3D Printing Air Quality Roundup for 2024

One of the goals of 4D Filtration is to make scientific research more accessible, and this page is to serve as a summary of air quality works to date. Every year dozens of new papers on 3D printing volatile organic compounds (VOCs), Ultrafine Particles (UFPs), and even innovations within filtration are submitted to the scientific community and general public.

The data from the works presented here add to a growing foundation of understanding 3D printing safety. Many of these studies are conducted in a laboratory environment under a wide variety of operating conditions, which is why many of the values presented are averaged or provide a range. We will make and present assumptions to simplify math and increase relevancy.

If you find a new article that we have not listed yet, feel free to contact us and we will add relevant data. If you are a consumer concerned about 3D printing air quality safety in your home, one of the best things you can do is move the 3D printer into a garage or workshop. This nearly eliminates the impact a 3D printer has on long-term indoor air quality.

Overview - Important Takeaways

• Consumer 3D printers should be placed in a garage or workshop to minimize long-term health risks.
• The use of cartridge respirators are encouraged, especially when cleaning resin prints. While typically overkill for consumers, a supplied air respirator provides a higher level of protection. These are useful if you want to be in proximity to contaminants for prolonged durations.
• Resin printers inside a home must be vented outdoors. FDM printers should use filtration when ventilation is not possible.
• Both FDM and resin 3D printers generate billions of Ultrafine Particles (UFPs) per minute that can deposit in the lungs and enter the bloodstream.
  
  The use of filters is recommended inside the home to capture UFPs, and they are encouraged when venting to prevent UFPs from entering the environment, specifically nanoplastics that can enter food and water supply chains.
• MERV 13-16 filters capture 60-95% of UFPs per pass, which is ideal for recirculating air filtration. Using a 4-inch deep panel or a bag filter on a box fan is an affordable solution to capture particulates within a room.
  
  HEPA 13-14 filters capture 99.95-99.995% of UFPs per pass, which is ideal for extraction from an enclosure.^22,23
• Cooking food on a stovetop can generate UFPs at a rate similar to that of a 3D printer. However, you can reduce this exposure by using a ventilation hood, adding salt to meat, choosing cooking methods such as boiling instead of frying, and having an air cleaner in the kitchen.^5,6
• Both FDM and resin printers generate dozens of VOCs in detectable quantities. A few of the VOCs exceed US and EU safety limits, and we still need more data on this topic, especially for resin. VOC concentration will increase as printers are added and the volume in a room shrinks (closet vs large garage).
• Most individual VOCs from 3D printers will present as odorless. The repulsive smell from resin printers can come from individual VOCs such as Methacrylic Acid. If the concentration of this specific VOC is decreased by 15% in an average sized room (30 m), then it can become odorless. This is an example of how removing the odor does not remove the VOCs.
• Activated carbon beds with a thickness of 1-2 inches will only capture 40-60% of VOCs per pass.¹
• Activated carbon has the ability to adsorb and retain 25-30% of its own weight in isopropyl alcohol (IPA), while other VOCs such as Formaldehyde may only be retained at 2%.^2,3,4
• With the assumptions of 10% TVOC retention by weight (g/g) at 60% humidity, a TVOC emission rate of 10 mg/hr, and a factor of safety of 3 to 5, 250 g of activated carbon in a sealed recirculating system will become saturated after 500-800 FDM printing hours. This is 20-30 days of 24/7 printing,  and 6 hours of printing per day will saturate the carbon within 3-4 months. The lifespan of carbon will be reduced with increasing humidity, additional printers, engineering filament, and higher nozzle temperatures.

