Poster Session 1

Poster Session 401

Monday, May 23, 2016, 10:00 AM - 12:00 PM

*All posters are available for viewing in the expo hall from Monday 9:00 a.m. through Wednesday 1:00 p.m.​ 


Collection Efficiency of Membrane Filters for Respirable Size-Selective Sampling

J. Soo, T. Lee, M. Kashon, and M. Harper, CDC/NIOSH/HELD/EAB, Morgantown, WV

Objective: To measure the collection efficiency of commercial air sampling filters with polydisperse sodium chloride (NaCl) under different filter pore sizes and sampling flow rates for respirable size selective samplers.

Methods: Collection efficiency experiments were conducted with four different 37 mm diameter membrane filters: mixed cellulose ester (MCE; 0.45, 0.8, 1.2 and 5 µm pore sizes), polycarbonate (0.4, 0.8, 2 and 5 µm pore sizes), polytetrafluoroethylene (PTFE; 0.45, 1, 2 and 5 µm pore sizes), polyvinyl chloride (PVC; 0.8 and 5 µm pore sizes) and silver membrane (0.45, 0.8, 1.2 and 5 µm pore sizes) with polydisperse NaCl in the size range of 10-400 nm. Test aerosols were nebulized and introduced into a calm air chamber through a diffusion dryer and aerosol neutralizer. The testing filters were mounted in a conductive polypropylene cassette within a metal testing tube at the flow rate varied between 1.7 and 11.2 l min-1. A Scanning Mobility Particle Sizer (SMPS, Model 3936, TSI, Inc.) was used to count number particle concentration before (Cin) and after (Cout) test filters. The different pressure across the filter was measured with a digital manometer. The total number of runs was 1044 (29 filter types with different pore sizes x 4 sampling flow rates x 3 filters x 3 replicates).

Results: In general, the collection efficiency varied with flow rate, pore size, and sampling duration. Collection efficiency and pressure drop increased with decreased pore size and increased sampling flow rate, but they differed among filter types and brand. The collection efficiencies of the MCE, PTFE and PVC filters were > 92% under all test conditions while the collection efficiencies of the polycarbonate and silver membrane filters were in the range of 40.2 to 99.6% and 38.6 to >99.9%, respectively.

Conclusions: The present study confirmed that the MCE, PTFE and PVC filters have a relatively large collection efficiency for challenged nanoparticles much smaller than their nominal pore size and have significantly larger sampling efficiency than that of polycarbonate and silver membrane filters at large pore sizes. The collection efficiency of polycarbonate and silver membrane filters varied with flow rate, pore size, and time duration. Although collection efficiency increased with decreased pore size and increased flow rate so, also, did pressure drop across the filter.



Respirable Manganese Exposures During Hand Grinding of Carbon Steel

A. Sauter, Liberty Mutual Insurance, Waukesha, WI; A. De Guzman, Liberty Mutual Insurance Company, Woodbridge, VA

Situation/Problem: Since the reduction of the Manganese TLV® in 2012, much of the focus has been in the welding process, since the fume generated is in the respirable range. Industrial hygiene sampling of Manganese has resulted in overexposures inside the welding helmet of typical welding process such as TIG, MIG and SMAW. An allied task to welding is grinding of metal in preparation for the weld and finish grinding after the weld has been made. This evaluation looks to determine if metal dust from hand grinding can result in overexposures to Mn in the respirable range. Preliminary IH sampling indicates there is a potential exposure to Mn in the respirable range based on our surveys.

Resolution: Sampling using parallel particle impactors (PPI) placed in hand grinder breathing zones was conducted. Isolated hand grinders were selected to limit interference from welding fume exposures.

Results: Sampling results ranged from 55% - 700% of the ACGIH® TLV®.

Lessons learned: Further studies are needed to better characterize and validate the exposure to Manganese containing particulate from grinding tasks.



