Last week, 3D printer manufacturer RIZE became the first company to attain UL 2904 GREENGUARD certification for its RIZE One 3D printer. The certification, which addresses 3D printer particle emissions and safety, followed a multi-year study conducted by the Georgia University of Technology and UL, a leading global safety science company. Now, the Georgia University of Technology has revealed more about the findings of the study and the impact that 3D printing could have on indoor air quality.
Ever since the advent of desktop 3D printing technology, the question of safety has been a concern, especially regarding volatile organic compounds (VOCs) and ultrafine particles (UFPs) in the surrounding air. The study conducted by the Georgia University of Technology and UL has arguably been one of the most comprehensive and in depth investigations into the topic.
The multi-year research project has sought to characterize 3D printer particle emissions in a controlled environment and identify solutions for 3D printer manufacturers and users. The most recent study conducted as part of the ongoing research looked specifically at the particles’ potential for toxicity.
A study published last month in the journal Environmental Science & Technology shows that there is indeed a health risk associated with the particles emitted into the air by FDM 3D printers. Specifically, particles emitted from 3D printers can have a negative impact on indoor air quality and can harm respiratory health.
In the study, the researchers collected particles created by the 3D printing process and conducted various tests to assess the risk and impact of the particles on respiratory cell cultures. As Rodney Weber, a professor at the Georgia Tech School of Earth & Atmospheric Sciences, said: ”All of these tests, which were done at high doses, showed that there is a toxic response to the particles from various types of filaments used by these 3D printers.”
The new findings build upon the team’s existing research which found that hotter printing temperatures resulted in higher emissions, meaning that higher temperature filaments, such as ABS, created more particles than filaments with lower melting temperatures, such as PLA.
Live cell testing
In the recent portion of the multi-year research project, the team partnered with the Weizmann Institute of Science in Israel to test the impact of the 3D printer emissions on live cells. These tests consisted of exposing human respiratory cells and rat immune systems cells to varying concentrations of the 3D printing particles. Interestingly, the tests found that both ABS and PLA had a negative impact on cell viability and that PLA actually prompted a more toxic response. However, these tests did not reflect actual exposures.
“The toxicity tests showed that PLA particles were more toxic than the ABS particles on a per-particle comparison, but because the printers emitted so much more of the ABS, it’s the ABS emissions that end up being more of the concern,” Weber explained. “Taken together, these tests indicate that exposure to these filament particles could over time be as toxic as the air in an urban environment polluted with vehicular or other emissions.”
Analysis of chemical characteristics
The recent study also found that particles emitted when printing ABS filaments had different chemical characteristics than the ABS filament itself. For users, this means that certain brands of ABS may have more particle emissions than others, depending on the additives in the material.
“When the filament companies manufacture a certain type of filament, they may add small mass percentages of other compounds to achieve certain characteristics, but they mostly do not disclose what those additives are,” said Weber. “Because these additives seem to affect the amount of emissions for ABS, and there can be great variability in the type and amount of additives added to ABS, a consumer may buy a certain ABS filament, and it could produce far more emissions than one from a different vendor.”
Another aspect of the study looked at which indoor environments would put users at the most risk. Commercial building settings—like a school or office—were generally found to have a lower risk of emission exposure because of better ventilation systems. 3D printers in a residential setting with less sophisticated or efficient ventilation could have a higher risk of exposure.
How to reduce emissions exposure
Thankfully, there is no need to immediately panic or pack up your desktop 3D printer. UL and Georgia Tech have released a handful of measures that 3D printer users can take to reduce the risk of emissions exposure. They include operating desktop machines in well-ventilated areas, using the lowest nozzle temperature possible (dependent on the filament), standing away from 3D printers while in operation and using 3D printers that have been tested or verified for low emissions.
With more comprehensive knowledge about how 3D printers affect out environment and our health, we can hopefully also count on 3D printer manufacturers to take emissions into consideration when designing new 3D printer models.
Circulating vitamin D levels affect the risk for respiratory symptoms related to indoor air pollution among children with obesity and asthma, findings from a recent study suggest.
Asthma, obesity and air pollution disproportionately affect urban minority populations, and rates of vitamin D deficiency are highest among the black pediatric population, according to the researchers. Therefore, in this study, they sought to determine whether personal vitamin D status in a predominantly black urban cohort of children with asthma mitigates the effects of indoor air particulate exposure and whether any differences exist according to obesity status.
