扩散法被动式挥发性有机化合物个体监测器的研制

研制了一种以单层活性炭颗粒作为吸收介质的被动式挥发性有机化合物个体监测器。空气中挥发性有机化合物依据分子扩散原理传质到采样器中，并吸附到活性炭上。采样后，取出活性炭吸附层，用二硫化碳洗脱，再用气相色谱法定性和定量。对监测器进行了实验室性能评价和现场验证。结果表明，采样器在风速２０～１５０ｃｍ／ｓ，相对温度１０％～８０％，温度－１０～３５℃范围内使用，采样速率分别为６０ｍｌ／ｍｉｎ（苯）、５４ｍｌ／ｍｉｎ（甲苯）、５４ｍｌ／ｍｉｎ（氯仿）和４９ｍｌ／ｍｉｎ（对－二甲苯），相对标准差小于５％。在现场与有泵活性炭管采样相比较，本个体监测器测定空气中挥发性有机化合物的总不确定度分别为１２％（苯）、１２％（甲苯）、２６％（对－二甲苯）和１６％（氯仿），可适用于室内空气污染和个体接触量的监测。     

Charcoal sampling method for determining the concentration of styrene in air.

The vapors of styrene (vinylbenzene) were trapped on charcoal in a glass tube. Air from the worker's breathing zone was sucked through the tube by a battery-operated, modified, MSA personal sampling pump. The sampler and pumping system were worn by the worker. The styrene were eluted with dimethyl formamide and estimated by gas chromatography. The range and sensitivity of the method when sampling with a flow rate of 0.2 1/min during 1 h were 5 to 1,500 ppm, and during 4 h they were 2 to 400 ppm. The recovery (accuracy) was over 90%. The precision for the method, in terms of relative standard deviation, was 8.4%.     

Application of the personal aeroallergen sampler to assess personal exposures to Japanese cedar and cypress pollens

We have recently developed the Personal Aeroallergen Sampler (PAAS), a passive sampler for aeroallergens. In the present study, the applicability of the PAAS for personal exposure assessments of cedar and cypress pollens was investigated by comparing with existing reference samplers. To investigate the usability of the PAAS as a personal sampler for the airborne pollens, it was compared with the Institute of Occupational Medicine (IOM) sampler, a traditionally used active personal sampler. Overall, the result showed a good correlation between the two methods, that is, R(2)=0.8082, suggesting the usability of the PAAS for the personal pollen samplings. The ratio of the pollen numbers collected by the PAAS to the IOM sampler was approximately 30%, which was consistent with our previous study investigating ambient dust particles. Meanwhile, the comparability of the PAAS to the Durham sampler, the most widely used stationary pollen trap, was also assured. Furthermore, we exemplified the seasonal peak of the personal pollen exposures was not necessarily reflected by the outdoor concentrations, indicating insufficiency of the stationary outdoor monitoring to represent the personal pollen exposures. The PAAS, a simple passive method, could be used in future field studies to elucidate the detailed mechanisms of allergic airway diseases such as cedar pollinosis.     

用二氯甲烷等解吸活性炭管中苯及苯系物效果的研究

目的建立用低毒的有机溶剂代替二硫化碳解吸活性炭管中苯、甲苯、二甲苯等苯系物的方法。方法分别用三氯甲烷、二氯甲烷、1,2-二氯乙烷三种有机化合物为溶剂,解吸已加标的活性碳管中三苯并测定其回收率。结果除1,2-二氯乙烷外,三氯甲烷、二氯甲烷对苯及苯系物的解吸率均大于75%,且精密度令人满意。结论本法中的三氯甲烷、二氯甲烷完全可取代二硫化碳作为苯系物的解吸剂,且其相对低毒环保,可以用于日常监测。     

Estimation of personal exposure to tobacco smoke with a newly developed nicotine personal monitor

To evaluate the actual level of exposure of nonsmokers to tobacco smoke in their living environments, a convenient personal monitor of nicotine specific for tobacco smoke has been developed. The nicotine personal monitor consists of a sampler tube containing 450 mg of Uniport-S coated with silicon OV-17 and a portable sampling pump with a mechanical counter for obtaining total sampling volume. Using the personal monitor attached to a nonsmoker, ambient nicotine was collected in the sampler tube by drawing environmental air at a constant flow rate for a maximum period of 8 hr. The collected nicotine was desorbed by heating and directly transferred onto a GC column with a carrier gas. The amounts of nicotine inhaled by passive smoking in various living environments were estimated to be in the range of 0.9-40 micrograms/hr. These levels are equivalent to those from the active smoking of about 0.001-0.044 ordinary cigarettes in 1 hr.     