Overview - Examples & Guidance

• To maximize safety, all 3D printers should be placed outside the home in a garage or workshop when available. The use of a shed or enclosure on a patio or balcony is feasible but less common.
• PLA garage or workshop - Ready to print; encouraged to capture UFPs.
• ABS, HIPS, PC, etc garage or workshop - Ready to print; encouraged to vent and capture UFPs.
• Resin garage or workshop - Ready to print; recommended to vent.
• PLA indoors - Keep out of bedrooms and use a small air cleaner to capture UFPs.
• ABS, HIPS, PC, etc indoors - Isolate the FDM printer in a separate room and vent out a window if possible; otherwise, use an air cleaner to capture UFPs and VOCs.
• Resin indoors - Isolate the resin printer in a separate room and vent out a window. Filtration should only be used as mitigation.

How does 3D printing affect air quality?

All 3D printers, including FDM and Resin, release Ultrafine Particles (UFPs) and Volatile Organic Compounds (VOCs)

• Particulates are tiny, solid particles composed of plastic, elemental materials, or other debris. When you breathe, these particles can enter pass your nose and enter your lungs. Although we all encounter particulates daily, some of them are larger and are blocked by our body's natural defense mechanisms.
  
  UFPs are the smallest of particulates and when breathed in, they settle in the lungs and have the potential to enter the bloodstream or harm the lungs directly. Inhaling UFPs places additional stress on the body, elevates the risk of heart disease and lung ailments, and increases systolic blood pressure.^7,8
• VOCs are gaseous compounds emitted by various natural and synthetic materials in our surroundings. A few common VOC sources are perfumes, candles, paint, the distinctive smell of new cars, and even methane from cow flatulence.
  
  Many of these VOCs are safe in small amounts, but some have been identified as carcinogenic. Harmful VOCs can lead to a diminished quality of life, exacerbate asthma, trigger headaches, induce nausea, cause allergic skin reactions, and harm vital organs. What makes VOCs particularly concerning is their potential to harm children, pets, and loved ones without our awareness.

Who should be worried about UFPs and VOCs from 3D printers?

Pregnant women, children, elderly, and the immunologically compromised are most vulnerable

• A developing fetus is highly sensitive to external chemicals and atomized particles. The emissions generated by 3D printers can potentially harm fetal development. In particular, the chemicals found in UV polymerization resin have been linked to developmental abnormalities.^9,10,11,12
• Children are more likely to develop asthma if the mothers were exposed to higher levels of UFPs during pregnancy.²⁴
• The UFPs emitted by 3D printers add to the existing microplastic pollution in our bodies. To reduce exposure to microplastics, it's advisable to ventilate or filter the emissions from 3D printers, use filtered water for drinking, heat food in ceramic or glass containers, and avoid disposable plastic products.¹³
• When a 3D printer is situated in a garage or workshop, the long-term exposure risk is significantly diminished. Although it's still beneficial to ventilate or filter the emissions, the immediate need to do so is reduced in such a setup.
• If you have a 3D printer in your home or office, it's advisable to filter or ventilate the emissions.
• To minimize the short-term risk associated with 3D printer emissions, you can use a cartridge respirator or a supplied air respirator.

What are the impacts of UFPs from 3D printers?

Billions of Ultrafine Particles (UFPs) are created every minute with both FDM and resin printers

• UFPs are pollution particles with a diameter of less than 100 nanometers (nm). To put this in perspective, a water molecule is 0.27 nm, DNA is 2 nm, viruses are around 100 nm in size, and a typical piece of paper is about 100,000 nm thick.
• PM2.5 particles have a size of 2,500 nanometers (2.5 micrometers or μm) or smaller. The majority of research and public guidance focuses on particles ranging from 100 to 10,000 nm (0.1 to 10 μm) in diameter.
• When UFPs are inhaled, they deposit in the lungs where they can enter the bloodstream and be distributed throughout the body. The kidneys and intestines help filter UFPs out of the body.²⁴
• Inhaling UFPs increases stress on your body, is linked to increased blood pressure, and can cause asthma.
  
  Long-term exposure to UFPs include increased risks of heart disease, lung disease, liver cancer, brain tumors, and strokes.^7,8,24

How do 3D printers compare to other air pollution sources?