The study included 120 children aged 5 to 12 years with asthma (mean age, 9.7 years; 55% boys; 95% black) from Baltimore who were enrolled from the Domestic Indoor Particulate Matter and Childhood Asthma Morbidity (DISCOVER) study from 2009 to 2015. Serum 25-hydroxyvitamin D (25-[OH]D), asthma symptoms and fine particulate matter (PM2.5) exposure during a 7-day period were evaluated at baseline and every 3 months for 9 months. The average BMI across all children was in the 71st percentile and 36% were considered obese. The mean PM2.5 indoor exposure was 38.2 µg/m3 and the mean 25-(OH)D level was 19.1 ng/mL.
Effects of vitamin D levels
Results showed that lower serum 25-(OH)D levels strengthened the adverse association between PM2.5 and limited activity (P for interaction = .003), trouble breathing (P for interaction = .054), feeling bothered by asthma (P for interaction = .03), having any daytime symptoms (P for interaction = .006), nighttime symptoms (P for interaction = .034) and needing rescue medication (P for interaction = .032) in children with obesity.
According to the data, low 25-(OH)D levels increased the adverse effect of PM2.5 on daytime asthma symptoms (ORPM2.5 = 1.26; P = .049 for a vitamin D level of 15.5 ng/mL), and the effect of PM2.5 on daytime symptoms became stronger with decreasing levels of vitamin D less than 15.5 ng/mL. A similar result was seen for the effects of PM2.5 on nighttime asthma symptoms in children with obesity with 25-(OH)D levels less than 16.4 ng/mL.
Conversely, at extreme levels of indoor air particulate pollution, higher levels of vitamin D protected against an increased likelihood for daytime asthma symptoms driven by PM2.5 among children with obesity (ORvitamin D = 0.87; P = .049 at a PM2.5 concentration of 52.5 µg/m3, with increasingly stronger effects at higher PM2.5 concentrations).
Health concerns at a local high school have prompted a health department inspection.
A Jensen Beach High School mother believes there might be mold inside her daughter’s classroom.
She also worries not enough is being done to make sure her daughter and other students are safe from possible mold exposure.
Leigh Giunta says her daughter has been noticing symptoms of an allergy during her first-period class. Her daughter starts off her school day with 100 minutes inside the high school auditorium, where she takes chorus.
“She’s like ‘Mom, I’m getting this weird rash on my chest when I’m in first period… I have a headache, my eyes hurt, I’m having shortness of breath’… But, it wasn’t happening on the way to school. It wasn’t happening on the way home,” Giunta explained.
The symptoms would go away when her daughter would leave the auditorium.
After a doctor’s visit, Giunta showed WPTV medical paperwork where a doctor told Giunta’s daughter to stay away from the mold, likely what the doctor said was causing her symptoms.
Giunta said other staff members also expressed concern to her about possible mold inside the auditorium. She decided to visit the classroom.
“I said, ‘please take me to the classroom where my daughter is spending 100 minutes. I need to see the environment’…as I walked in I could smell mildew or mold. It hit me like a ton of bricks,” Giunta described.
The Martin County School District’s Chief Operations Officer, Garret Grobowski, said the auditorium has had a leak in the roof since Hurricane Irma.
“This is not a simple repair. The roof has to come off and the connections have to be re-flashed. It’s a really big job,” Grobowski said.
More than a dozen water-damaged ceiling tiles have already been removed, water diverters have been installed, and a dehumidifier has been put in place to keep the air dry.
Giunta called the Florida Department of Health in Martin County, urging them to do an inspection.
The health department confirmed they made a site visit Friday, but after a walkthrough, they did not see or smell signs of mold.
Giunta is not satisfied and still does not want her daughter going back into that classroom.
“I’m not going to put her health at risk because someone from the health department walked in and said’ I don’t see any mold, I don’t smell any mold, but I didn’t test either’,” Giunta explained.
Grobowski said the health department did not recommend testing for mold, and the school district follows their recommendations.
Grobowski confirmed mold tests have never been conducted inside the auditorium.
“We’ve been monitoring the air quality in the building,” Grobowski said. The most recent inspection from the health department shows no air quality tests were conducted.
“What we do is measure temperature and humidity and dew points and grains of moisture. If there’s no moisture, there’s no mold,” Grobowski said.
Grobowski said he is meeting with a contractor Monday to go over replacing the roof. From start to finish, the replacement process could take up to 120-days, he said.
“If you’ve had an issue with a leaky roof for two years, why did it take you two years to suddenly fix it,” Giunta asked.
A new air sampling study done at the Cornell Cooperative Extension building on Griffing Avenue found “unacceptable” indoor air quality due to the presence of high numbers of mold spores in rooms on the second and third floors of the building.
Spore counts of Aspergillus/Penicillium in five rooms made indoor air quality in those rooms unacceptable when an environmental consultant conducted a one-day mold sampling at the building on Aug. 23, according to the consultant’s Sept. 30 draft report, a copy of which was obtained by RiverheadLOCAL.
