Showing papers on "Particulates published in 1979"

Concentration and size distribution of particulate trace elements in the south polar atmosphere

Abstract: Samples of atmospheric particulate material were collected at the South Pole between December 1974 and February 1975. The filter samples were analyzed by neutron activation analysis and atomic absorption. The concentrations of 36 trace elements were determined and compared to previous results of antarctic research. The source of many of the elements can be identified as either the weathering of crustal material or oceanic sea salt. These sources account for approximately 10% of the particulate mass measured. Volatile elements not strongly associated with either of these two sources are Zn, Cu, In, W, Sb, Pb, Au, As, Ag, Cd, Se, Br, and I, which account for up to 3% of the particulate mass measured. The mass of the antarctic aerosol is dominated (∼80–90%) by sulfate, which is believed to be transported to the interior of the continent through the upper troposphere or through the lower stratosphere. Although the sources of the volatile elements are unknown, they are more closely correlated with the sulfate aerosols than with either a crustal or oceanic source.

Size Considerations for Establishing a Standard for Inhalable Particles

Abstract: The U. S. Environmental Protection Agency (EPA) is required, under the amended Clean Air Act of 1977, to review the scientific basis for the total suspended par-ticulate (TSP) ambient air quality standard and determine whether a revised particulate standard can be promulgated by December, 1980. It is recommended that research to develop information for a size-specific standard should focus on inhalable particulate (IP) matter defined as airborne particles ≤15 jum aerodynamic equivalent diameter. This particle size range relates to that fraction of particulate matter which can primarily deposit in the conducting airways and the gas-exchange areas of the human respiratory system during mouth breathing. It is also recommended that a second particle size cut-point of ≤2.5 yum diameter be incorporated in the air sampling devices, based upon considerations of the chemical composition and the size distribution of airborne particles, and on the predominant penetration of particles ≤2.5 /im diameter into the gas-e...

Global trace metal cycles and predictions

Abstract: A methodology and mathematical formulation are presented for development of the global geochemical cycles of trace metals. Global cycling models of As, Se, and Hg are discussed in detail and used to assess the impact of the activities of society on these element cycles. These models show that anthropogenic activities may have increased the global concentrations of these elements in rain, seawater, and perhaps in river water. Model calculations suggest that increased concentrations of these elements in the world's surface ocean by the year 2000 will be small. A two-reservoir, cycling model of trace metals in atmospheric particulates is developed and used to assess the sources of element enrichments in these particulates. The model enables prediction of trace metal enrichment factors in atmospheric particulates, where enrichment factor is defined as the metal/Al ratio in atmospheric particulates divided by the metal/Al ratio in soils. Correspondence between predicted and observed enrichment factors suggests that for some trace metals, their enrichments in atmospheric particulates are caused, at least in part, by the industrial and fossil fuel burning activities of society. Model calculations further show that cessation of these activities would result in a return of present-day or future enrichment factors to preindustrial values in less than one year.

Chemical element balance receptor model methodology for assessing the sources of fine and total suspended particulate matter in Portland, Oregon

Abstract: The chemical element balance receptor model i s explored a s a method of determining the major contributors t o t he f i n e and t o t a l suspended par t icu la te i n Portland, Oregon. Its major weaknesses i n previous applications a re evaluated and an attempt is made t o r e c t i f y them. Aerosol source chemical composi t ions from or ig ina l source t e s t s a r e reported, evaluated and compared with r e s u l t s from other source t e s t s . A new l e a s t squares f i t t i n g procedure which incorporates e r r o r s i n the source compositions as well a s the e r ro r s i n the ambient chemical concentrations is derived. The va l id i ty of t h i s "effect ive variancet' l e a s t squares calculat ion method is ver i f ied i n a s e r i e s of simulation s tud ies comparing it t o t he ordinary weighted l e a s t squares calculat ions used i n previous element balance studies. These simulations show t h a t the e f fec t ive variance l e a s t squares f i t is superior i n a l l respects. A method f o r identifying spec i f ic sources within a source type grouping by averaging source contributions within d i s t i n c t surface windflow pat terns is proposed. To t e s t these refinements i n the chemical element balance, f i l t e r samples of Portland's f i n e (<2 vm) and t o t a l suspended par t icu la te were taken a t s i x locations, two background, one indus t r i a l , one urban, one urban/industrial and one res ident ia l . Ninety-four days were sampled between July, 1977 and April , 1978. Three o r six sequent ia l lo-vol f i l t e r samples and one hi-vol sample of f i n e and t o t a l suspended part i c u l a t e were taken a t each s i t e . Each day sampled was c l a s s i f i ed i n t o