3D printers, cooking, and candles are some of the primary UFP sources in the home

FDM printers generate 8.8×10⁷ - 2.8×10¹² UFPs/min and 0.42-4 mg of TVOC/hr

Resin printers generate 1.3×10⁸ - 4.0×10¹⁰ UFPs/min and 5-88 mg of TVOC/hr

The significant variation in the reported values is a result of different sampling methods, materials used, and testing conditions. This underscores the importance of implementing standardized testing procedures and conducting further assessments. It's worth noting that the range of Total Volatile Organic Compounds (TVOC) for resin printers includes data from post-processing stages.^{14,15,16,17,18,19}

• New furniture immediately after production has the potential to off-gas VOCs at the same rate (mg/hr) as a 3D printer, but this rate significantly decreases in the weeks after production. Since most furniture spends months transiting and in storage, the risk with furniture compared to a 3D printer is minimal.²⁰
• Laser printers exclusively produce Ultrafine Particles (UFPs) with the most common diameter being 34 nm. The UFP emission rate ranges from 3.4×10⁸ - 1.6×10¹² per minute, which is similar to what a 3D printer produces per minute. The Brother MFC-L2700DW releases 1.35×10¹⁰ particles per minute and can print 26 pages per minute, which can be equated to each page releasing 5.2×10⁸ UFPs. Since laser printers are in use for minutes while 3D printers run for hours, laser printers as a source of UFPs is minimal compared to 3D printers.²¹
• Scented candles were found to have VOC emission rates up to 1,000 times higher than unscented candles, of which could include Formaldehyde. Another study conducted on several dozen types of candles found an average UFP emission rate of 4.7×10¹² per minute, which is slightly higher than a 3D printer. While occasional candle burning can be pleasing, habitual use of scented candles should be discouraged. If you know someone that insists on using candles daily, consider gifting an air cleaner to reduce UFPs that increase health risks.^26,27,28
• Cooking ground beef in a non-stick pan on an electric burner without ventilation produced 9.4×10¹² UFPs per minute, which is slightly higher than a 3D printer. Interestingly, the emission rate decreased to 5.7×10¹¹ UFPs/min when the ground beef was salted. Even with active ventilation over a stovetop, you would be in close proximity to this UFP source for a prolonged period of time.⁵
• Another study found that turning on a gas stove generated 2.6×10¹¹ UFPs per minute. This increased to 5.8×10¹² UFPs/min when heating an empty pan. Pan frying tofu generated 1.0×10¹³ UFPs/min, whereas boiling tofu was only 5.3×10¹¹ UFPs/min.⁶

What are some of the VOCs from 3D printing?

VOCs released during preparation, printing, post-processing, and in smaller amounts months afterwards

• VOCs like Alpha-pinene, Lactide, Limonene, and Propylene Glycol are well-studied chemicals that are safer for us to be exposed to, which is why they are common in foods, fragrances, and everyday goods.
• Hazardous VOCs like Dioxane, Formaldehyde, and Styrene have been linked to an increased risk of cancer. Although products like Styrofoam remain stable under ideal conditions, any exposure to heat can cause Styrene to leach into liquids and foods, and burning Styrofoam can release Styrene gas.
• 3D printing resin is well-known for its potential to sensitize the skin. This sensitivity is attributed to the chemicals used as ingredients, including Ethyl Methacrylate, Hydroxypropyl Methacrylate, Isobornyl Acrylate, Methyl Methacrylate, and various photoinitiators.

3D Printing VOCs Overview

How much of these VOCs are actually being released from 3D printers?

These are the same VOCs with their potential concentrations and safety limits

• To help you interpret the table we will start with an example. Assuming no ventilation, filtration, or mixing with air external to the room that the printer is in, we can estimate concentrations of a VOC given experimental emission rates.
  
