Search

Unlabelled: Direct-reading organic vapor monitors are often used to measure volatile organic compound concentrations in complex chemical gas mixtures. However, there is a paucity of data on the impact of multiple gases on monitor performance, even though it is known that monitor sensitivity may vary by chemical. This study investigated the effects of interferents on the performance of the MIRAN SapphIRe Portable Ambient Air Analyzer (SAP) and Century Portable Toxic Vapor Analyzer (TVA-1000) when sampling a specific agent of interest (cyclohexane). The TVA-1000 contained a dual detector: a photoionization detector (PID) and a flame ionization detector (FID). Three devices of each monitor were challenged with different combinations of cyclohexane and potential interferent vapors (hexane, methyl ethyl ketone, trichloroethylene, and toluene) at 21°C and 90% relative humidity (RH), an extreme environmental condition. Five replicates at four target concentrations were tested: 30, 150, 300, and 475 ppm. Multiple proportions of cyclohexane to interferent enabled the determination of the interferent effect on monitor performance. The monitor concentrations were compared to reference concentrations measured using NIOSH Method 1500. Three scenarios were investigated: no response factor, cyclohexane response factor, and weighted-mixed response factor applied. False negatives occurred more frequently for PID (21.1%), followed by FID (4.8%) and SAP (0.2%). Measurements from all monitors generally had a positive bias compared to the reference measurements. Some monitor measurements exceeded twice the reference concentrations: PID (36.8%), SAP (19.8%), and FID (6.3%). Evaluation of the 95% confidence intervals indicated that performance of all monitors varied by concentration. In addition, the performance of the PID and SAP varied by presence of an interfering compound, especially toluene and hexane for the PID and trichloroethylene for the SAP. Variability and bias associated with all these monitors preclude supplanting traditional sorbent-based tube methods for measuring volatile organic compounds (VOCs), especially for compliance monitoring., Implications: Industrial hygienists need to use care when using any of the three monitor detection types to measure the concentration of unknown chemical mixtures. Monitor performance is affected by the presence of interferents. Application of manufacturer recommended response factors may not adequately scale measurements to minimize monitor bias when compared to standard reference methods. Users should calibrate their monitors to a known reference method prior to use, if possible. Each of the monitors has its own limitations, which should be considered to ensure quality measurements are reported.

Background: Healthcare workers have an elevated prevalence of asthma and related symptoms associated with the use of cleaning/disinfecting products. The objective of this study was to identify and characterize cleaning/disinfecting tasks and products used among hospital occupations., Methods: Workers from 14 occupations at five hospitals were monitored for 216 shifts, and work tasks and products used were recorded at five-minute intervals. The major chemical constituents of each product were identified from safety data sheets., Results: Cleaning and disinfecting tasks were performed with a high frequency at least once per shift in many occupations. Medical equipment preparers, housekeepers, floor strippers/waxers, and endoscopy technicians spent on average 108-177 min/shift performing cleaning/disinfecting tasks. Many occupations used products containing amines and quaternary ammonium compounds for >100 min/shift., Conclusions: This analysis demonstrates that many occupations besides housekeeping incur exposures to cleaning/disinfecting products, albeit for different durations and using products containing different chemicals., (© 2014 Wiley Periodicals, Inc.)