A Cyclone for End of Shift Silica Measurement

T. Lee, L. Lee, J. Soo, and M. Harper, CDC/NIOSH, Morgantown, WV; J. Hummer and E. Cauda, CDC/NIOSH, Pittsburgh, PA

Objective: 1) To develop a respirable size selective sampler for direct-on-filter silica measurement at the End of Shift (EOS) using a portable Fourier transform infrared spectrometer, and 2) to determine its size selective sampling performance compared to international standards respirable convention.

Methods: A new cyclone, based on the concept of the GS3 respirable dust cyclone, was designed to use a 25-mm filter holder with an effective dust deposition diameter of approximately 8.5 mm. The new sampler (EOS cyclone) was constructed using a 3 dimensional printer loaded with ABS-M30 material. Sampling efficiency of the EOS cyclone was determined using polydisperse glass sphere particles and a time of flight real time direct reading instrument (Aerodynamic Particle Sizer). The test aerosol was generated with a fluidized aerosol generator and the aerosol was introduced into a calm air chamber. The EOS cyclone and a reference sampler were placed horizontally inside the chamber positioned at the same sampling plane. The flow rates of the reference sampler were the same as the test cyclone and the inlet diameter for the reference sampler was calculated so as to obtain a representative sample of the aerosol in calm air conditions. Five EOS cyclones were tested at flow rates of 1.1 and 1.2 l min-1. Using the bias map approach, the measured performance for the EOS cyclone was assessed against the respirable convention defined in American Conference of Governmental Industrial Hygienists (ACGIH®)/Comité Européen de Normalisation (CEN)/International Standards Organization (ISO).

Results: Sampling efficiency of newly developed EOS cyclone was determined. Average cut off diameters of the EOS cyclone at flow rates of 1.1 and 1.2 l min-1 were 4.4±0.06 and 4.1±0.15 µm, respectively. Bias of the EOS cyclone ranged -4-10% at 1.1 l min-1 and -16-4% at 1.2 l min-1. Coal mine dust was used to assess the deposition area on the filter; the preliminary assessment showed an area with an 8.7 mm diameter.

Conclusions: The newly developed EOS cyclone showed minimum bias compared to the international standard respirable convention with flow rates of 1.1 or 1.2 l min-1. The cyclone will be further investigated for direct on filter silica measurement with coal and non-coal mine dusts using a portable Fourier Transform infrared spectrometer.



Development and Validation of Sampling and Analytical Methods for Determination of Mold Spores Concentration in Settled Dust of Heating, Ventilation and Air-Conditioning systems (HVAC)



Silica Exposure During Core Processing in Mining Exploration

S. Kalenge, Occupational Cancer Research Centre, Cancer Care Ontario (CCO), Toronto, ON, Canada; V. Arrandale, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada

Objective: Although, there is extensive research on occupational exposure in active (production phase) mines, there is limited information on the occupational exposure of workers during the exploration phase of mining. The aim of this study was to assess personal exposure to airborne particulates and crystalline silica in a core processing facility that was part of a mining exploration project in Northern Ontario, Canada.

Methods: Personal air samples were collected on pre-weighed 37mm PVC filters (5 µ) with 3-piece open-face cassettes attached to SKC aluminum cyclones. All samples were analyzed for respirable particulates using gravimetric analysis (NIOSH Method 0500) as well as respirable crystalline silica using Fourier Transform Infra-red spectroscopy (FT-IR) (NIOSH Method 7602). Time weighted average concentrations were calculated for respirable particulate, respirable quartz and respirable cristobalite/tridymite.

Results: Sixteen personal air samples were analyzed. Full shift respirable particulate exposure ranged from 0.069 to 2.24 mg m−3 with a geometric mean (GM) of 0.28 mg m−3 and a geometric standard deviation of 2.76. The Ontario exposure limit for respirable particulate is 3 mg m−3. Respirable particulate concentrations were significantly higher among workers in the core cutting area compared to the core logging area (GM 0.43 mg m−3 vs. 0.088 mg m−3; p=0.02). No samples had detectible levels of cristobalite / tridymite. Full shift quartz exposure ranged from 3.3 to 55.4 µg m−3 with a geometric mean (GM) of 6.53 µg m−3 and a geometric standard deviation of 2.67. The Ontario exposure limit for respirable quartz is 100 µg m−3. Quartz concentrations were higher among workers in the core cutting and core sorting areas, as compared to those in the core logging area. No pairwise differences reached statistical significance.