  For a 6 hour resin printing session with 15 minutes of cleaning and 30 minutes of curing, the Formaldehyde emitted over the session is (6 hours × 0.006 mg/hr) + (0.25 hours × 0.012 mg/hr) + (0.5 hours × 0.012 mg/hr) = 0.045 mg.
  
  The average US room size is 11 x 12 x 8 ft which is 1,056 ft³ or 30 m³. The average US garage size is 24 x 24 x 8 ft which is 4,608 ft³ or ≈130 m³. A smaller room or closet may only be 250 ft³ or 7 m³. The Formaldehyde concentration (mg/m³) for a garage would be 0.00035 mg/m³, room 0.0015 mg/m³, and closet 0.006 mg/m³.
  
  These concentrations begin to approach the minimal risk level (MRL) for Formaldehyde of 0.01 mg/m³ (chronic >365 days) and 0.05 mg/m³ (acute 1-14 days). An analysis of these results can conclude that Formaldehyde alone is not an immediate risk, but exposure in a small space over years can have health consequences. However, safety can be vastly improved with ventilation and filtration.
  
  The active ventilation that is recommended for resin printers will nearly eliminate the concentration from the workspace. Filtration of Formaldehyde by non-specialized activated carbon is poor compared to other VOCs, and increasing humidity will drastically decrease the capture efficiency and holding capacity.
• FDM and resin 3D printers do not release VOCs in short-term fatal amounts, but rather in a trickle over time. While not a VOC, the infamous Asbestos fibers can incubate for over 20 years before presenting as the cause to rather unfortunate symptoms. However, for both VOCs and dangerous materials like Asbestos, there are changes we can make to improve safety.

3D Printing VOC Emission Rates^14,16,19,29

Table Terms:

• Empty table cells indicate that there is no experimental data available, either because relevant studies have not been conducted, or there hasn't been a correlation of concentrations with existing research.
• American Conference of Governmental Industrial Hygienists (ACGIH)
• EU - European Chemicals Agency (ECHA)
• Occupational Safety and Health Administration (OSHA)
• Minimal Risk Levels (MRLs) are intended to serve as a screening tool to help public health professionals identify contaminants and potential health effects that may be of concern at hazardous waste sites.
  
  MRLs are derived for acute (1-14 days), intermediate (14-364 days), and chronic (365 days and longer) exposure durations, and for the oral and inhalation routes of exposure.
  
  Most MRLs contain some degree of uncertainty because of the lack of precise toxicological information on the people who might be most sensitive (e.g. infants, elderly, and nutritionally or immunologically compromised) to effects of hazardous substances. MRLs use a conservative approach to address these uncertainties consistent with the public health principle of prevention. Although human data are preferred, MRLs often must be based on animal studies because relevant human studies are lacking.
• The 8-hour Time Weighted Average (TWA) is an employee's average airborne exposure in any 8-hour work shift of a 40-hour work week that shall not be exceeded. The 8-hour TWA permissible exposure limit (PEL) is the level of exposure established as the highest level of exposure an employee may be exposed to without incurring the risk of adverse health effects. This should not be confused with short-term exposure limits (STELs) or peaks.

How do VOCs from 3D printers relate to odors?

Many VOCs from resin printers and filament are odorless or have limited data

• This table is simplified by presenting the emission rates of each individual VOC as a range.
• Perceptible concentrations represent the thresholds at which we can detect chemicals through our sense of smell. These values are derived from experimental data. When you encounter empty table cells, it signifies that there is a lack of experimental data, either due to the absence of relevant studies or the absence of a correlation between concentrations and existing research.
• The unpleasant odor emitted by resin printers can be attributed to specific VOCs, like Methacrylic Acid. If the concentration of this individual VOC is reduced by 15% in an average-sized room, it can eliminate the odor. However, it's important to note that removing the odor does not necessarily mean the complete elimination of the VOCs.
• The average US room size is roughly 11 x 12 x 8 ft which is 1,056 ft³ or 30 m³.  The average US garage size is roughly 24 x 24 x 8 ft which is 4,608 ft³ or ≈130 m³. A smaller room or closet may only be 250 ft³ or 7 m³.
• Potential concentrations are based on a 6-hour resin or FDM print in a 30 m³ room with no ventilation, filtration, or mixing with external air. The 1 m³ localized concentration serves as an estimate for being in close proximity to the printer, especially if it is in an enclosure like a grow tent with no ventilation.
• Workspaces equipped with active ventilation or filtration systems exhibit significantly lower VOC concentrations.