Objectives: To identify and summarise volatile organic compound (VOC) exposure profiles of healthcare occupations., Methods: Personal (n=143) and mobile area (n=207) evacuated canisters were collected and analysed by a gas chromatograph/mass spectrometer to assess exposures to 14 VOCs among 14 healthcare occupations in five hospitals. Participants were volunteers identified by their supervisors. Summary statistics were calculated by occupation. Principal component analysis (PCA) was used to reduce the 14 analyte inputs to five orthogonal factors and identify occupations that were associated with these factors. Linear regressions were used to assess the association between personal and mobile area samples., Results: Exposure profiles differed among occupations; ethanol had the highest geometric mean (GM) among nursing assistants (∼4900 and ∼1900 µg/m(3), personal and area), and 2-propanol had the highest GM among medical equipment preparers (∼4600 and ∼2000 µg/m(3), personal and area). The highest total personal VOC exposures were among nursing assistants (∼9200 µg/m(3)), licensed practical nurses (∼8700 µg/m(3)) and medical equipment preparers (∼7900 µg/m(3)). The influence of the PCA factors developed from personal exposure estimates varied by occupation, which enabled a comparative assessment of occupations. For example, factor 1, indicative of solvent use, was positively correlated with clinical laboratory and floor stripping/waxing occupations and tasks. Overall, a significant correlation was observed (r=0.88) between matched personal and mobile area samples, but varied considerably by analyte (r=0.23-0.64)., Conclusions: Healthcare workers are exposed to a variety of chemicals that vary with the activities and products used during activities. These VOC profiles are useful for estimating exposures for occupational hazard ranking for industrial hygienists as well as epidemiological studies., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Objectives: To better understand respiratory symptoms and lung function in flavouring manufacturing workers., Methods: We offered a questionnaire and lung function testing to the current workforce of a flavouring manufacturing facility that had transitioned away from diacetyl and towards substitutes in recent years. We examined symptoms, spirometric parameters and diffusing capacity measurements by exposure variables, including facility tenure and time spent daily in production areas. We used linear and logistic regression to develop final models adjusted for age and smoking status., Results: A total of 367 (93%) current workers participated. Shortness of breath was twice as common in those with tenure ≥ 7 years (OR 2.0, 95% CI 1.1 to 3.6). Other chest symptoms were associated with time spent daily in production. Participants who spent ≥ 1 h daily in production areas had twice the odds of any spirometric abnormality (OR 2.3; 95% CI 1.1 to 5.3) and three times the odds of low diffusing capacity (OR 2.8; 95% CI 0.9 to 9.4) than other participants. Mean spirometric parameters were significantly lower in those with tenure ≥ 7 years and those who spent ≥ 1 h daily in production. Mean diffusing capacity parameters were significantly lower in those with tenure ≥ 7 years. Differences in symptoms and lung function could not be explained by age, smoking status or employment at another flavouring plant., Conclusions: Symptoms and lung function findings were consistent with undiagnosed or subclinical obliterative bronchiolitis and associated with workplace exposures. Further efforts to lower exposures to flavouring chemicals, including diacetyl substitutes, are warranted., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Background: Factors that influence exposure to silver particles from the use of textiles are not well understood., Objectives: The aim of this study was to evaluate the influence of product treatment and physiological factors on silver release from two textiles., Methods: Atomic and absorbance spectroscopy, electron microscopy, and dynamic light scattering (DLS) were applied to characterize the chemical and physical properties of the textiles and evaluate silver release in artificial sweat and saliva under varying physiological conditions. One textile had silver incorporated into fiber threads (masterbatch process) and the other had silver nanoparticles coated on fiber surfaces (finishing process)., Results: Several complementary and confirmatory analytical techniques (spectroscopy, microscopy, etc.) were required to properly assess silver release. Silver released into artificial sweat or saliva was primarily in ionic form. In a simulated "use" and laundering experiment, the total cumulative amount of silver ion released was greater for the finishing process textile (0·51±0·04%) than the masterbatch process textile (0·21±0·01%); P<0·01., Conclusions: We found that the process (masterbatch vs finishing) used to treat textile fibers was a more influential exposure factor than physiological properties of artificial sweat or saliva.

Laboratory measurements of ultrafine titanium dioxide (TiO2) particulate matter loaded on filters were made using three field portable methods (X-ray fluorescence (XRF), laser-induced breakdown spectroscopy (LIBS), and Fourier-transform infrared (FTIR) spectroscopy) to assess their potential for determining end-of-shift exposure. Ultrafine TiO2 particles were aerosolized and collected onto 37 mm polycarbonate track-etched (PCTE) filters in the range of 3 to 578 μg titanium (Ti). Limit of detection (LOD), limit of quantification (LOQ), and calibration fit were determined for each measurement method. The LOD's were 11.8, 0.032, and 108 μg Ti per filter, for XRF, LIBS, and FTIR, respectively and the LOQ's were 39.2, 0.11, and 361 μg Ti per filter, respectively. The XRF calibration curve was linear over the widest dynamic range, up to the maximum loading tested (578 μg Ti per filter). LIBS was more sensitive but, due to the sample preparation method, the highest loaded filter measurable was 252 μg Ti per filter. XRF and LIBS had good predictability measured by regressing the predicted mass to the gravimetric mass on the filter. XRF and LIBS produced overestimations of 4% and 2%, respectively, with coefficients of determination (R(2)) of 0.995 and 0.998. FTIR measurements were less dependable due to interference from the PCTE filter media and overestimated mass by 2% with an R(2) of 0.831.

