Impinger Sampling Research Articles

Polyurethane (PU)‐foam‐plug/impinger sampling train for monitoring of PCDD/F‐emissions from incinerators and other emission sources

A versatile polyurethane‐foam (PUF)/impinger sampling train (ST) is presented, which allows emission monitoring of a variety of sources, such as stacks, furnaces, scrubbers or smoke gases from fire simulation tests. Flow rates between 0.5 m3/hr and 20 m3/hr can be achieved combining the adequate size of ST‐apparatus. This type of PUF/Impg.‐ST has been successfully tested, compared with other STs and is used for emission monitoring as well as for measurements in the different stages of incinerators ecc, for workplace monitoring, process optimization and research, up to gas temperatures of 1200°C and with high dust loads. Depending on the apparatus and flow rate setting detection limits down to 1 pg/m3 PHDDs/Fs can be attained. Data on sampling and stack measurements as well as the detailed procedure for sample preparation and clean up are given.

Reproductive Seasonality, Distribution, and Abundance of Prionotus carolinus and P. evolans (Pisces: Triglidae) in the New York Bight

The reproductive seasonality, distribution, and abundance of two sympatric searobins, Prionotus carolinus (Linnaeus) and P. evolans (Linnaeus), were investigated using multiple gears (plankton nets, seines, trawls, and power plant impingement samples) in several New Jersey estuaries and across the continental shelf of the New York Bight. Reproduction occurred from May to October and peaked in July or August based on collections of eggs ( Prionotus spp.) near Little Egg Inlet, during 1972-75. The larvae were present July-October and abundance peaked in September. Eggs and larvae were more abundant at inner continental shelf stations compared to estuarine stations. Juvenile (<100 mm standard length) P. carolinus were primarily found at inner shelf habitats from September to December, but they were also collected in much colder months (i.e. February-June). Juvenile P. evolans were captured in both estuarine and inner shelf habitats from July to December. Prionotus carolinus was generally more numerous and more frequently collected in trawls compared to P. evolans, but diel period, season, and habitat all affected measured abundance. Catches for both species were higher and more frequent at night. Both species were collected from May to November, but P. carolinus arrived earlier to (and emigrated sooner from) coastal habitats than P. evolans. Each species was also distributed differentially between estuarine and continental shelf habitats, although they frequently occurred together. A canonical discrimination analysis showed that P. evolans was found in seasonally warmer, less oxygenated, and more turbid habitats than P. carolinus. In addition, P. carolinus was found scattered near the edge of the continental shelf during winter (i.e. January-March) when P. evolans was not collected in the New York Bight. Temperature, in particular, helps explain the observed interspecific differences in seasonal distribution at a small scale (i.e. in the estuary) as well as at a large scale (i.e. across the continental shelf).

Ion chromatographic determination of carboxylic acids in air with on-line liquid membrane pretreatment

A method for the determination of low-molecular-mass carboxylic acids in air is reported. The method is based on impinger sampling in sodium hydroxide, selective enrichment across a liquid membrane and determination by ion-exclusion chromatography. The membrane enrichment is carried out in an automated continuous-flow system coupled to the chromatographic column. By impregnation of the membrane with 10% tri- n-octylphosphine oxide in di- n-hexyl ether, extraction efficiencies in the range 30–100% for C 1–C 4, carboxylic acids were achieved. Formic and acetic acid were measured in the range 17–300 nmol/m 3 and some other carboxylic acids were detected in air samples taken in southern Sweden.

Determination of aliphatic amines in air by membrane enrichment directly coupled to a gas chromatograph

A method is described for the determination of shortchain aliphatic amines in ambient air based on impinger sampling in dilute H2SO4, selective enrichment across a PTFE gas membrane and quantification by gas chromatography. The enrichment step is carried out in a flow system directly connected to the chromatograph. The separation is performed on a packed column with nitrogen selective detection. The enrichment per sample volume was in the range 7.3 to 8.2 mL−1 for C1−C6 amines. Detection limits were ca 3–10 nM with enrichment of a 2.9 mL liquid sample. After impinger sampling of 5 m3 air in 10 mL absorption solution, this corresponds, to 0.4–0.8 ng/m3 (ca 0.2–0.5 ppt by volume) in air.