Bacterial activity related to sedimenting particulate matter

Abstract: The rates of sedimentation of particulate matter were measured at a station in the Eckernforde Bight, Baltic Sea, using sediment traps. Different parameters (C, N, chlorophyll a, phaeopigments, adenosine triphosphate (ATP), heterotrophic activity (glucose maximum uptake velocity, vmax), biological oxygen demand (BOD), and electron-transport-system (ETS) activity) were measured during a 1-year period to evalnate the composition, vertical distribution, and activity of microorganisms associated with sedimenting particulate matter. Measurements indicated that the organic fractions of particulate sedimenting matter were transformed considerably during sedimentation. The seasonal fluctuations showed higher heterotrophic activity durang summer and lower activity during winter. Laboratory experiments also indicated that an important part of planktonic particulate material was susceptible to mineralization within a short period of time: phytoplankton was mineralized by about 35% and “zooplankton” by about 18% per day, at 20°C; at 5°C mineralization was considerably lower (about 3 and 8%, respectively).

Simultaneous concentrations of ammonia and nitric acid in a polluted atmosphere and their equilibrium relationship to particulate ammonium nitrate

Abstract: Simultaneous absolute concentrations of ammonia and nitric acid in ambient air were measured with short integration times in Riverside, Calif. A kilometer path-length Fourier transform infrared spectrometer was utilized. During selected episodes, 24 hr high volume particulate samples were also collected and analyzed for ammonium and nitrate ions. Analysis supports the hypothesis that particulate ammonium nitrate is in equilibrium with its precursors, ammonia and HNO/sub 3/. 20 references, 3 tables.

Dynamics and distribution of suspended particulate matter in the St. Lawrence estuary

Abstract: Spot samples and tidal cycle anchor stations from Pointe des Monts to Lake St. Pierre are used to map concentrations, grain size and weight/volume ratios of suspended particulate matter. Their distributions are related to salinity, current depths and to bottom samples. A turbidity maximum maintained by tidal current

Condensation cleaning of particulate laden gases

Abstract: Particulate laden gas, especially those gases carrying particulates having a size in the micron or submicron range, are removed by humidifying the gas with water and thereafter subjecting the gas to indirect contact heat exchange sufficient to provide an energy transfer for water vapor condensation of at least 5 horsepower per 1000 cfm. Heat exchange is accomlished by passing the gas downwardly through an exchange element having smooth and vertical gas passages of a relatively large dimension.

Sources and fates of aromatic compounds in urban stormwater runoff

Abstract: Petroleum-derived aromatic hydrocarbons and associated sulfur compounds in urban storm-water runoff and Delaware River sediment samples were characterized with a gas chromatograph equipped with a flame ionization/sulfur specific flame photometric detection system. Total petroleum hydrocarbon concentrations were determined gravimetrically in storm water emanating from a northern Philadelphian storm sewer. Comparison of hydrocarbon and sulfur fingerprints of the aromatic fractions of environmental samples with reference oils indicated that crankcase oil was the most likely source of aromatics in storm-water runoff. A weathering study on used crankcase oils showed a loss of diaromatics which accounted for their absence in the environmental samples. Since aromatic sulfur compounds were preferentially associated with particulate matter in urban runoff, a mechanism was proposed in which fuel oils and lubricating oils released to the environment are adsorbed onto particulate matter. The lower boiling diaromatics are lost through natural weathering, and during a storm, the particulates are washed into sewers and then into receiving waters.

Diesel exhaust particulate traps

Abstract: Related arrangements of diesel exhaust particulate traps are disclosed wherein particulate filter elements are formed from porous ceramic monoliths made of high temperature ceramic and containing passage defining micronic pores intercepted by high temperature ceramic fibers retained in the ceramic substrate and extending into the passages to provide surfaces for separating particulates from the gases passed through the element.

