Analysis of time series of particle size distributions in nano exposure assessment

Entink, Rinke H. Klein; Bekker, Cindy; Fransman, Wouter; Brouwer, D.H.

doi:10.1016/j.jaerosci.2014.11.007

Cited by 11 publications

(4 citation statements)

References 10 publications

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“…Temporal changes in particle size distributions (including median and variance) from realtime FMPS measurements were estimated using a two-level Bayesian model with a Markov chain Monte Carlo algorithm developed by Klein Entink et al [30] We used 1-min averages of FMPS real-time measurements for two emission tests as examples. A run of the Pegasus Touch SLA printer had 315 one-minute average measurements, of which, the 1 st to 35 th 1min average measurements were background, 36 th to 191 st were collected during the printing phase, and the 192 nd to 315 th were the post-printing phase.…”

Section: Discussionmentioning

confidence: 99%

“…Analyses were conducted in R 3.3.1 using the "NanoPSDA" package (R Foundation for Statistical Computing, Vienna, Austria). [31,32] Mean yield and particle size distribution values were compared using one-way Analysis of Variance (ANOVA) models. Specific pairwise differences between printers or types (SLA or DLP) were compared using Tukey's tests.…”

Section: Discussionmentioning

confidence: 99%

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Particle and vapor emissions from vat polymerization desktop-scale 3-dimensional printers

Stefaniak

Bowers

Knepp

et al. 2019

Journal of Occupational and Environmental Hygiene

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Little is known about emissions and exposure potential from vat polymerization additive manufacturing, a process that uses light-activated polymerization of a resin to build an object. Five vat polymerization printers (three stereolithography (SLA) and two digital light processing (DLP) were evaluated individually in a 12.85 m 3 chamber. Aerosols (number, size) and total volatile organic compounds (TVOC) were measured using real-time monitors. Carbonyl vapors and particulate matter were collected for offline analysis using impingers and filters, respectively. During printing, particle emission yields (#/g printed) ranged from 1.3 ± 0.3 to 2.8 ± 2.6 × 10 8 (SLA printers) and from 3.3 ± 1.5 to 9.2 ± 3.0 × 10 8 (DLP printers). Yields for number of particles with sizes 5.6 to 560 nm (#/g printed) were 0.8 ± 0.1 to 2.1 ± 0.9 × 10 10 and from 1.1 ± 0.3 to 4.0 ± 1.2 × 10 10 for SLA and DLP printers, respectively. TVOC yield values (μg/g printed) ranged from 161 ± 47 to 322 ± 229 (SLA printers) and from 1281 ± 313 to 1931 ± 234 (DLP printers). Geometric mean mobility particle sizes were 41.1-45.1 nm for SLA printers and 15.3-28.8 nm for DLP printers. Mean particle and TVOC yields were statistically significantly higher and mean particle sizes were significantly smaller for DLP printers compared with SLA printers (p < 0.05). Energy dispersive X-ray analysis of individual particles qualitatively identified potential occupational carcinogens (chromium, nickel) as well as reactive metals implicated in generation of reactive oxygen species (iron, zinc). Lung deposition modeling indicates that about 15-37% of emitted particles would deposit in the pulmonary region (alveoli). Benzaldehyde (1.0-2.3 ppb) and acetone (0.7-18.0 ppb) were quantified in emissions from four of the printers and 4-oxopentanal (0.07 ppb) was detectable in the emissions from one printer. Vat polymerization printers emitted nanoscale particles that contained potential carcinogens, sensitizers, and reactive metals as well as CONTACT A. B. Stefaniak,

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Particle and vapor emissions from vat polymerization desktop-scale 3-dimensional printers

Stefaniak

Bowers

Knepp

et al. 2019

Journal of Occupational and Environmental Hygiene

View full text Add to dashboard Cite

show abstract

“…Temporal changes in particle size distributions (including median and variance) from real-time FMPS measurements were estimated using a two-level Bayesian model with a Markov chain Monte Carlo algorithm developed by Klein Entink et al 30 We used 1-min averages of FMPS real-time measurements. Analyses were conducted in R 3.3.1 using the “NanoPSDA” package.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of emissions and exposures at workplaces using desktop 3-dimensional printers