A Comparison of Air Sampling Methods for Airborne Silica in the Diatomaceous Earth Industry

Abstract The purpose of this study was to derive empirical quantitative relationships from linear regression equations between standard impinger, total mass, and respirable mass sampling methods for silica dust in the diatomaceous earth industry. Dust from one diatomaceous earth processing plant was sampled simultaneously by all three sampling methods. Two areas within the plant were sampled: one area included only main flux-calcined product; the other included only bag-house flux-calcined product. The baghouse product contains a much higher percentage of small-sized particles than the main product. Results from 61 clusters of the three sampling devices indicate that the particle size distribution of the dust varies with the particle size distribution of the parent product handled in that area. Since the respirable mass method is dependent on the particle size distribution of the dust, separate relationships were derived for main product and baghouse product dust. For bag-house product dust, the relations...

Practical aspects of sampling for organic dusts and microorganisms

Air sampling for organic dusts and microorganisms was carried out in silos when moldy silage was discarded through the discharge chute. Concentrations of respirable dust and airborne viable microorganisms exceeded 20 mg/m3 and 1 x 10(9)/m3, respectively, when dry silage was removed from silos. Much lower concentrations of dust and microorganisms were present when wet silage was discarded. Impinger and filter cassette samplers were equally effective in collecting the hardy spores present in silage dusts.

Determination of acrylonitrile in stationary source emissions by impinger sampling and gas chromatography with nitrogen-phosphorus detection

Les methodes d'echantillonnage et d'analyse ont ete evaluees a l'aide de tests en laboratoire et sur le terrain. Une fidelite de 4,6% et une precision de 3,3% ont ete atteintes

2,4-Dinitrophenylhydrazine-coated silica gel cartridge method for determination of formaldehyde in air: identification of an ozone interference

Two versions of the 2,4-dinitrophenylhydrazine method, a coated silica gel cartridge (solid) and acetonitrile impinger (solvent based), were used simultaneously to sample varied concentrations of ozone (0-770 ppb) and formaldehyde (20-140 ppb). Ozone was found to be a negative interference in the determination of formaldehyde by the 2,4-dinitrophenylhydrazine-coated silica gel cartridge method. At 120 ppb of ozone, formaldehyde at 40 ppb was under-reported by the cartridge method by 34% and at 300 ppb of ozone, formaldehyde measurements were 61% low. Greater losses were seen at higher ozone concentrations. Impinger sampling (2,4-DNPH in acetonitrile) showed no formaldehyde losses due to ozone.

Comparison of different methods for determination of sub-ppb levels of NO2 in ambient air using solid adsorbent sampling

Different methods were tested for the determination of low NO2 levels in ambient air using solid adsorbent sampling. The most promising technique was found to be adsorption on a diphenylamine(DPA)-coated surface. The formed reaction products were quantified by high-performance liquid chromatography. Compared with classical wet-chemical techniques considerably lower detection limits and blank values were obtained (typically <0.05 Μg NO2/m3 at a sample volume of ≥1 m3 and a sample flow rate of 1–2 l/min). At levels larger than 1–2 Μg NO2/m3 the results from ambient air measurements were in good agreement with a modified Griess-Saltzmann procedure using impinger sampling. A detailed description of the sampling conditions, working procedure and recovery rates are given. Other solid adsorbent sampling techniques based on triethanolamine-coated solids were also tested but in general the collection efficiency was unsatisfactory. The described DPA method is well-suited for remote area sampling of concentrations well below 1 Μg NO2/m3.

A Laboratory Evaluation of Two Methods for Measuring Low Levels of Formaldehyde in Indoor Air

Two methods for measuring formaldehyde at ppb levels–the modified pararosaniline (PRA) and the modified chromotropic acid (CTA)–were evaluated in a laboratory study. A dynamic double dilution system was used to generate controlled test atmospheres of formaldehyde by the catalytic depolymerization of trioxane. Impinger samples were collected from the sampling manifold and analyzed accordingly. Both methods demonstrated good precision (3.5% for the PRA and 3.4% for the CTA) but differed in accuracy and collection efficiency. Accuracy was 87.7±7.5% for the PRA and 92.5±4.2% for the CTA, while collection efficiency was 91.9±6.9% and 98.7±4.7% respectively. These differences were mainly due to the use of 1% NaHSO3 as the absorbing solution in the CTA method. Additionally, the NaHSO3 solution has the advantage of long sample preservation, making the modified CTA the method of choice in most non-industrial indoor air sampling situations.