Conclusions: Workers employed in core processing facilities as part of mining exploration activities are exposed to respirable particulates and silica. Although no individual measurements exceeded the Ontario occupational exposure limits, some personal exposures approached the limits among workers who were performing core cutting tasks. Exposure to respirable particulates and silica in mining exploration should be monitored as exposure controls may be needed.



High Flow Rate Thoracic Size Selective Samplers

T. Lee and M. Harper, NIOSH, Morgantown, WV

Objective: To calibrate high flow rate thoracic size selective samplers (GK4.126 and FSP10), which can be used for dual fraction size selective sampling to measure the respirable and thoracic size fractions.

Methods: Six different sizes of monodisperse ammonium fluorescein aerosols were generated using a vibrating orifice aerosol generator. Airborne particles were collected with samplers in a cylindrical calm air test chamber. After sampling, the fluorescent intensity was measured using a luminescence spectrometer. Because the size interval of the Aerodynamic Particle Sizer for particles > 8 µm is large (> 0.6 µm), projected area diameters of the monodisperse ammonium fluorescein particles were measured with a field emission scanning electron microscopy. At least 100 particles of projected area diameters were measured for each particle size. Equivalent volume diameter was calculated using average project area diameters. From equivalent volume diameter, an aerodynamic diameter was calculated with the particle’s specific gravity and dynamic shape factor. Three repetitions with each sampler units were conducted at each size of particle size. The measured performance data for the cyclone was assessed against the thoracic target convention defined in American Conference of Governmental Industrial Hygienists (ACGIH®)/Comité Européen de Normalisation (CEN)/International Standards Organization (ISO).

Results: The measured cut off diameters (d50s) for the GK2.69, GK4.126 and FSP10 cyclones were 9.7, 9.8, and 10.9 µm, respectively. Bias maps for the cyclones were generated from the measured sampling efficiency compared to the ACGIH/CEN/ISO thoracic convention for a range of mass median aerodynamic diameter 1-30 µm with geometric standard deviation of 1.5-4. The GK2.69 cyclone was tested at a flow rate of 1.6 l min-1 as a reference sampler for comparison and its performance was similar to that observed in a previous study. The estimated biases for the measured experimental GK2.69 cyclone performance compared with ACGIH®/CEN/ISO thoracic convention were negative up to 25 % while those of the GK4.126 and FSP10 cyclones were positive up to 7 and 11 %, respectively.

Conclusions: High flow rate cyclones normally used for respirable size selective sampling were calibrated to measure the thoracic size fraction. The recommended flow rates of GK4.126 and FSP10 cyclones for thoracic size selective sampling are 3.5 and 4.0 l min-1, respectively. Higher flow rate samplers will collect more sample for subsequent analysis resulting in an increase in sensitivity making them more useful for the measurement of low concentration aerosols or during short term or task specific sampling. The cyclones should be further investigated for sampling of specific occupational aerosols.



Evaluation of Bioaerosol Properties and Antibiotic Resistance in Animal Hospital

C. Lai, M. Wang, and C. Chan, Department of Occupational Safety & Health, Chung Shan Medical University, Taichung, Taiwan; W. Lee, Veterinary Medical Teaching Hospital of National Chung-Hsing University, Taichung, Taiwan; A. Kuo, Chung Shan Medical University Hospital, Taichung, Taiwan

Objective: Biological pollution deeply impacts health of human beings and bioaerosols can result in infection or allergy. Under different animal host (including human) and interaction of different environments, microorganisms may have a resistance to antibiotics. In this study, we sampled in animal hospitals in order to investigate microorganism species, concentration and resistance to antibiotics of bioaerosols at different temperatures, and evaluate their hazards to human health.