A Study of Wood Stove Particulate Emissions

Abstract: Particulate emission factors for two wood stove models have been determined for two types of fuel and a range of operating conditions. The emission factors range from 1 g/kg (fuel) to 24 g/kg. A model is presented which represents the emission factor as a simple function of the ratio of fuel load to combustion rate, or the length of time between refueling. This model is felt to be appropriate for evaluating the impact of wood-based residential space heating on ambient air concentrations of particulate matter If certain assumptions can be made about stove operating conditions. An application of the emission factor model to a typical community suggests that the contribution of wood stoves to ambient particulate levels might reach 100 μg/m3 if the entire heating load were carried by wood. Preliminary analyses of the particulate matter Indicate that benzene extractables range from 42% of the total particulate mass at short refuel times to 67% at longer refuel times. About 45% of the mass of benzene extractabl...

On the formation of bubbles in gas-particulate fluidized beds

Abstract: The method of characteristics is applied to the nonlinear equations describing two-phase flow in a fluidized bed. The method shows how a small disturbance changes with time and distance and can, eventually, produce a flow discontinuity similar to a shock wave in gases. The parameters entering the analysis are the amplitude of the initial disturbance, the wavelength of the original disturbance, the particulate pressure function, the particulate size, the uniform fluidization voidage, the uniform fluidization velocity, the fluid viscosity, the particulate density, and the fluid density. A parametric study shows that the following factors delay shock formation: a decrease in particulate size, an increase in bed density, an increase in fluid viscosity, and a decrease in particulate density. Experimental data on bubble formation in gas-particulate fluidized beds show that these same factors delay bubble formation. It is concluded, therefore, that the shock front and the bubble front are one and the same thing.

Methodology for Determining Particulate and Gaseous Diesel Hydrocarbon Emissions

Abstract: The 1977 Clean Air Act Amendments, which call for broad study of motor vehicle particulate emissions, coupled with requirements for improved fuel economy, have greatly increased the interest and study of diesel powered motor vehicles. Analytical procedures are described which permit measurement of diesel organic emissions, including the particulate and gas phases, from carbon number 1 to carbon number 40. The partitioning of the emitted organics between the gas and particulate phases is examined with a variety of controllable sampling parameters. These parameters include variations in particulate sampling probe configurations and sampling rates, variable dilution ration and corresponding temperatures, and filter media.

Gas and Particle Emissions from Automobile Tires in Laboratory and Field Studies

Abstract: This paper is directed to air pollution scientists interested in special mobile emission sources. The purpose was to determine the contribution which automobile tires make to air pollution. The gaseous hydrocarbon and sulfur compounds emitted in laboratory tests were identified. Although these hydrocarbons can participate in smog reactions, their mass emission rate is less than 0.1 % of the current exhaust hydrocarbon emission rate. Hydrocarbons from tires are not measurable near a freeway. The particulate emitted from tires ranges in size from 0.01 μm to more than 30 μm, with the larger particles dominating the total mass. Measurements along a California freeway showed that most of the tire debris had settled within 5 m of the pavement edge. Airborne rubber concentrations were less than 0.5 μg/m3, or less than 5% of the total tire wear. These field measurements confirm the indoor emission pattern and verify that tire wear products are not a significant air pollution problem.

Automotive diesel engines--fuel composition vs particulates

Abstract: Forty-six experimental diesel fuels have been tested in a modern automotive diesel engine, and the effect of fuel characteristics on particulate emissions, gaseous emissions, and fuel economy has been studied. Regression analysis of results established a relationship between particulate emissions and two fuel characteristics: (1) aromatic content and (2) volatility, especially as described by the 90% boiling point. Particulates could be reduced by lowering either aromatic content or 90% boiling point.

Removal of particulates from pyrolytic oil

Abstract: A process for producing organic liquid product from solid organic waste. The process comprises pyrolyzing the solid organic waste to produce pyrolysis vapors and solid pyrolysis residue. The solid residue is separated from the pyrolysis vapors leaving entrained particulate matter in the vapor. At least a portion of the pyrolysis vapor is condensed for producing pyrolysis liquid containing entrained particulate matter. The pyrolysis liquid is centrifuged producing a light fraction containing entrained particulate matter, a middle fraction substantially free of particulate matter and a heavy fraction containing entrained particulate matter. The middle fraction is recovered as organic liquid product substantially free of entrained particulate matter. The light fraction and heavy fraction are mixed and filtered. The liquid filtrate produced is distilled for producing additional organic liquid product.

