Oil Aerosol Research Articles

Source identification and apportionment for atmospheric aerosol by factor analysis

The statistical basis for factor analysis is briefly discussed. A method combining common factor analysis with orthogonal transformation has been proposed and discussed in detail. The method has been tested with a data set consisting of 16 elemental concentrations in 40 samples collected at the Beijing meteorological tower, March 1980. Seven sources—soil+coal fly ash, sulfate, cement and lime dust, oil, plant burning, motor, and marine aerosol—corresponding to the first seven factors have been identified. The source profiles and their contributions have been obtained.

PERMETHRIN AS A LONG-TERM PROTECTANT OF WOOLEN FABRIC1

An aqueous pressurized spray and an oil aerosol formulation of permethrin were used to treat square foot samples of woolen cloth to protect it against fabric pests. Initial protection and protection through 6 months of aging was obtained against feeding damage by larvae of the black carpet beetle, Attagenus unicolor (Brahm), the furniture carpet beetle, Anthrenus flavipes LeConte, and the webbing clothes moth, Tineola bisselliella (Hummel). Additional samples were stored in a dark closet in a room maintained at ca. 24°C for 78 months and the feeding tests were repeated. Both formulations continued to provide a high degree of protection against the above species of fabric insects. Currently, a label is pending at the Environmental Protection Agency with a 6-month claim for protection in storage when applied as directed. However, an extremely high degree of protection may be obtained for several years when treated woolens are stored in the dark.

A quantitative assessment of source contributions to inhalable particulate matter pollution in metropolitan Boston

In this paper, source apportionment techniques are employed to identify and quantify the major particle pollution source classes affecting a monitoring site in metropolitan Boston, MA. A Principal Component Analysis (PCA) of paniculate elemental data allows the estimation of mass contributions for five fine mass panicle source classes (soil, motor vehicle, coal related, oil and salt aerosols), and six coarse panicle source classes (soil, motor vehicle, refuse incineration, residual oil, salt and sulfate aerosols). Also derived are the elemental characteristics of those source aerosols and their contributions to the total recorded elemental concentrations (i.e. an elemental mass balance). These are estimated by applying a new approach to apportioning mass among various PCA source components: the calculation of Absolute Principal Component Scores, and the subsequent regression of daily mass and elemental concentrations on these scores. One advantage of the PCA source apportionment approach developed is that it allows the estimation of mass and source particle characteristics for an unconventional source category: transported (coal combustion related) aerosols. This particle class is estimated to represent a major portion of the aerosol mass, averaging roughly 40 per cent of the fine mass and 25 per cent of the inhalable particle mass at the Watertown, MA site. About 45 per cent of the fine particle sulfur is ascribed to this one component, with only 20 per cent assigned to pollution from local sources. The composition of the coal related aerosol at this site is found to be quite different from particles measured in the stacks of coal-fired power plants. Sulfates were estimated to comprise a much larger percentage of the ambient coal related aerosol than has been measured in stacks, while crustal element percentages were much reduced. This is thought to be due to primary panicle deposition and secondary aerosol accretion experienced during transport. Overall, the results indicate that the application of further emission controls to local point sources of particles would have less influence on fine aerosol and sulfate concentrations than would the control of more distant emissions causing aerosols transported into the Boston vicinity.

Determining the content of oil vapor in compressed gases

Compressed gas at the exit of compressors contains mineral oils in the form of vapors and extremely fine particles forming an oily spray or a finely dispersed aerosol. When working out the specifications for cleaning the compressed gas, its oil content in the form of aerosol and as vapors should be known. This paper presents a method worked out at the ''Energokhimmash'' Special Designs Bureau for determining the content of oil vapors and the concentration of oil aerosol in gases at the exit of different types of compressors.

Conditional Sampling of Turbulence Intensities and Reynolds Stress in Premixed Turbulent Flames

Abstract Abstrac–-A two-color LDA technique has been developed for conditional sampling of intensity and Reynolds stress in premixed turbulent flame. To sample conditionally in the unburned reactants, silicone oil aerosol which burned and evaporated by combustion is used to seed the flow. Conventional AI2O3 seed particles are used to sample unconditionally through the flame. A conditional analysis method is developed to deduce conditioned data in the burned products from the unconditioned data. Comparison of the conditioned and unconditioned data obtained in a lean ethylene/air v-flame shows that the so-called flame-generated turbulence and the increase in Reynolds stress within the flame brush are caused primarily by intermittent measurements in the reactants and in the products. Using an intermittency model for the flame turbulence, the contributions due to intermittency are shown to be proportional to the difference between the conditioned mean velocities. The conditioned fluctuation inten...