Aspergillus is a very common mold found both indoors and outdoors and breathing in Aspergillus spores isn’t considered harmful to people with healthy immune systems, according to the federal Centers for Disease Control and Prevention.
“However, for people who have weakened immune systems, breathing in Aspergillus spores can cause an infection in the lungs or sinuses which can spread to other parts of the body,” according to the CDC.
The mold spores can also trigger allergies.
Suffolk County Department of Public Works retained Apex Companies to complete mold air sampling and monitoring services to further evaluate the possible root cause of employee complaints inside the building, the Apex report says.
Previous air sampling and air quality analyses found high relative humidity levels in parts of the building at different times. Excess relative humidity creates an indoor environment conducive to mold growth.
Ascospores, Basidiospores, Cladosporium, Stachybotris/Memnoniella and unidentifiable spores were detected in the building by the air sampling conducted by Apex on Aug. 23. The number of these airborne spores in the samples did not render indoor air quality unacceptable, Apex said.
The building, constructed about 18 years ago, has been largely vacant since June 2018, following widespread reports, during the prior year, of unexplained illnesses by Cornell Cooperative Extension staff, who complained of headaches, nausea, difficulty breathing, asthma attacks, chest pains, lightheadedness, mouth and throat irritations, burning, watery eyes, runny noses, metallic tastes and more, according to documents obtained by RiverheadLOCAL through a Freedom of Information Law request.
Extension staff members, who occupied most of the building, have been relocated to other county offices. Employees in the U.S. Department of Agriculture office on the first floor and the district office of County Legislator Al Krupski on the second floor have remained in the building.
Apex concluded that each of the rooms with unacceptable indoor air quality (rooms 317, 313, 310, 219, and 207) is serviced by the same rooftop HVAC unit, unit number 1. The county legislator’s office suite and the USDA offices are served by two other HVAC units. There are eight rooftop HVAC units serving the building. All are original equipment installed when the building was constructed in 2000-2001.
“Given the aging HVAC infrastructure and documented HVAC system malfunctions/leaks, the rooftop HVAC equipment continues to be considered a source of many of the indoor air quality concerns noted by the occupants,” the Apex report said.
The county legislature in July approved the purchase and installation of eight new rooftop HVAC units for building, at an estimated cost of approximately $450,000.
According to DPW, the county as of July had already spent about $250,000 on investigating and remediating various conditions at the building. Those costs included repairs to HVAC system components, cleaning and testing, including an industrial hygiene investigation by Apex, air sampling for carbon monoxide monitoring by Apex and a previous air quality study done by Enviroscience.
Last month, Suffolk County Comptroller John Kennedy said his office was looking into how the county spent more than $100,000 to investigate the air quality issues at the building before deciding to spend nearly half a million dollars to replace the rooftop HVAC units.
Mold is ubiquitous in nature. Filamentous fungi often produce indoor mold in various environments. Excessive moisture, a carbon source, a moderate temperature (25ºC), and dampness, besides other factors, are supportive elements for the growth of indoor mold. The nature and characteristics of indoor mold is more variable. Sometimes one can see mold growth in indoor environments with the naked eye. However, it is hard to assess health and hygiene effects just by looking at it. Therefore, it is essential to study the indoor mold in order to understand its impacts.
There are a number of techniques available nowadays to isolate and identify the mold from indoor environments. No one technique fits in every scenario, but rather, it should be case specific. Although mold can be examined and evaluated in various ways, an integrated approach to detect mold in indoor environments is described below:
Indoor Mold Sampling
To study the airborne fungi from indoor environments
I Air samples, air samples are collected. Some popular mechanisms are described below for collecting mold/fungal samples from the ambient air.
a. Drum Trap (DT)
Airborne fungal elements are collected on an adhesive tape mounted on a rotating disc powered by an electric motor in an air sealed drum with an orifice. The rotation of the disc is fixed with that of the exposure time. Hirst spore trap, Tilak air samplers, etc. are some common commercially available samplers in this category.
b. Electrostatic Trap (ET)
Fungal/mold samples are collected by drawing air with a constant flow rate and exposure time over media under the influence of an electrostatically charged environment. Charged particles are collected on their positively charged electrode. An Electrostatic Sampling Device (ESD), SASS® 3100, Portable Biohazard Sampler, etc. are good commercially available samplers under this technique.
c. Filterer Trap (FT)
Air samples are drawn on a filter mounted within a closed, airtight chamber by pulling the air through it with a constant airflow rate and exposure time. Micro-orifice uniform deposit impactor (MOUDI), filter made out of cellulose ester, polyvinyl chloride, and polycarbonate are widely used for mold/fungi sampling.