Stefaniak¹,

Johnson²,

Preez³

et al. 2019

J. Chem. Health Saf.

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There is a paucity of data on additive manufacturing process emissions and personal exposures in real-world workplaces. Hence, we evaluated atmospheres in four workplaces utilizing desktop “3-dimensional” (3-d) printers [fused filament fabrication (FFF) and sheer] for production, prototyping, or research. Airborne particle diameter and number concentration and total volatile organic compound concentrations were measured using real-time instruments. Airborne particles and volatile organic compounds were collected using time-integrated sampling techniques for off-line analysis. Personal exposures for metals and volatile organic compounds were measured in the breathing zone of operators. All 3-d printers that were monitored released ultrafine and fine particles and organic vapors into workplace air. Particle number-based emission rates (#/min) ranged from 9.4 × 109 to 4.4 × 1011 (n = 9samples) for FFF3-d printers and from 1.9 to 3.8 × 109 (n = 2 samples) for a sheer 3-d printer. The large variability in emission rate values reflected variability from the printers as well as differences in printer design, operating conditions, and feedstock materials among printers. A custom-built ventilated enclosure evaluated at one facility was capable of reducing particle number and total organic chemical concentrations by 99.7% and 53.2%, respectively. Carbonyl compounds were detected in room air; however, none were specifically attributed to the 3-d printing process. Personal exposure to metals (aluminum, iron) and 12 different organic chemicals were all below applicable NIOSH Recommended Exposure Limit values, but results are not reflective of all possible exposure scenarios. More research is needed to understand 3-d printer emissions, exposures, and efficacy of engineering controls in occupational settings.

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“…In stage 1, ARIMA models were used to take into account the pattern of autocorrelation in the sequential measurements collected with real-time instruments. In a stepwise approach that was previously described by Klein Entink et al (2011) andKlein Entink et al (2015), the data were forced for stationarity as assumed by an ARIMA model. A second-order moving-average model was applied (100 iterations), which had the best fit with the measurement data.…”

Section: Statistical Analysesmentioning

confidence: 99%

Relative Differences in Concentration Levels during Sawing and Drilling of Car Bumpers Containing MWCNT and Organic Pigment

Kuijpers

Pronk²,

Koivisto

et al. 2019

Annals of Work Exposures and Health

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Introduction: Knowledge on the exposure characteristics, including release of nanomaterials, is especially needed in the later stages of nano-enabled products' life cycles to perform better occupational risk assessments. The objective of this study was to assess the concentrations during sawing and drilling in car bumpers containing multi-walled carbon nanotubes (MWCNTs) and nanosized organic pigment (OP) under variable realistic workplace situations related to the ventilation in the room and machine settings. Methods: Twelve different experiments were performed in triplicate (N = 36) using tools powered by induction engines that allow interference-free particle measurements. A DiSCmini was used to measure particle number concentrations, whereas particle size distributions were measured using Aerodynamic Particle Sizer (TSI), Scanning Mobility Particle Sizer (TSI), and Electrical Low Pressure Impactor (Dekati). In addition, inhalable particles were sampled using IOM samplers on filters for scanning electron microscope/energy-dispersive X-ray spectrometry (SEM/EDX) analyses. Data were analysed to estimate the effects of individual exposure determinants, in a two-stage modelling strategy using Autoregressive Integrated Moving Average models (stage 1) and subsequently combining first stage results in simulations using multiple linear regression models (stage 2). Results: In sawing experiments, partly melted carbon-rich particles (mainly ~2 to ~8 µm) were identified with SEM/EDX, whereas drilling experiments revealed no activity-related particles. In addition, no pristine engineered nanoparticles (MWCNTs and OP) were observed to be liberated from the matrix. Statistical analyses showed significant effects of a higher sawing speed, a reduction in air concentration due to mechanical ventilation, and less exposure during sawing of car bumpers containing MWCNTs compared to bumpers containing OP.

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Analysis of time series of particle size distributions in nano exposure assessment

Cited by 11 publications

References 10 publications

Particle and vapor emissions from vat polymerization desktop-scale 3-dimensional printers

Particle and vapor emissions from vat polymerization desktop-scale 3-dimensional printers

Evaluation of emissions and exposures at workplaces using desktop 3-dimensional printers

Relative Differences in Concentration Levels during Sawing and Drilling of Car Bumpers Containing MWCNT and Organic Pigment

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