Effect of equilibration zones on stability, uniformity, and homogeneity profiles of vapors and aerosols in the ADG nose-only inhalation exposure system

A commercially available, inexpensive, nose-only exposure chamber was modified to include removable equilibration zones, and the effect of these zones on chamber performance was determined. Since limited performance data were available concerning this unit, a more extensive characterization was performed. EPA limit concentrations (≧ 5 mg/liter) of toluene vapor or corn oil aerosol, and relatively low concentrations of uranine aerosol (≦50 μg/liter) were produced by standard techniques. The presence or absence of equilibration zones did not affect the stability or uniformity of toluene vapor atmospheres, with the coefficient of variation (CV) not exceeding 3.33% in all experiments. In contrast, the presence of two equilibration zones was found to progressively enhance the uniformity of the inhalable test aerosols in the animal exposure zone (CV ≦ 3.16%). Matrix sampling revealed that in both uranine and corn oil experiments, the center matrix point concentration was consistently lower than samples taken in the actual animal breathing zone. Equilibration zones markedly reduced the difference between breathing zone and center point concentrations. These performance data indicated that the modified ADG nose-only exposure system performed exceptionally well with the materials that were studied. Results were comparable to those describing whole-body chamber performance. The ready availability of this inexpensive prototype lends itself to standardization of techniques between laboratories.

Inhalation chamber with size discriminator for liquid aerosols

To minimize data variation in inhalation toxicity testing and to evaluate human and animal hazards of inhaled chemicals, a practical inhalation chamber with a size discriminator for mists was developed to provide high concentration liquid aerosols of defined particle sizes. Liquid aerosols generated with an atomizer were separated by an impinging separator which was composed of aerosol jets directed upward against a flat plate. The principle of the separator eliminates particles larger than a calculated cutoff size in micrometer and submicrometer ranges by changing the orifice diameter of the jet nozzle under constant air flow. The mists thus separated are introduced into the space between two concentric cylinders just above the impaction plate. Ten rats can be positioned around the periphery of the chamber all equidistant from the impaction plate, with their snouts thrust into the inhalation space. Preliminary testing with olive oil and water aerosols using particle cutoff sizes of 1, 3, and 3.3 μm showed that the obtained separation of particles was very clear, although the cutoff point seemed to shift somewhat to smaller values than calculated; the shift was especially evident with water aerosols. The concentrations obtained were more than 1 mg/liter when the cutoff point was selected at 1 μm. The mist at the inhalation space attained a steady concentration and particle size distribution within 2 min of the onset of mist injection, remained over a 4-hr period, and was cleared within 2 min of the cessation of mist generation.

Size Distribution of Aerosols Produced by the Laskin Aerosol Generator Using Substitute Materials for DOP

Test aerosols of di(2-ethylhexyl)phthalate (DOP) produced by the Laskin nozzle aerosol generator are widely used for in-place filter testing and respirator fit testing. Concern about health effects of DOP has led to a search for substitute materials for use as a test aerosol. Aerosols were generated with a Laskin generator and diluted 4800-fold with clean air. Size distributions were measured for DOP, di(2-ethylhexyl)sebecate, polyethylene glycol, mineral oil, and corn oil aerosols with a PMS ASAS-X optical particle counter. Distributions gave count median diameters from 0.22 to 0.30 µm. Size distributions varied little with aerosol material, operating pressure, or liquid level. Mineral oil and corn oil gave the closest agreement to the DOP size distribution.

Size Distribution of Aerosols Produced by the Laskin Aerosol Generator Using Substitute Materials for DOP

Test aerosols of di(2-ethylhexyl)phthalate (DOP) produced by the Laskin nozzle aerosol generator are widely used for in-place filter testing and respirator fit testing. Concern about health effects of DOP has led to a search for substitute materials for use as a test aerosol. Aerosols were generated with a Laskin generator and diluted 4800-fold with clean air. Size distributions were measured for DOP, di(2-ethylhexyl)sebecate, polyethylene glycol, mineral oil, and corn oil aerosols with a PMS ASAS-X optical particle counter. Distributions gave count median diameters from 0.22 to 0.30 µm. Size distributions varied little with aerosol material, operating pressure, or liquid level. Mineral oil and corn oil gave the closest agreement to the DOP size distribution.

Production of pharmacologic monodisperse aerosols.

Monodisperse aerosols containing a range of chemical material, including pharmacologically active substances, were produced by using a modified Sinclair-LaMer condensation generator. Instead of the usual hot-wire technique, an ultrasonic nebulizer was used to suspend nuclei in the gas phase as an aqueous polydisperse aerosol. This technique allowed the generation of monodisperse oil (sebacate) aerosols containing nuclei of sodium chloride, histamine, methacholine, antigen, iron oxide, methylene blue, uranine, radioactive technetium pertechnetate, and technetium-labeled human serum albumin. Quantitative agonist activity was demonstrated for each active nucleus. Particle sizes ranged from 0.65 to 3 microns, with a geometric standard deviation of 1.1-1.2. This system can produce a stable, monodisperse, biologically active radiolabeled aerosol for a period of several hours.