Perceptible Odors from 3D Printing VOCs

How can I reduce exposure to UFPs from 3D printers?

Venting 3D printer emissions outdoors and using particulate filters will reduce UFP exposure

• Printing at a lower nozzle temperature reduces the UFP emission rate.^31,32
• Printing in a room at 40% relative humidity instead of 70% relative humidity has the potential to reduce the PM2.5 concentration up to ~30%.³⁰
• UFPs can be effectively captured at high rates by using filter media rated as MERV 13+, HEPA, and ULPA.
• A 3D printer's emissions can be exhausted outdoors by using open-air ventilation or by enclosing the printer and using duct with a fan to strategically force the emission outdoors.
  
  Once outdoors, some plastic UFPs are broken down by UV radiation and microorganisms. Other plastic UFPs will persist for years, ending up in the soil, water, and food supply. This highlights the growing need for affordable and highly effective filtration.¹³
• Respirators that use cartridges with P100 HEPA material can capture nearly all of the UFPs that you would otherwise breathe in. The 60921 cartridge from 3M is a combo cartridge with P100 material and activated carbon for VOCs.

How can I reduce exposure to VOCs from 3D printers?

Venting 3D printer emissions outdoors and using activated carbon will reduce VOC exposure

• Printing at a lower nozzle temperature reduces VOC emissions.³²
• The emissions of a 3D printer, especially a resin printer, can be exhausted outdoors by using open-air ventilation or by enclosing the printer and using a duct with a fan to strategically force the emissions outdoors.
  
  Once outdoors, most VOCs are readily broken down by sunlight and microorganisms. For example, Formaldehyde has a half-life of approximately 30 minutes in sunlight, eventually ending up as carbon dioxide.
• Activated carbon granules can capture VOCs and mitigate 3D printer emissions, but the capture efficiency per pass and holding capacity significantly varies between VOCs. For example, activated carbon can capture and retain 25% of its own weight in IPA, while other VOCs such as Formaldehyde can only be retained at 2%.^2,3,4

How can I use ventilation with 3D printers?

All 3D printers should be outside the home in a garage or workshop to maximize ventilation

• Using 3D printers outside the home significantly reduces long-term health risks that could arise when they are used indoors. This is especially important as we continue to spend more time indoors. A garage or workshop is the perfect location for a 3D printer.
• A 3D printer placed in a garage or workshop can simply be positioned on a stable table when printing with PLA since cold temperatures typically won't lead to print failures, provided there are no other potential sources of contamination, such as sawdust.
• Resin and FDM printers that use filament like ABS often require heated chambers to ensure successful prints, and heating an enclosure directly contradicts active ventilation that is required indoors. In a workshop, ventilation fans can be turned on after a print finishes. Indoors, ventilation fans can be turned to low during printing, but the added heat source will consume additional electricity.
• When creating an enclosure for a 3D printer, you have various options ranging from a simple cardboard box or a grow tent to a more sophisticated fume hood or cabinet with active ventilation and filtration. However, it is encouraged to use materials that are fire-proof or resistant, such as glass, mineral wool, mylar, metal, brick, and cement.
• An affordable approach for active ventilation is to use an inline centrifugal or mixed-flow fan along with ductwork to extract contaminated air from the enclosure and expel it outdoors through a sealed window adapter or a hole in the wall, which could be similar to a dryer duct. Typically, a 100 cubic feet per minute (CFM) centrifugal or mixed-flow fan is adequate for an enclosure. The window adapter can be constructed from various materials like fabric, rigid plastic (for portable AC units), plywood, styrofoam insulation, acrylic, or polycarbonate.
• If you don't require an enclosure but want to enhance airflow in your work area, you can utilize the process described above without the enclosure to set up open-air ventilation. Keep in mind that venting an entire workshop or garage will require a fan with substantial flow rate and static pressure. A 24 x24 x 8 ft garage (4,608 ft³) will take 46 minutes for an air change with a 100 CFM fan, whereas a 500 CFM fan will only take 9 minutes, which is 6 air changes per hour.
• When ventilation is needed indoors, it is recommend to use active ventilation with an enclosure, as demonstrated in these Ventilation Simulations. Resin printers should be enclosed and vented out a window. FDM printers should be vented when using engineering materials if filtration is not present.