Unlabelled: The performance of two direct-reading organic vapor monitors (monitors) when calibrated at different environmental conditions was compared with charcoal tube results. Three MIRAN SapphIRe portable ambient air analyzers (SAP) and three Century portable toxic vapor analyzers (TVAs) were evaluated. Prior to sampling, the monitors were calibrated per the manufacturer's instructions using methane for the TVA flame ionization detector (FID) and isobutylene for the photoionization detector (PID), whereas the SapphIRe instruments were zeroed and the instrument's manufacturer-supplied library was used. For the first series of tests ("Part 1--Same condition"), the monitors were calibrated under the same environmental conditions as those present during sampling. They were then challenged with four cyclohexane concentrations (30, 150, 300, and 475 ppm) under two extreme environmental conditions: 5 degrees C and 30% relative humidity (RH) (same/cold) and 38 degrees C and 90% RH (same/hot). For the second series of tests ("Part 2--Different condition"), the monitors were calibrated at approximately normal indoor environmental conditions (21 degrees C and 50% RH) and sampled at extreme environmental conditions (different/cold and different/hot). The monitor readings from the two methods were compared with the actual cyclohexane concentration determined from charcoal tubes using ratios and root mean square errors. A number of monitor failures, both below detection limit values in the presence of a known challenge concentration and erroneously high measurements, occurred in each part: same condition 20.7% (149/720) and different condition 42.4% (305/ 720), with a majority of the failures (> 78%) during the hot and humid conditions. All monitors performed best at the same/cold, followed by the same/hot, in terms of closeness to the reference standard method and low within-monitor variability. The ranked choice of monitors for same/cold is PID > SAP > FID; for different/cold FID > PID > SAP; for same/hot SAP > PID > FID; and for different/hot PID > SAP (FID not included due to 100% failure rate)., Implications: Direct-reading organic vapor monitors are used for assessing the concentrations of volatile organic compounds in the air at varying environmental conditions. Typical calibration is performed at laboratory temperature and pressure. The monitors may be used in atmospheres that differ from that during calibration. An understanding of the effect of calibration environment on monitor performance may provide valuable information on the reliability and appropriateness of certain monitor types for industrial hygienists, emergency responders, and exposure assessment practitioners. Results of the study indicate monitor calibration should be performed at the same environmental conditions as sampling.

Miners are exposed to silica-bearing dust which can lead to silicosis, a potentially fatal lung disease. Currently, airborne silica is measured by collecting filter samples and sending them to a laboratory for analysis. Since this may take weeks, a field method is needed to inform decisions aimed at reducing exposures. This study investigates a field-portable Fourier transform infrared (FTIR) method for end-of-shift (EOS) measurement of silica on filter samples. Since the method entails localized analyses, spatial uniformity of dust deposition can affect accuracy and repeatability. The study, therefore, assesses the influence of radial deposition uniformity on the accuracy of the method. Using laboratory-generated Minusil and coal dusts and three different types of sampling systems, multiple sets of filter samples were prepared. All samples were collected in pairs to create parallel sets for training and validation. Silica was measured by FTIR at nine locations across the face of each filter and the data analyzed using a multiple regression analysis technique that compared various models for predicting silica mass on the filters using different numbers of "analysis shots." It was shown that deposition uniformity is independent of particle type (kaolin vs. silica), which suggests the role of aerodynamic separation is negligible. Results also reflected the correlation between the location and number of shots versus the predictive accuracy of the models. The coefficient of variation (CV) for the models when predicting mass of validation samples was 4%-51% depending on the number of points analyzed and the type of sampler used, which affected the uniformity of radial deposition on the filters. It was shown that using a single shot at the center of the filter yielded predictivity adequate for a field method, (93% return, CV approximately 15%) for samples collected with 3-piece cassettes.

Healthcare settings present a challenging environment for assessing low-level concentrations of specific volatile organic compounds (VOCs) in the presence of high background concentrations of alcohol from the use of hand sanitizers and surface disinfectants. The purposes of this laboratory-based project were to develop and validate a sampling and analysis methodology for quantifying low-level VOC concentrations as well as high-level alcohol concentrations found together in healthcare settings. Sampling was conducted using evacuated canisters lined with fused silica. Gas chromatography/mass spectrometry analysis was performed using preconcentration (for ppb levels) and loop injection (for ppm levels). For a select list of 14 VOCs, bias, precision, and accuracy of both the preconcentration and loop injection methods were evaluated, as was analyte stability in evacuated canisters over 30 days. Using the preconcentration (ppb-level) method, all validation criteria were met for 13 of the 14 target analytes-ethanol, acetone, methylene chloride, hexane, chloroform, benzene, methyl methacrylate, toluene, ethylbenzene, m,p-xylene, o-xylene, alpha-pinene, and limonene. Using the loop injection (ppm-level) method, all validation criteria were met for each analyte. At ppm levels, alpha-pinene and limonene remained stable over 21 days, while the rest of the analytes were stable for 30 days. All analytes remained stable over 30 days at ppb levels. This sampling and analysis approach is a viable (i.e., accurate and stable) methodology that will enable development of VOC profiles for mixed exposures experienced by healthcare workers., (This journal is © The Royal Society of Chemistry 2012)