Methods: In this study, three types of bioaerosol samplers like Andersen six stage, AGI-30 and BioSampler were used for sampling bacteria and fungi in four seasons. The sampling locations were respectively the hall and the animal wards of an animal hospital in central Taiwan. Bacteria were cultured by tryptone soya agar (TSA) at 25°C, 37°C and 42°C. Colonial morphology was observed and counted after gram stain. The full automatic microorganism identification instrument BD Phoenix™ was used to identify strains and analyze resistance to antibiotics. Fungi were cultured by malt extract agar (MEA) at 25°C. The Atlas of Clinical Fungi Identification index was used to identify fungi genus and strains.

Results: The result showed that the Andersen six stage collected dominant bacteria like Micrococcus spp. and Staphylococcus spp. from bacteria at each stage, and collected Cladosporium spp. and Penicillium spp. from fungi. The AGI-30 and BioSampler samplers all cultivated Staphylococcus spp. (7 species) and Micrococcus spp. (2 species) at three different temperatures (25°C, 37°C and 42°C). By analysis, the resistance to antibiotics about Staphylococcus spp. collected from hall and wards could resist Ampicillin, Oxacillin and Penicillin G. Staphylococcus spp. (7 species) collected from the hall had an extensive resistance to antibiotics.

Conclusions: All the results showed that most bioaerosols are mainly environmental bacteria, but they still are opportunistic pathogenic bacteria, which can contaminate therapeutic apparatus and result in hospital nosocomial infection and allergy.



Sampling Evaluation of Bioaerosol and Antibiotic Resistant Characteristics in Intensive Care Unit

C. Lai, N. Wu, Y. Lin, and A. Kuo, Chung Shan Medical University Hospital, Taichung, Taiwan

Objective: Our research was based in a medical center’s Internal Medicine Intensive Care Unit (MICU)and Surgery Intensive Care Unit (SICU) located in central Taiwan. The research objective focus was on the bioaerosols and their antibiotic resistant characteristics in both locations.

Methods: Three bioaerosol samplers were utilized (Anderson six-stage, AGI-30, and BioSampler) for sampling before and during patient visiting. Upon acquisition of samples, they were inoculated and cultured on BBL ™ Trypticase ™ Soy Agar (with 5% Sheep Blood) medium for growth. The bacterial colonies were later identified and analyzed for antibiotic-resistant characteristics via BD Phoenix ™medium ted microbial identification and susceptibility test analyzer.

Results: Research results have showed from the bioaerosol samples acquired within the MICU that dominant concentration of bacteria and fungi were below the cut off size of 3.3 μm. Thus, they had a high possibility to enter human lung’s alveolar regions of the body, thereby causing opportunistic infections. The factor of season and air change rate per hour did not statistically associate with bioaerosol concentration (P>0.05); However, factor of patient visiting and temperature, relative humidity during sampling showed statistically agreement with bioaerosol concentration (P<0.001). In terms of bacterial strain identification, Gram-positive bacteria were mainly isolated with risk group (RG)of II. In the MICU, antibiotic resistant strains were identified and 63.5 % were resistant to National Health Insurance Administration (NHIA)designated first (17 types) and second (18 types) line antibiotics. This phenomenon could very likely affect the medical staffs working within the hospital environment.

Conclusions: As a result, recommendations for MICU ventilation designs should be carefully evaluated for the effectiveness of controlling nosocomial infections as well as proper implementation of personal protective equipment in order to reduce bioaerosol opportunistic infections and harmful exposure effects.