Particulate matter: its association with microorganisms and trace metals in an estuarine salt marsh microlayer

Abstract: Concentrations of bacteria, cadmium, and lead found in particulates taken from a San Francisco Bay salt marsh were determined. Data indicate that the salt marsh microlayer contains high concentrations of particulates, microorganisms, and lead; the presence of lead and bacteria on particulate surfaces indicates that microlayer particulate surfaces may be a major source of lead uptake in estuarine ecosystems. (3 graphs, 3 photos, 23 references, 2 tables)

The Characterization of the Soluble Organic Fraction of Diesel Particulate Matter

Abstract: This paper is concerned with the demonstration of a methodology for chemically characterizing diesel particulate organic matter (POM) emissions. The procedure begins with a Soxhlet extraction of the POM with dechloromethane to obtain a soluble organic fraction (SOF). The acidic and basic portions of the SOF are isolated by liquid-liquid extraction techniques with aqueous base and aqueous acid, respectively. The neutral portion of the extract is separated into paraffin, aromatic, transitional, and oxygenated fractions by column chromatography on silica gel. Two additional fractions, the ether insoluble and hexane insoluble fractions, are also separated. Quantitative mass data are presented on the extraction and fractionation of twelve particulate samples from the exhaust of a medium-duty diesel engine collected in a dilution tunnel at a volume dilution ration of 8 to 1. Three fuels with a range of properties and two steady-state engine conditions from the EPA 13 Mode Cycle were used as experimental variables.

Characterization of Particulate and Gaseous Emissions from Two Diesel Automobiles as Functions of Fuel and Driving Cycle

Abstract: Particulate and gaseous emissions from two-light-duty diesel vehicles were measured over eight operating schedules, using five different fuels. Characterization included regulated exhaust emissions and a number of unregulated constituents. Non-routine gas measurements included phenols, hydrocarbon boiling range, and aldehydes. Particulate characterization included mass rates and concentrations, visible smoke, aerodynamic sizing, total organics, sulfate, phenols, trace elements, and major elements. Statistical analysis of emissions data was undertaken using fuel properties and operating schedule statistics as independent variables. Regressions were computed for a few variables, and analysis of variance and multiple comparisons were used where the data were not suitable for regression analysis.

Distribution of particulate organic carbon and nitrogen in the Bering Sea and northern North Pacific Ocean

Abstract: Particulate matter was collected in the Bering Sea and the northern North Pacific Ocean during the cruise of R. V. Hakuho-maru, Ocean Research Institute of Tokyo University in summer of 1975. The particulate matter was analyzed for organic carbon and nitrogen, chlorophylla and amino acids. The concentrations of particulate organic carbon and nitrogen were measured with the range of 16–422ΜgC l−1 and 1–85ΜgN l−1, 19–186ΜgC l−1 and 1–26ΜgN l−1, 46–1,038ΜgC l−1 and 6–79ΜgN l−1 and 19–246ΜgC l−1 and 2–25ΜgN l−1 in the Oyashio, the Deep Bering Sea, the continental shelf of Bering Sea and the northern North Pacific, respectively. Particulate organic carbon and nitrogen decreased with depth throughout the areas. The average concentrations of organic carbon and nitrogen in the entire water column tended to decrease in the following order; the continental shelf > Oyashio > northern North Pacific > Deep Bering Sea. C/N of particulate matter varied in the range of 3–15 (7 on average) in surface waters throughout the areas and these values tended to increase with depth to 5–20 (11 on average) in deep waters without significant regional variability. Linear regressions between chlorophylla and particulate organic carbon in the euphotic layers indicate that detrital organic carbon accounted for 34.2, 44.9, 49.1 and 25.2 % of particulate organic carbon in the Oyashio, the Deep Bering Sea, the continental shelf and the northern North Pacific, respectively. Particulate amino acid was determined in the range of 10.3–78.0Μg l−1, 104–156Μg l−1 and 10.4–96.4Μg l−1 in the Deep Bering Sea, the continental shelf and the northern North Pacific, respectively. Aspartic acid, glutamic acid, serine, glycine and alanine were found as dominant species of amino acid of particulate matter.