Determination of occupational exposure to toluene diisocyanate by biological monitoring

Exposure of workers to toluene diisocyanate monomer in a factory producing flexible polyurethane was measured using impinger and reagent-impregnated filter sampling. These techniques yielded highly concordant results so that the facile filter techniques can be recommended. The personal exposures were compared with the individual excretion of amine metabolites from the parent toluene diisocyanates. The excretion was linearly related to the product of sampling time and concentration. The biological half-lives of the amines proved to be short so that urine should be sampled 2 h after the exposure. The percutaneous absorption of the monomers could also be controlled.

Comparison of Fourier transform infrared spectrometry and 2,4-dinitrophenylhydrazine-impinger techniques for the measurement of formaldehyde in vehicle exhaust

Experiments were conducted to validate a Fourier transform infrared (FT-IR) sampling and analysis system for measurement of trace gases in vehicle exhaust utilizing gasoline-, gasohol-, diesel-, and methanol-fueled vehicles as the emission source and formaldehyde (HCHO) as the test molecule. The 2,4-dinitrophenylhydrazine impinger method was chosen as the reference method. Diluted exhaust was drawn continuously though the FT-IR cell and measured every 3 s. The FT-IR signals were averaged over a complete driving-test cycle and compared to the concentration determined from concurrent impinger sampling. By impinger measurements it was shown that HCHO losses between the tailpipe and the FT-IR cell were on the order of only 5%, independent of vehicle type or HCHO concentration (0.02-8.5 ppm). Comparisons between FT-IR and impinger measurements on 43 tests of methanol-fueled vehicles under transient conditions (diluted-exhaust HCHO 0.28-8.5 ppm) showed FT-IR/impinger = 1.055 +/- 0.095. 19 references, 5 figures, 5 tables.

Seasonal formaldehyde concentrations in an office building.

The objective of this investigation was to determine if there was a seasonal effect on formaldehyde emissions from paneling and shelving in a one story office building. Measurement of formaldehyde was done by standard impinger sampling techniques using 1% bisulfate absorbing solution and by using a dry diffusional formaldehyde monitor. Results show a definite seasonal trend for formaldehyde concentrations by either monitoring method. The formaldehyde concentrations for warm weather are about twice as great as those in cold weather. In addition the dry diffusional monitor concentrations determined were consistently low compared to impinger sampling.

Molybdenum-Blue Spectrophotometric Method for Determination of Lewisite Vapor in Air

Abstract A method was developed for determining lewisite vapor in air. The method entails the collection of lewisite in an impinger or solid-sorbent sampler, conversion of the trapped lewisite to arsenite ion, oxidation of arsenite to arsenate, and determination of the arsenate ion by molybdenum-blue spectrophotometry. Relative to other available techniques, the one described here requires a minimum of instrumentation and can be executed without the use of highly toxic lewisite solutions for instrument calibration.

Personal air samplers for measuring occupational exposures to biological hazards.

Microbiological air samplers, designed to be worn as personal samplers, were evaluated for studying occupational exposures to aerosols of infectious and allergenic materials. Gelatin filter media, an impinger sampler, and spiral and cascade impactors were tested for collection efficiency for small (less than or equal to 2 microns) latex spheres and for recovery of bacterial aerosols. Only 20% of an aerosol of 0.8 micron latex particles passed through the impinger uncollected, while recovery of bacteria equalled or exceeded collection in an all-glass impinger. Gelatin filters matched the collection efficiency of membrane filters, but were unsatisfactory for the isolation of bacteria sensitive to dehydration. The spiral sampler and the cascade impactor provide information on the size distribution of collected particles, although, at present, collection efficiencies for very small particles are too low for rigorously quantitative studies. Methods of collection, and sampling strategies for biological aerosols are similar to those used for measuring exposures of workers to chemical and mineral aerosols; however, preparation of samples and identification of isolates may have to be referred to experts in the fields of bacteriology, virology, and mycology.