How can I use filtration with 3D printers?

Particulate media captures billions of UFPs per minute and activated carbon adsorbs VOCs

• Particulate filter media should be used whenever there is a 3D printer indoors that is not being vented outdoors.
• Particulate filter media is encouraged when venting outdoors to limit nanoplastics from eventually entering food and water sources.
• MERV 13-16 filters capture 60-95% of UFPs per pass, which is ideal for recirculating air filtration. HEPA 13-14 filters capture 99.95-99.995% of UFPs per pass, which is ideal for extraction. HEPA filters require a fan with a higher static pressure.^22,23
• HEPA filters are ideal when contaminated air is exiting an enclosure.²³
• ULPA filters are nearly 100% efficient per pass, but these filters are expensive to use and are more appropriate for applications such as hospitals, laboratories, and clean rooms.²³
• Resin printers should not rely on filtration alone, instead it should be used as mitigation within the room or minimizing emissions before exhausting contaminated air out the window.
• Activated carbon can be used to capture VOCs, but it is far from perfect when using only a small amount of carbon. For example, with a carbon bed thickness of 1-2 inches, the capture efficiency for IPA is 40-60% per pass. The exact efficiency will depend on the surface area of the carbon, type of carbon, extent of activation, carbon impregnation, the bed thickness, air flow rate, humidity, and target VOC.¹
• Resin and FDM printer enclosures that use a recirculating air cleaner, allow the air to make multiple passes through both the particulate media and activated carbon, increasing the amount of pollutants captured.

Consumer air cleaners that advertise having activated carbon with the HEPA filter often use very small amounts of carbon in a mesh with many gaps for air to freely flow past the carbon. These will not capture 3D printing VOCs to any meaningful extent.

How often should the filters and carbon be replaced?

Estimating filter lifespan for 3D printing can be complex and will be different for every situation

• MERV and HEPA particulate filters increase in efficiency as they become loaded with dust, debris, and fine particles. However, the pressure required to push air through the filter increases as well. Over time the fan will be derated, lowering the flow rate.
• MERV and HEPA particulate filters should be replaced annually or when the fan is no longer able to sufficiently force air through the dirty filter.
• To estimate how long activated carbon could last for a FDM printer, we need the holding capacity of the activated carbon and the emission rate of VOCs.
  
  With the assumptions of 10% TVOC retention by weight (g/g) at 60% humidity, a TVOC emission rate of 10 mg/hr, and a factor of safety of 3 to 5, 250 g of activated carbon in a sealed recirculating system will become saturated after 500-800 FDM printing hours. This is 20-30 days of 24/7 printing, while 6 hours of printing per day will saturate the carbon within 3-4 months.
  
  The lifespan of carbon will be reduced with increasing humidity, additional printers, engineering filament, and higher nozzle temperatures.
• The simplified answer is that the activated carbon cartridge should be replaced with fresh carbon every 3-6 months or upon the reemergence of odors. More printers at higher temperatures or using engineering filaments will require more frequent replacements. After some time, you will determine the replacement schedule that works for you.

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