Environmental oil aerosol

Environmental oil aerosol

Effect of oil mists on the irritancy of sulfur dioxide. I. Mineral oils and light lubricating oil

The increase in pulmonary flow resistance in unanesthetized guinea pigs was used to assess the effect of sub-micrometer oil aerosols on the response to sulfur dioxide. At a concentration of about 10 mg/m3 neither a medicinal grade mineral oil nor a light lubricating oil altered the response when given simultaneously with 1 or 10 ppm sulfur dioxide. The naphthenic medicinal oil at 100 mg/m3 failed to protect against 50 ppm sulfur dioxide when administerd simultaneously. A 30-minute pre-exposure, however, conferred complete protection. A paraffinic laboratory grade mineral oil conferred protection when given simultaneously but was less effective when the pre-exposure protocol was used.

Wind tunnel testing of flue gas dispersion

The paper describes a versatile wind tunnel technique for the combined qualitative/quantitative exploration of flue gas dispersion from chimneys and stacks. In the method, a photo-electric probe is used to measure the concentration of a highly visible oil aerosol representing the prototype effluent. Experimental facilities, including an air-speed indicator suitable for the measurement of low wind tunnel velocities are described. The accuracy of the method is estimated, and an example of a typical application is given. Based on the latter, conclusions are drawn concerning the effects of topographic features on the ground-level distribution of gaseous stack effluents.

Respiratory deposition and early distribution of inhaled vegetable oil aerosols in mice and rats

Female mice or rats were exposed to small-particle aerosols (mass median diameter 2.1 μm) of vegetable oil containing an inert radiol-labeled tracer. The level of radioactivity in the exposure chamber was monitored, and the amounts inhaled were determined from estimates of average respiratory minute volumes of the animals and the duration of exposure. By counting the radioactivity in head, lung, trachea, esophagus, stomach and duodenum, the deposition and early distribution in these organs were calculated. Of the calculated amount inhaled, the percentage found following whole-body exposure of mice was: head, 9.1%; lung, 3.8%; stomach, 59%; esophagus, 4.7%, and duodenum, 7.0%. Comparable figures for rats were: head, 3.1%; lung, 9.9%; stomach, 13%; esophagus, 0.4%, and duodenum, 1.9%. The amounts in the trachea were generally negligible in both species.

Concentration meter for wind tunnel studies of gaseous dispersion

A photo-electric technique is described for instant determination of contaminant concentration in wind tunnel studies of stack gas dispersion. In the method, a roving sensor is used to measure the light scattered by the particles of oil aerosol representing the prototype stack effluent. The miniature probe has a noise level of only 1 × 10 −5 of the full linear range of the output signal for a time constant of 5 s. However, the device is also suitable for the measurement of fluctuating flow properties, such as turbulence, where a high frequency response is required.

Removing 99.99998% of oil aerosols from compressed air and other gases

AbstractThe oil and water particulates in compressed air and other gases are present as sprays, mists, fogs, smoke, fumes and vapors. The best method found to date for removing the oil and water contaminants from compressed air is a combination of direct impaction, inertial compaction, diffusion (Brownian motion) and coalescence, the latter being the main method of removing them. Baffles, centrifugal flow and flow directional changes of the air stream are helpful in causing coalescence and impingement. Flowing the air through porous media also is effective. The best way to coalesce liquid particulates from compressed air is to control the air flow and velocity as it passes through a fibrous bed that has predetermined porosity and which has minute strands and permanent electrostatic charges. An element designed with a prefilter with tiny pores in a cloth‐like layer such as silicon‐treated borosilicate enhances coalescing of the liquids. The air passageway between the random microfibers of inert strands located in the next layer through which air travels, and at right angles to the air stream, is very small. he strands must also be very fine (0.5 μ mean diameter). Because of the smaller open area and the smaller diameter of the fibers, this material is more effective as a coalescer of liquid droplets from 5 μ in size down to 0.01 μ in size. This structure also removes small solid particulates by diffusion (Brownian motion) and direct or inertial impaction. As long as air is flowing this design results in an almost continuous film of liquid on the outer layer. Ordinarily excessive air velocities in an element of this kind will cause subdivision of coalesced droplets. An outer cover of a material like a soft plastic, porous foam traps the coalesced film of liquid something like a sponge sleeve would “soak” liquids off a wetted outer cylinder wall. By gravity the liquids migrate down within the foam cover, dropping off the bottom of it and into the sump, out of the gas system.

Profiles of the Round Turbulent Jet in A Cross Flow

The shape of a jet issuing normal to a uniform cross wind has been studied experimentally for a large range of jet-to-wind velocity ratios, R , and over a large distance downstream of the source. Photographs taken of an oil aerosol jet were used to determine the size and position of the jet, and mean velocity measurements were made close to the outlet. Dimensional analysis shows that for negligible viscous stresses the jet profile and cross-section size are functions only of R . A momentum flux equation combined with experimental observation leads to a single form for the profile, with all linear dimensions divided by R . Experimental measurements also show that the shape follows the same parameter, and indicate zones of the jet in which the translational and vortex motions dominate. Consequences of the form of the results are discussed.

Effect of Concentration of DDT in Oil Aerosols on Toxicity to Mosquito Larvae

Effect of Concentration of DDT in Oil Aerosols on Toxicity to Mosquito Larvae