A Comparison of Two Ozone Sampling Methods

A study was conducted to compare the alkaline potassium iodide (AKI) impinger method versus a direct-reading chemiluminescent monitor for determining ozone concentrations. Comparisons were made in both a controlled laboratory situation and in the field during MIG welding. Laboratory results indicated that the accuracy of the AKI procedure is affected by sample size. In the field, AKI impinger samples seemed to give very low estimations of the true ozone concentration. The direct-reading chemiluminescent monitor performed excellently in both the laboratory and field, and exhibited its merit as an industrial hygiene field instrument.

A Comparison of Two Ozone Sampling Methods

A study was conducted to compare the alkaline potassium iodide (AKI) impinger method versus a direct-reading chemiluminescent monitor for determining ozone concentrations. Comparisons were made in both a controlled laboratory situation and in the field during MIG welding. Laboratory results indicated that the accuracy of the AKI procedure is affected by sample size. In the field, AKI impinger samples seemed to give very low estimations of the true ozone concentration. The direct-reading chemiluminescent monitor performed excellently in both the laboratory and field, and exhibited its merit as an industrial hygiene field instrument.

Occurrence of the Blue Crab Callinectes Sapidus in the Tidal Freshwater Reaches of the Delaware and Schuylkill Rivers in 1976

Impingement samples collected at four electric generating stations in Philadelphia in 1976 contained blue crabs, Callinectes sapidus, previously unreported from the tidal freshwater Delaware and Schuylkill rivers. Specimens were collected in the spring and fall in the Delaware River, but were absent during July, August, and most of September when dissolved oxygen (DO) was lowest. Low DO may have excluded crabs from the Delaware River during the summer; specimens were collected throughout the summer in the Schuylkill River where minimum observed DO was higher than in the Delaware.

Determination of Carbonyl Compounds in Automobile Exhausts and Atmospheric Samples

Abstract Two new methods were developed to determine carbonyl compounds in auto exhaust and atmospheric samples. A gas Chromatographic system using a quartz glass capillary column combined with selective and sensitive electron capture detection was used. 2,4-Dinitrophenylhydrazone derivatives of the carbonyl compounds are electron capture sensitive. The aldehydes and ketones were trapped in impinger sampling flasks containing the reagent solution. The excess of reagent was removed before injection onto the glass capillary column. A reversed phase high performance liquid chromatographic system for separation of fluorigenic dansylhydrazones is presented. With this system a complete separation of 17 carbonyl compounds was achieved. The reaction conditions for the dansylhydrazine reagent was studied and compared to the 2,4-dinitrophenylhydrazine reagent. The gas chromatographic method was also compared to the different liquid chromatographic methods applied on some atmospheric and auto exhaust samples. The me...

Evaluation of dust exposure in asbestos cement manufacturing operations.

Previous investigations of the health of workers of the asbestos cement industry have demonstrated dose-response relationships for the diffuse radiographic changes of asbestosis and pulmonary function impairment. Studies of the mortality experience of past employees have also identified levels of cumulative exposure above which an excess of respiratory cancer could be detected. These epidemiologic studies were based on particulate concentrations determined by the midget impinger. We attempted to develop information that might lead to conversion of particulate to fiber concentrations in the industry in order that the risk assessment could be related to the current membrane filter methods. Pairs of impinger and membrane filter samples were taken in the various areas of the plant. Personal samples were also taken to determine the current exposure of workers. The ratio of fiber concentration to particle count varied from 0.63 to 2.5. Por correlation (0.18) was obtained at low fiber and particle counts and good correlation (0.91) was demonstrated in dustry areas where asbestos and silica were handled in a dry form. The concentration of fibers in 80% of the personal samples was less than 2 fibers/cc, and 60% were less than 0.5 fibers/cc. The results also show that no one conversion factor can be used for all areas of this type of operation.