Initial field evaluation of the Harvard active ozone sampler for personal ozone monitoring.

Assessing personal exposure to ozone has only been feasible recently with the introduction of passive ozone samplers. These devices are easy to use, but changes in air velocity across their collection surfaces can affect performance. The Harvard active ozone sampler (AS) was developed in response to problems with the passive methods. This active sampler has been tested extensively as a microenvironmental sampler. To test for personal sampling, 40 children attending summer day-camp in Riverside, California wore the active ozone sampler for approximately 2.6 h on July 19 and 21, 1994, when ozone concentrations were about 100 ppb and 140 ppb, respectively. The children spent 94-100% of the sampling period outside, staying within a well-defined area while participating in normal camp activities. Ambient ozone concentrations across this area were monitored by two UV photometric ozone monitors. The active sampler was worn in a small backpack that was also equipped with a passive ozone sampler. Device precision, reported as the percent difference between duplicate pairs of samplers, was +/- 3.7% and +/- 4.2% for the active and passive samplers, respectively. The active sampler measured, on average, 94.5 +/- 8.2% of the ambient ozone while the passive samplers measured, on average, 124.5 +/- 18.8%. The samplers were worn successfully for the entire sampling period by all participating children.     

Development and validation of personal monitoring methods for low levels of acrylonitrile in workplace atmosphere: I. Test atmosphere generation and solvent desorption methods

The purpose of this study was to optimize monitoring methods and to investigate new technology for the determination of low levels of acrylonitrile (0.05 to 5 ppm) in workplace atmospheres. In the first phase of the study, a dynamic atmosphere generation system was developed to produce low levels of acrylonitrile in simulated workplace atmospheres. Various potential sorbents were investigated in the second phase, and the candidate methods were compared in a laboratory validation study over a concentration range from 0.05 to 5 ppm acrylonitrile in the presence of potential interferences and under relative humidity conditions from 30% to 95% RH. A collection tube containing 600 mg Pittsburgh coconut base charcoal was found to be the optimum tube for sampling for a full 8-hr shift. No breakthrough was observed over the concentrations and humidities tested. The recovery was 91.3% with a total relative precision of +/- 21% over the test range, and the recovery was not affected by storage for up to five weeks.     

低浓度挥发性有机化合物被动式个体采样器的研究

研制了扩散式挥发性有机化合物（ＶＯＣｓ）个体采样器,适用于对环境空气中和非职业性个体接触ＶＯＣｓ的监测。在风速１０～２６０ｃｍ／ｓ,相对湿度为３０％～８０％,温度为１０～３０℃的范围内使用,采样速率分别为苯：２５．７４ｍｌ／ｍｉｎ,甲苯：２５．１６ｍｌ／ｍｉｎ,四氯乙烯：２５．８５ｍｌ／ｍｉｎ,对－二甲苯：８．１６ｍｌ／ｍｉｎ,苯乙烯：６．４７ｍｌ／ｍｉｎ。与主动式活性炭纤维（ＡＣＦ）管采样法比较,本个体采样器测定空气中靶ＶＯＣｓ的总不确定度均在±２５％以内。     

徽章式被动式采样器测定空气中甲醛的研究

目的研制测定空气中甲醛的被动式个体采样器。方法根据费克第一扩散定律设计新型被动式个体采样器,并对采样器的性能指标进行评价。结果在温度为10～40℃,湿度为20%～40%,风速为50～600 cm/s的范围内,被动式采样器测定空气中甲醛采样流量为104.05 ml/min,最大吸附容量为0.275 1 mg,最短采样时间为30 min,用前稳定性30 d,样品稳定性≥14 d,精密度RSD为5.34%。结论研制的个体采样器可以作为一种测定空气中甲醛的新型采样仪器。     