Comparative Evaluation of Strategies for Assessing Occupational Exposure to Carbonaceous Nanomaterials

M. Debia, C. Catto, and M. Skulinova, Université de Montréal, Montréal, QC, Canada; G. L'Espérance and C. Allard, Polytechnique Montréal, Montréal, QC, Canada; J. Kroeger, Raymor Industries Inc., Boisbriand, QC, Canada

Objective: Carbonaceous fibrous nanomaterials (CARF) include carbon nanotubes (CNTs), which can be single-walled (SWCNTs), double-walled (DWCNTs) or multi-walled (MWCNTs), and carbon nanofibers (CNFs). Pulmonary health effects have been associated to these compounds. A cautious and reliable exposure assessment is thus needed to control the risk and ensure workers’ protection. This study aims at comparing various methods used to assess occupational exposures to CARF.

Methods: Personal sampling was carried out during the recovery and cleaning operations of SWCNTs’ production process in a primary manufacturer. Elemental Carbon (EC) was measured following the NIOSH 504 method as marker for (i) respirable fraction of airborne particles samples monitored using cassettes equipped with quartz filters and BGI cyclone (GK 2.69) [REC-CYC], (ii) respirable fraction of airborne particles monitored using personal particles impactors (PPI) equipped with quartz filters [REC-PPI], and (iii) thoracic fraction of airborne particles monitored using PPIs with quartz filters [TEC-PPI]. Airborne particles were also collected on copper numbered microscopy grids using a mini particulate sampler (MPS) and SWCNT structures were counted by (a) Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) and (b) Raman spectroscopy analysis.

Results: EC concentrations ranged from non-detected (n=3), 4 to 58 µg/m3 (n=5), and 40 to 70 µg/m3 (n=5) for REC-CYC, REC-PPI and TEC-PPI, respectively. SEM/TEM analyses showed large agglomerates structures between few hundred nanometers to tens of micrometers. Several SWCNT structures were attached to large dumps of spherical particles identified as black carbon, nickel and iron. Concentration of SWCNTs was 0.058 SWCNT/cm3. Raman analysis indicated that less than 5 % of particles collected on the grid were SWCNTs.

Conclusions: Quantifying occupational exposures to CARF is challenging since the NIOSH 5040 method is not specific to carbon contained in CARF but include all form of elemental carbon such as the carbon contained in the black carbon used to produce CARBF. MPS is well suited to collect particles and proceed later to non-destructive quantification by counting CNT structures without any handling and disturbance of the collected materials and Raman analysis.



Workplace Measurements of Semiconductor Nanowires During Production at a Small-Scale Company

M. Hedmer and H. Tinnerberg, Occupational and Environmental Medicine, Lund University, Lund, Sweden; C. Isaxon, P. Nilsson, J. Rissler, A. Gudmundsson, M. Bohgard, and J. Pagel, Ergonomics and Aerosol Technology, Lund University, Lund, Sweden; L. Ludvigsson and M. Messing, Solid State Physics, Lund University, Lund, Sweden

Objective: The industrial use of novel manufactured nanomaterials with enhanced or completely new properties is increasing globally. During the last decade, there have been growing concerns of adverse health effects of nanofibers e.g. carbon nanotubes. A new type of nanofibers is the semiconductor nanowires (NW), which have the potential to be used in applications e.g. solar cells, light-emitting diodes and batteries. Semiconductor NWs are fiber shaped manufactured nano-objects with a length of 1-2 µm. The industrial use is growing as well as the potential for worker exposure. Aerotaxy is a new method for industrial mass production of NWs. Production takes place in closed reactor systems and NWs of GaAs are grown in the gas phase on catalytic seed nanoparticles of Au by addition of gaseous precursor molecules. The aerotaxy reactor system was opened up during maintenance e.g. manual cleaning operation. The aim was to quantify the personal breathing zone (PBZ) exposure and emissions of NWs to air during production work at a small-scale company. The potential for dermal exposure was also assessed.

Methods: PBZ and emission filter samples were collected on 25 mm filters for 8 production stages for determination of particle number concentration, mass concentration, and metal content. Also direct reading instruments were used in the emission zone and background to measure particle number concentrations and number size distributions with high time resolution. Tape samples (N=14) were collected from workplace surfaces in the facility. The samples were gravimetric analysed with SEM and ICP-MS.

