure :Respiratory Deposition Curve [4]}

_{Alveolus line stands for very small air bags in the lungs with thin walls that allow oxygen to enter the blood. (Affected part - Lung)
TB (Tracheal Bronchus) line stands for a bronchial anomaly originating from the trachea or either main bronchus and directed to the upper lobe territory. (Affected part - Lung)
Head Airways line stands for head blood vessels. (Affected part – Head vessels)
By adding the above three lines, it can be noted that total fraction of UFPs is most toxic particle among them especially affecting the lung. [5]}

Other Hazard from FDM 3D Printer

After doing some case studies, we also found some other safety hazard beside from the harmful emission. In a case, a 17-years old boy was died in an explosion related to 3D printers. [6] Adhesion of the printing object to the built plate is one of the challenges of FDM 3D printing. One common method is to use hairspray to act as an adhesive. In this case, the hairspray is ignited by a spark, causing an explosion to kill the boy. Although the actual way of ignition is unclear, the heat source from the 3D printer could be one of the possible reasons. Therefore, if hairspray is used as adhesive, similar accident could happen if proper safety measure is not taken.

What should we do?

I understand that it is unavoidable to use FDM 3D printers in this age. Therefore, if you are personal users or parents, I suggest you to focus on using protective measure like air filter to remove the health hazard in the environment. However, there a lot of problems in current household air filter. If anyone is interested to know more about how to select air filter, please leave me a comment, perhaps I can create a new post to discuss if needed.

Reference

[1]Wikipedia, "Volatile organic compound," Wikipedia, 10 October 2017. [Online]. Available: https://en.wikipedia.org/wiki/Volatile_organic_compound. [Accessed 1 December 2017].
[2]Wikipedia, "Ultrafine particle," Wikipedia, 6 November 2017. [Online]. Available: https://en.wikipedia.org/wiki/Ultrafine_particle. [Accessed 1 December 2017].
[3]Y. Q. HAN and T. ZHU, "Health effects of Fine Particles (PM_2.5) in ambient air".
[4]Oberdörster, "Inhal Toxicol," 1995.
[5]Johnston, "Toxicol Applied Pharmacol," 2000.
[6]H. R. Mendoza, "3d Print.com," 3DPrint.com, 6 11 2016. [Online]. Available: https://3dprint.com/154484/deadly-3d-printer-accident/.