Performance assessment of a passive sampler in industrial atmospheres

In this work we investigate the performances of a passive sampler (GABIE badge) in industrial atmospheres, in accordance with the general specifications of the EN 838 standard. The field experiment was carried out in a paint-manufacturing factory producing a large number of pollutants at the workplaces. A comparison was performed between the results obtained by passive sampling and the conventional tube/pump method (reference method) on nine solvents usually encountered in the different workshops: n-butanol, isobutanol, toluene, ethylbenzene, m-xylene, methylisobutylketone, methylethylketone (MEK), ethyl acetate, butyl acetate. Results were compared by use of the distribution of the relative difference between badge "passive sampling" and tube "active sampling" results (with the latter considered as the reference method). In general, results revealed good agreement between passive and active sampling (except in the case of MEK) and confirmed the accuracy of sampling rates determined for the GABIE sampler. Bias was generally low and variability could be considered to be satisfactory (generally < 20% with a maximum of 30% for ethylbenzene). For MEK, strong bias was noted together with probable underestimation of the tube results. Additional results lead us to suggest that this phenomenon could be due to poor desorption of the SKC tubes by carbon disulphide (CS2); (quantitative recovery for MEK is in fact possible using other desorption solvents).     

被动式有机蒸气采样器的研制

此采样器,可采集空气中六种有机蒸气,它无采样泵。体积小,重量轻,既可采集个体在接触时间内的累积量也可采集定点样品。采样后取出采样介质,加二硫化碳解吸,用气相色谱法测定。对准确度、精密度、吸附容量、样品储存期、风速影响、湿度影响及干扰等进行了实验观察。六种蒸气全过程的准确度为±7.7～±13.6%,符合NIOSH的推荐标准。合并变异系数为 2.7～5.3%。文中还报告了现场测定结果。     

Field evaluation of a passive sampler for assessing 2-ethoxyethyl acetate exposures

This paper presents a field evaluation of a passive badge for measuring 2-ethoxyethyl acetate (2-EEAc) in a humid working environment. Forty-eight pairs of side-by-side active/passive 8-h full-shift personal samples were collected to evaluate the performance of a passive badge for monitoring 2-EEAc with the co-exposure of toluene and methyl iso-butyl ketone (MIBK) in a warm and humid workplace. Sixteen pairs of side-by-side passive badges, active charcoal tubes, and active charcoal tube with drying tube samples were also compared to evaluate the humidity effect in sampling. No statistical difference was found between the passive and active samples in assessing 2-EEAc. Linear regression showed the correlation to be high (r=0.987, slope=1.018, n=48) over the range 0.42-41.5 ppm. The mean concentration difference was 0.53 ppm and the mean relative error was 5.39%. Close correlation was also found between passive and active samples for assessing both toluene (r=0.949, slope=0.918, n=16), and MIBK (r=0.943, slope=1.098, n=16). Similar high correlation (r>0.962, n=16) was found among passive badges, active charcoal tubes, and active charcoal tube with drying tube samples. The humidity effect and the interference of co-exposure of polar and non-polar solvents were insignificant at a low sampling rate (26.6 ml/min) in assessing 2-EEAc exposures. The use of the passive samplers produces comparable findings to that of active sampling.     

Comparison between active (pumped) and passive (diffusive) sampling methods for formaldehyde in pathology and histology laboratories

This study was to determine occupational exposures to formaldehyde and to compare concentrations of formaldehyde obtained by active and passive sampling methods. In one pathology and one histology laboratories, exposure measurements were collected with sets of active air samplers (Supelco LpDNPH tubes) and passive badges (ChemDisk Aldehyde Monitor 571). Sixty-six sample pairs (49 personal and 17 area) were collected and analyzed by NIOSH NMAM 2016 for active samples and OSHA Method 1007 (using the manufacturer's updated uptake rate) for passive samples. All active and passive 8-hr time-weighted average (TWA) measurements showed compliance with the OSHA permissible exposure limit (PEL-0.75 ppm) except for one passive measurement, whereas 78% for the active and 88% for the passive samples exceeded the NIOSH recommended exposure limit (REL-0.016 ppm). Overall, 73% of the passive samples showed higher concentrations than the active samples and a statistical test indicated disagreement between two methods for all data and for data without outliers. The OSHA Method cautions that passive samplers should not be used for sampling situations involving formalin solutions because of low concentration estimates in the presence of reaction products of formaldehyde and methanol (a formalin additive). However, this situation was not observed, perhaps because the formalin solutions used in these laboratories included much less methanol (3%) than those tested in the OSHA Method (up to 15%). The passive samplers in general overestimated concentrations compared to the active method, which is prudent for demonstrating compliance with an occupational exposure limit, but occasional large differences may be a result of collecting aerosolized droplets or splashes on the face of the samplers. In the situations examined in this study the passive sampler generally produces higher results than the active sampler so that a body of results from passive samplers demonstrating compliance with the OSHA PEL would be a valid conclusion. However, individual passive samples can show lower results than a paired active sampler so that a single result should be treated with caution.     