Results: Concentrations up to 98 NWs/cm3 were detected in the emission zone during the 8 production stages. In the PBZ, a concentration of 0.025 NWs/cm3 was measured. The emitted NWs had a mean length of 4 µm (range 0.5-24 µm). One surface inside the tool enclosure was found to be contaminated with NWs, Au and semiconductor material. The cleaning operation was identified as the production stage with highest emission.

Conclusions: During maintenance NWs, particles of Au and semiconductor material were emitted to the workplace air and surface. The emitted NWs were longer than the produced ones. The personal protective equipment used for this production stage was essential to avoid worker exposure. The company has now modified the cleaning operation and it is now performed within the closed system.



Evaluation of Bacteria Reducing Efficiency Using Bactericide Under Full Scale Field Study—A Negative Pressure Pattern Testing

C. Lai, Y. Wang, Y. Lee, and A. Ku, Chung Shan Medical University, Taichung, Taiwan

Objective: Many nosocomial infections of patients are derived from secondary infections during their hospital stay via pathogens or by its toxins. Thereby, causing local or systemic adverse reactions in patients, that are not present prior to admission or not at a latency stage. The major nosocomial infection route can be divided into two pathways, airborne and contact transmission. According to recent research, general disinfection methods are direct contact to pathogens but seldom relate to airborne disinfection method. Our research first conducted the paper disk diffusion test to initially understand the effectiveness of the bactericides. Then, in a full scale test ventilation laboratory equipped with stable (ΔP=0 pa), negative (ΔP=-8 pa), or positive (ΔP=+8 pa) pressure ventilation. The main objective was to evaluate bacteria reducing efficiency using bactericide under full scale field study.

Methods: The dimensions of full scale test laboratory were 3 x 3 x 3 meters, that could provide different dilution ventilation flow patterns, included the short circuit and displacement pattern. Moreover, the operation parameter also compared different air change rates per hour (ACH). The experimental procedure was to deploy bacteria and bactericides and test their effective bacteria reducing rate under different flow patterns and pressure drop (negative, stable, positive) setting. For experimental comparison, the bacteria of Bacillus subtilis was used as challenge aerosol while the Collison Atomizer was used for producing the bioaerosol and the bactericide. The bioaerosol disinfection efficiency was compared via the Andersen Single Stage Microbial Sampler. As for the bactericides, different proportions of diluted bactericides were atomized and sprayed in the full scale test laboratory with the selection of hypochlorous acid, terpinen-4-ol, and lemon grass oil.

Results: The research results indicated that most bactericides worked most effectively under negative pressured airflow field environments. There was a significant reduction in bactericidal effect under positive or stable pressured environments. In particular, the hypochlorous acid showed a high bactericidal effect under different pressure drops. Under the short circuit airflow field, both the terpinen-4-ol and lemon grass oil showed significant bactericidal reducing effect. The resulted bactericidal rates were also related to the particle sizes of the bactericides and the experimental bacteria used.

Conclusions: The resulted bactericidal rates were also related to the particle sizes of the bactericides and the experimental bacteria used. The greater the difference of the particle sizes between the bactericides and experimental bacteria used, the greater was their coagulation, which may produce a better bactericidal reducing effect.



Physicochemical Properties of the Powder By-Products Generated from a Metallization Process and Its 1st Scrubber in the Semiconductor Industry

K. Choi, M. Jung, and H. An, Samsung Health Research Institute, Samsung Electronics, Yongin-Si, Korea (the Republic of)

Objective: It is feared that the formation of powder by-products and their attachment on the equipment chambers and parts during the ongoing semiconductor process, may result in workers’ exposure during maintenance. Little is known about detailed physicochemical characterization of powder by-products generated from semiconductor processes. The aim of this study is to identify the physicochemical properties such as chemical composition, size, shape and crystal structure of powder by-products generated from a metallization process and its 1st scrubber in the semiconductor industry.