d. Impinger Trap (IP)
In this method, the sample is collected by dissipating the air into an air tight flask containing the media with a constant airflow rate and exposure time. Some common IP samplers include, but are not limited to, Greenberg-Smith impinger, AGI-30, etc.
e. Pore Trap (PT)
Air samples for mold/fungal evaluation are collected on media in an air-tight cylinder by collecting air through a perforated metal plate with a constant airflow rate and exposure time. Anderson’s, Burked, Bio-culture, and Button Aerosol Samplers are routinely used based on this technique.
f. Rotorod Trap (RT)
The airborne fungal particulates are collected on a strip of sticky tape or surface mounted on a mechanical arm/surface attached to a spindle powered by an electric motor that can rotate with a specific number of rotations per minute for a determined exposure time. Rotorod sampler by Sampling Technology, Inc. is one of the most widely used samplers of this category.
g. Spore Trap (ST)
Commonly in this method, a gel-coated glass slip is employed inside an air sampling device and air is pulled out with a constant air flow for a predetermined exposure time depending on the project goals. Flow rate is verified in the field utilizing an in-line flow meter. Air is passed over the coated slide causing airborne fungal particles to adhere to the gel. Some commercially available devices of this category are Air-O-Cell, Micro 5, Allergenco-D, M2, Burkard volumetric samplers, etc.
h. Thermal Trap (TP)
The air samples are collected on a glass slip by placing it around a hot body into ambient air.
II Surface samples
Environmental surfaces are collected to evaluate the mold/fungal infestation in and around indoor environments. Some practical methods for collecting a surface sample are given below.
a. Bulk Sample (BSAM)
Bulk samples are made by collecting, scraping, or cutting a representative of the material/dust suspected for mold/fungi by using aseptic techniques. These samples are transferred to the laboratory in a sterile container for further analysis.
b. Surface Imprint Sample (SISM)
Environmental samples are collected with the help of sticky tape. The sticky side of the tape is placed over the test area and an imprint is taken in order to collect a surface sample for a mold/fungal evaluation. Bio-Scan400is the most accurate (cts/m2) and one of the more commonly used products for collecting surface samples for mold/fungi.
c. Swab Sample (SSAM)
Swab samples are made by swabbing a selected area by using sterile techniques. The collected specimens are transported to the laboratory for further enumeration. A number of companies make cotton or polyester swabs which are available in the market for environmental surface sampling for collecting mold/fungi samples.
d. Vacuum Sample (VSAM)
Dust samples are collected from environmental surfaces suspected for indoor mold with a dust collecting cassette and/or a vacuum sample device under aseptic conditions. The collected samples are transported to the laboratory in a sterile container for further evaluation. Dust sock®, Dust collector, etc. are available in the market for collecting environmental surface samples for mold/fungi.
e. Wipe Sample (WSAM)
Environmental surface samples are collected by means of wiping the selected area suspected for mold/fungi with a sterile gauze pad by following sterile techniques. A leak proof container should be used for transporting these aseptically collected specimens to the laboratory for mold/fungi evaluation. Sterile gauze can be procured in test kits, drug stores, and various other sources to collect environmental samples for testing mold/fungi.
No one sampling method can be used as an absolute standard for collecting environmental samples for the detection and identification of indoor mold. The best way to select a sampling method is to explore the performance of the sampling mechanism and its suitability for the intended project.
Mold Examination and Identification
Isolation of indoor mold collected from environmental samples is challengeable. Depending on the project needs, the trapped particles are isolated by using a suitable buffer such as phosphate buffer saline (PBS), distilled water, etc. Sometimes the collected specimens are directly examined. Some common methodologies are described below for the isolation and identification of mold/fungi from samples collected from the environment.
a. Non-culture method
Microscopic techniques are used to examine and identify the mold/fungal elements from the collected sample. This is a rather inexpensive method with a quick turnaround time. However, many times identification of the indoor mold is limited to a particular taxon.
b. Culture method
In this method, the isolated indoor mold or fungal inoculums on microbiological media are incubated at a required temperature and time for growing the culture. After obtaining the developed culture, microscopic or biochemical techniques are employed for the identification of mold/fungi. While this may be a time taking process, the identification of fungi is often possible both on the genus as well as the species level. Some fungal organisms are media specific; therefore, the selection of microbiological culture media may influence the outcome.
c. Molecular method
Polymerase Chain Reaction (PCR) or other molecular diagnostics methods are used for the identification of mold/fungi from environmental samples. The advantage to this method is a higher accuracy in the identification with a faster turn around time. However, experimental set up is expensive and requires specific training.
d. Biochemical method
In this method, the isolated mold/fungal elements are subject to react with certain biochemicals and after a reaction is observed, a pattern is obtained. In other words, a “Metabolic Fingerprint” is obtained in order to identify the targeted indoor mold.