A sampling and analytical method for vinylidene chloride in air

A sampling and analytical method for the determination of vinylidene chloride in air is presented. Vinylidene chloride can be quantitatively trapped on charcoal over a wide range of concentrations. The collected vapors are desorbed with carbon disulfide and analyzed by gas chromatography utilizing a flame ionization detector. The analytical column is packed with Durapak OPN. The lower limit for the method is approximately 7 micrograms of vinylidene chloride per sampling tube. The breakthrough volume was found to be dependent upon the concentration sampled and the relative humidity of the air sampled. The overall precision of the analytical method is 5% (relative standard deviation).     

Passive sampling and head space analysis for quantitative determination of nitrous oxide exposure.

A new technique has been developed for determining the time-weighted average personal exposure to nitrous oxide gas. Nitrous oxide gas is passively collected on a molecular sieve contained in a glass tube and partially desorbed in a vial until solid-gas equilibrium at 100 degrees C. Next, nitrous oxide concentration in the head space air in the vial is measured with a gas chromatograph equipped with an electron capture detector. This study shows that nitrous oxide concentration in the head space is proportional to both the nitrous oxide concentration in the test atmosphere and the sampling time up to 1600 ppm/hr. The coefficient of variance is less than 10%. The performance of the sampler is not affected by water vapor or carbon dioxide in the atmosphere nor by air currents. The sampler can be stored for 2 weeks at either 4 or 25 degrees C. Because the passive sampler is small and light, it can be used to determine exposure to nitrous oxide during surgical operations.     

某型号个体采样器采样过程中流量变化规律的探讨

目的 探讨某型号个体采样器采样过程中流量变化规律.方法 分别测量不同型号、不同规格炭管管口水平放置、管口向上竖直放置和管口向下竖直放置3种情况下,不同采样时间的流量,比较流量的变化规律.结果 无论何种炭管及如何放置,采样流量均随采样时间的增加而增加;炭管管口向下放置时,流量随时间的增加速度稍高于其他两种情况;在炭管不同...     

Carbon disulfide exposure assessment in a Chinese viscose filament plant

Carbon disulfide is a well-known occupational hazard in the viscose industry, and studies have shown considerable health effects when workers are exposed to high concentrations of this reagent. At exposure levels below the TLV-TWA(31 mg/m³), findings remain contradictory, probably due to deficient exposure data. The present study tries to identify the occupational hazards and thoroughly assess the exposure levels in a Chinese viscose rayon plant.

Methods: An industrial hygienic field survey and a sampling campaign were carried out, including multi-gas monitoring, on-line measurements, and stationary assessment in the spinning hall as well as personal exposure sampling for spinners (by charcoal tube absorbing and GC-FPD analysis). All data was introduced into Foxpro database, and analyzed by Epi info (6.04) and SPSS.

Results: On-line measurement showed that the geometric mean (GM) of carbon disulfide exposure amounted to 12.73 mg/m³ in 'exposure' and 0.08 mg/m³ in 'non-exposure' worksites. These concentrations in the air were related to the subject's activities showing the highest levels when they had to open the shield windows of the spinning machines. Stationary exposure measurements of carbon disulfide in the spinning hall amounted to 23.29 mg/m³ GM (range 5.8-97.94 mg/m³). Personal exposure of spinners was about 17.3 mg/m³GM. Comparing these methods, the personal exposure sampling could exactly express the exposure levels of the worker's contacting situation. The on-line measurement by multi-gas monitor might also be recommended to the factory as it has its own advantages of rapid and independent assessment, but it under-estimates the exposure level.     