Methods: This study was conducted in three 200 mm semiconductor wafer fabrication facilities. The powder samples were collected from their inner chamber during maintenance of W-plug process equipment using tungsten hexafluoride (WF6) and silane (SiH4) as precursor materials and its 1st scrubber. The chemical composition, size and shape of the powder particles were determined by field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) equipped with energy dispersive spectroscopy (EDS), respectively. The crystal structure of the powders was analyzed by X-ray diffraction (XRD).

Results: From the SEM-EDS and TEM-EDS analyses, the O and W were mainly detected which indicates the powder by-products are tungsten trioxide (WO3), whereas Al, F and Ti were detected as low peaks. The powder particles are spherical and nearly spherical. The particle size collected from process equipment and its 1st scrubber showed 10-20 nm (aggregates: 55-90 nm) and 16-20 nm (aggregates: 80-120 nm) as primary particles, respectively. The XRD patterns of the yellow powder by-products exhibit five peaks at 23.80˚, 33.90˚, 41.74˚, 48.86˚ and 54.78˚, which correspond to the (200), (220), (222), (400) planes of a cubic WO3.

Conclusions: This study should provide useful information for the development of alternative strategies to improve the work environment and workers’ health.



Experimental Study of Surgical Smoke and Its Control

T. Lee, J. Soo, R. LeBouf, D. Burns, and M. Harper, CDC/NIOSH, Morgantown, WV; D. Novak, CDC/NIOSH, Pittsburgh, PA; J. Bowers, Ruby Memorial Hospital, Morgantown, WV

Objective: To evaluate airborne particulates and volatile organic compounds (VOCs) from surgical smoke in an experimental settings when the local exhaust ventilation (LEV) system is present or absent.

Methods: Airborne particles and VOCs were collected for 45 minutes in four different experimental settings: 1) background (without any activity), 2) smoke generation without LEV utilization, 3) smoke generation with LEV control (wall irrigation suction unit with an in-line ultra-low penetration air (ULPA) filter positioned between the wall suction and suction canisters), and 4) smoke generation with LEV control (smoke evacuation system (PlumeSafe®Turbo) installed a four-stages filter including charcoal and ULPA filters). Surgical smoke was generated from excised human tissues in unoccupied operating rooms using an electrocautery surgical device for 15 minutes. Flow rate of both LEVs was approximately 35 l min-1 (normal setting at the hospital) and suction was maintained within 2 inches of generation point. A total of 4 experiments were carried out. Particle number and mass concentrations were measured in real time with direct reading instruments including a Condensation Particle Counter (CPC), a DustTrak, a Scanning Mobility Particle Sizer (SMPS), an Aerodynamic Particle Sizer (APS) and a BioTrak. VOCs from the surgical smoke were collected using evacuated canisters both area and personal samples (from experimental personnel) following NIOSH draft canister method for VOCs in air. The canister samples were analyzed using a pre-concentrator and gas chromatography-mass spectrometry system.

Results: The average particle number concentrations of background, without LEV, wall suction and smoke evacuation system measured with the CPC were 300, 9000, 2300 and 1500 particles cm-3, respectively. The average particle mass concentrations of background, without LEV, wall suction and smoke evacuation system measured with the DustTrak were 3, 24, 8 and 3 µg m-3, respectively. Count median particle diameters from the SMPS measurements were found at 84 nm (background), 90 nm (without LEV), 81 nm (wall suction unit) and 29 nm (smoke evacuation system). Particle number concentration from the SMPS were close to the concentrations from the CPC in all experimental settings. Particle number concentration in particle size > 0.5 µm including viable particles were not large (< 200 cm-3) in all experimental settings. Ethanol and isopropyl alcohol were domina​​nt VOCs from all canister samples. Acetaldehyde, acetone, acetonitrile, benzene, hexane, styrene and toluene were detected in grab samples but their concentrations were in low range (< 100 ppb).

Conclusions: Utilization of the LEVs for surgical smoke control can reduce possible exposure to healthcare workers in operating rooms but airborne ultrafine particles still remain.​