The National Institute for Occupational Safety and Health (NIOSH) research on direct-reading instruments (DRIs) needed an instantaneous sampling method to provide independent confirmation of the concentrations of chemical warfare agent (CWA) simulants. It was determined that evacuated canisters would be the method of choice. There is no method specifically validated for volatile organic compounds (VOCs) in the NIOSH Manual of Analytical Methods. The purpose of this study was to validate an evacuated canister method for sampling seven specific VOCs that can be used as a simulant for CWA agents (cyclohexane) or influence the DRI measurement of CWA agents (acetone, chloroform, methylene chloride, methyl ethyl ketone, hexane, and carbon tetrachloride [CCl4]). The method used 6-L evacuated stainless-steel fused silica-lined canisters to sample the atmosphere containing VOCs. The contents of the canisters were then introduced into an autosampler/preconcentrator using a microscale purge and trap (MPT) method. The MPT method trapped and concentrated the VOCs in the air sample and removed most of the carbon dioxide and water vapor. After preconcentration, the samples were analyzed using a gas chromatograph with a mass selective detector. The method was tested, evaluated, and validated using the NIOSH recommended guidelines. The evaluation consisted of determining the optimum concentration range for the method; the sample stability over 30 days; and the accuracy, precision, and bias of the method. This method meets the NIOSH guidelines for six of the seven compounds (excluding acetone) tested in the range of 2.3-50 parts per billion (ppb), making it suitable for sampling of these VOCs at the ppb level.

A limitation of most artificial sweat formulations used for in vitro assessment of chemical release from materials in contact with skin have little biological relevance to human sweat. The purposes of this paper are to provide guidance for preparation of a novel artificial sweat with chemical constituents at concentrations that match human sweat and to characterize chemical stability. The artificial sweat was characterized under conditions of use (with and without sebum at 36 degrees C) and storage (without sebum at -4, 4, and 23 degrees C) over 28 days by gas chromatography-mass spectroscopy, high-performance liquid chromatography, enzymatic assay kits, and ion-selective electrodes. Seven indicator constituents were tracked: sodium, chloride, glucose, lactic acid, urea, pantothenic acid, and alanine. With or without sebum at 36 degrees C, the sweat solvent was chemically stable for 14 days. Storage by refrigeration at 4 degrees C retained the chemical integrity of the solvent longest. Based on these results, the solvent should be used within 14 days of preparation. The artificial sweat model presented herein is most similar to human sweat and has applications as a dissolution solvent, donor solution in diffusion cells, or vehicle for patch testing. This sweat model may aid researchers in understanding potential release and percutaneous absorption of chemicals in contact with human skin surface liquids., (Published by Elsevier Ltd.)

Identification of mold growth based on microbial volatile organic compounds (MVOCs) may be a viable alternative to current bioaerosol assessment methodologies. A feed-forward back propagation (FFBP) artificial neural network (ANN) was developed to correlate MVOCs with bioaerosol levels in built environments. A cross-validation MATLAB script was developed to train the ANN and produce model results. Entech Bottle-Vacs were used to collect chemical grab samples at 10 locations in northern NY during 17 sampling periods from July 2006 to August 2007. Bioaerosol samples were collected concurrently with chemical samples. An Anderson N6 impactor was used in conjunction with malt extract agar and dichloran glycerol 18 to collect viable mold samples. Non-viable samples were collected with Air-O-Cell cassettes. Chemical samples and bioaerosol samples were used as model inputs and model targets, respectively. Previous researchers have suggested the use of MVOCs as indicators of mold growth without the use of a pattern recognition program limiting their success. The current proposed strategy implements a pattern recognition program making it instrumental for field applications. This paper demonstrates that FFBP ANN may be used in conjunction with chemical sampling in built environments to predict the presence of mold growth., (2010 Elsevier B.V. All rights reserved.)

Measuring trace levels of volatile organic compounds (VOCs) in indoor environments is important for the characterization of occupant exposures. The ability to quickly collect air samples at relatively low costs per sample can increase the number of samples that can be collected and thus improve the overall assessment of potential exposures. The specific goal of this paper is to evaluate the accuracy and precision of evacuated glass bottle air samplers (Entech Bottle-Vacs) to collect representative VOC samples at part-per-billion concentrations in indoor environments. Laboratory generated data are also included to validate the precision and accuracy of the method. Multiple Bottle-Vacs in 10 residences in northern New York over 18 different sampling periods were used to collect whole-air VOC samples. Percent relative standard deviations ranged from 1.2 to 20.3% with a median of 8.8% for the 21 compounds analyzed in each Bottle-Vac. Two sampling techniques were used: around the valve (ATV) and through the valve (TTV). Linear regressions of ATV and TTV sample collection into the Bottle-Vacs show that these two sampling techniques are reproducible. Paired t test results show that ATV sampling is more reproducible than TTV; ATV paired samples were statistically the same 100% of the time whereas TTV paired samples were statistically the same 76.9% of the time. ATV sampling of low-level VOCs in indoor built environments is a reproducible chemical sampling technique that could be used by building occupants as a quick and inexpensive means of area sampling.