Evaluation of concurrent personal measurements of acrylonitrile using different sampling techniques

In a retrospective assessment of employee exposure to acrylonitrile (AN) for an epidemiological study, investigators from the National Cancer Institute (NCI) and the National Institute for Occupational Safety and Health (NIOSH) evaluated the feasibility of using historic acrylonitrile air samples without modification. The evaluation discussed here was to determine whether the air sampling results across plants were comparable. During site visits to each plant conducted between 1984 and 1986, study investigators collected personal air samples for four days on approximately ten jobs per day. During these visits, IHs at seven of the eight plants also collected personal samples to compare their sample values to the study-collected sample values. Each plant's IH collected these concurrent measurements for their own use and independent of the IHs at the other plants. The plant IHs had no common sampling protocol but, rather, used professional judgment in deciding sampling logistics for their concurrent measurement. In addition, each plant IH used a different laboratory to analyze samples (the study industrial hygienists used one laboratory). Three sampling methods were used by plant industrial hygienists to collect concurrent measurements: charcoal tubes, passive monitors, and porous polymer tubes. The study investigators only used charcoal tubes. Two hundred and sixty four (264) pairs of concurrent measurements were collected. To assess the +/- comparability of the data sets, paired-observation tests were used. The two sets of charcoal tubes were found to compare favorably with each other. The study's charcoal tubes were 1.2 times higher than results from plant passive monitors. No correlation was found between the study's charcoal tube results and plant porous polymer tube results, although the means for 34 pairs of samples were equivalent. As a result of this evaluation, the investigators decided that no adjustments would be made to the plant measurements. This type of evaluation should be considered when using measurement data in multisite epidemiological studies.     

Laboratory evaluation of pressure differential-based respirable dust detector tube

Assessment of exposure to occupational dusts is a first step in reducing exposures to harmful dust concentrations. A new type of respirable dust sampler was developed and compared side-by-side to personal gravimetric samplers in the laboratory. The new sampler correlates filter back pressure with mass accumulation to provide mid-shift- and end-of-shift determinations of cumulative exposure. The sampler uses a small low flow rate pump to draw dust through a small detector tube that contains a porous urethane foam respirable classification section and glass fiber filter that collects respirable dust. Six different coal dusts were aerosolized in a laboratory dust chamber and a total of 119 triplicate observations were obtained. For individual coal types, the correlation coefficients were between 0.87 and 0.97. The precision of the two methods was similar, with the percent relative standard deviation of the personal samplers of 12 percent and the new detector method of 14 percent. For all coal types tested th data were best described by a power function where delta P = 1.43 mass (0.85), with a correlation coefficient of 0.73. The method becomes more accurate at higher dust loadings such that all laboratory data with mass loadings greater than an equivalent concentration of 2 mg/m3 fall within +/- 25 percent of the power function. Assessment of the method under field conditions is in progress.     

Laboratory and field validation of a JXC charcoal sampling and analytical method for monitoring short-term exposures to ethylene oxide

A sampling and analytical method for the measurement of ethylene oxide (EtO) short-term exposure limits (STEL) was validated under both laboratory and field conditions. These studies were designed to examine the method against both the Occupational Safety and Health Administration (OSHA) EtO permissible exposure limit (PEL) method requirements and the National Institute for Occupational Safety and Health (NIOSH) industrial hygiene method validation criteria. The method's pooled accuracy was shown to be within both OSHA requirements and NIOSH guidelines. The EtO was collected on a JXC charcoal tube at a sample flow rate of 100 mL/min for 15 min. The samples were shipped on dry ice and were stored in a freezer until analyzed. The EtO was desorbed by carbon disulfide and the eluent was analyzed by gas chromatography with flame ionization detection (GC-FID). The desorption efficiency of EtO from JXC charcoal tubes was determined to be 84% over the 15-min time-weighted average concentrations: 2.5, 5.0 and 10 ppm EtO. The method limit of detection was determined to be 1.0 ppm. The coefficient of variation of the combined sampling and analytical method was 5.7%. A -7% method bias was calculated. Field validation of the method included data from a portable GC-FID for the determination of method bias. Results of the field validation study over the concentration range of 2.4 ppm to 19.9 ppm generated a field precision of 8.1% with an absolute bias of 3.9%. The method accuracy was determined to be +/- 20%.(ABSTRACT TRUNCATED AT 250 WORDS)