Showing papers on "Particulates published in 1973"

Chemical element balances and identification of air pollution sources.

Abstract: Air pollution sources of given types, whether natural or man-made, emit a characteristic set of chemical elements in approximately fixed proportions. If the sources in a polluted region are known, the contributions from each source can be estimated by measuring elemental concentrations at a given point and solving a set of simultaneous linear algebraic equations. The method has been applied to the particulate matter measured in the air of Pasadena over an 11-hr period and averaged over particle size. For the period in question, about 15% of the particulate matter resulted from primary natural sources and 25% from primary man-made sources. About 40% of the total results from atmospheric reactions with one quarter produced by the conversion of gas phase hydrocarbons to particulate form. The estimate for this figure is based on a carbon balance. Altogether, about 70% of the total particulate burden has been accounted for with water probably making up a significant portion of the missing 30%. Improvements and extensions of the method are discussed.

Pb in Particulates from the Lower Atmosphere of the Eastern Atlantic

Abstract: MAN-INDUCED changes affecting the trace metal composition of seawater through river runoff have their initial effects in coastal regions close to the source of pollution. It is now recognized, however1,2, that atmospheric transport can introduce pollutants directly to the open ocean. There are still few data on the trace metal compositions of atmospheric particulates from oceanic areas and those that are available3–5 are from latitudinally restricted locations. Recently, we have carried out a sampling programme6–8 in which particulates have been collected from seawater and from the lower atmosphere (∼15 m above the sea surface) over large tracts of the world ocean. The collection details have been described elsewhere6 and here we present data on the concentration of Pb in atmospheric particulates collected along the length of the Atlantic Ocean from a variety of air masses. The results are listed in Table 1, and the ship's track is shown in Fig. 1.

Characterization of particulate matter in vehicle exhaust.

Abstract: The particulate matter entitted from present-day cars is a complex mixture of inorganic salts, soot and carbonaceous material. Measurement and characterization of such particles require elaborate sampling systems and sophisticated analytical techniques. This paper is a review of the major contributions in this area. A number of systems suitable for sampling and characterization of the exhaust particles are described. Also included is a wide selection of data from a number of workers that, in the author's opinion, best represent the state of the art. /Author/

Chemistry of the lower atmosphere

Abstract: The presence of particulate matter in the lower atmosphere is considered, giving attention to the sources of particles in the troposphere, the composition of particles collected from the atmosphere, aspects of particle concentrations and size distributions, mechanisms of removal, residence times, and conditions in the lower stratosphere. The role of natural and anthropogenic pollutants in cloud and precipitation formation is discussed together with removal processes of gaseous and particulate pollutants, and the global sulfur cycle. Other topics examined include the chemical basis for climatic change and the carbon dioxide cycle. Individual items are announced in this issue.

Outdoor-indoor levels of six air pollutants.

Abstract: Comparisons were made of the levels of six air pollutants—total oxidant, per-oxyacetyl nitrate (PAN), nitric oxide, nitrogen dioxide, carbon monoxide, and particulate matter—outside and inside 11 buildings in the South Coast Basin of California during summer and fall. Total oxidant levels inside depend upon how much outside air is being brought in and the residence time in the structure. With rapid intake and circulation, levels inside may be two-thirds those outside. With little intake and slow circulation, amounts inside decay to near zero. PAN is more persistent in buildings because it is more stable than ozone but also decays to low levels over an extended period. Oxides of nitrogen and CO are much more stable than oxidant or PAN and when carried into buildings remain until diluted or exhausted. Particulate matter levels indoors depend largely upon velocity of air movement. Indoor areas where foot traffic was light or which had low ventilation rates had reduced amounts of particulate. Electrostatic pr...

Particulate and gaseous halogens in the Antarctic atmosphere

Abstract: Surface level atmospheric particulate and gas samples were collected near McMurdo station (77°51′S, 166°40′E) and Amundsen-Scott station (90°S) during November and December, 1970. Particulate samples were analyzed for iodine, bromine, and chlorine and gas samples for iodine and bromine by thermal neutron activation. There was evidence of camp contamination for some of these samples at both stations. For uncontaminated samples the mean halogen concentrations were as follows: Considerations of variations in the gaseous and particulate I/Br ratios and the gaseous to particulate iodine and bromine ratios in Antarctica and Hawaii suggest that particulate bromine and gaseous bromine both have shorter residence times in the marine atmosphere than the respective iodine species and that gaseous iodine and bromine both have relatively long residence times (of the order of months) over the polar plateau.

The Determination of Lignin in Marine Sediments and Particulate Form in Seawater

Abstract: Alkaline nitrobenzene oxidation was used to produce vanillin and syringaldehyde from the lignin fraction of marine sediments and particulate matter filtered from seawater. Results indicate that this material constitutes a substantial proportion (1-14%) of the organic matter in the sediments and that a general background level (20-60 mcg/1) of material in the suspended fraction is attributable to lignin. The highest levels were found in the vicinity of forest industry plants.

Modeling of the Effects of Gaseous and Particulate Pollutants in the Urban Atmosphere. Part I: Thermal Structure

Abstract: The short-term effect of radiatively participating pollutants upon the temperature distribution in the boundary layer of the urban atmosphere is predicted. This is accomplished by constructing a mathematical model for atmospheric radiation transfer and one-dimensional mass, momentum and energy transport in the planetary boundary layer. The atmosphere, consisting of gaseous and particulate pollutants as well as natural constituents, is considered to absorb, emit and scatter anisotropically radiant energy. A series of numerical simulations of the thermal structure in the urban atmosphere is performed for summer and winter conditions, with and without an elevated inversion. The numerical simulations stowed that the aerosol pollutants reduced the solar radiant flux at the surface which in turn lowered its temperature during the day. The additional solar heating due to the pollutants caused the atmosphere to be slightly warmer at higher altitudes. The surface temperatures during the day were slightly ...

Sensing presence of fire

Abstract: Both the spectral absorption characteristic of air to test for gaseous combustion products, and the dispersion characteristics of atmosphere, to test for particulate matter, aerosols, smoke, and the like therein, are analyzed, and if there is coincidence of presence of carbon monoxide, and/or carbon dioxide, as well as dispersion of light, an alarm signal is generated. The light source is preferably a light emitting diode, such as a tri-metal laser diode so that the radiation is in the spectral region in which absorption bands of gaseous combustion products can be sensed. The same light source may be utilized to also illuminate the atmosphere to test for particulate matter.

Average Trace Element Composition of Low Level Marine Atmospheric Particulates

Abstract: GROWING concern has been expressed1,2 over the introduction of pollutant trace metals to the oceans through the atmospheric transport of particulates from the continents. Few data exist on the elemental composition of such particulates, and those available are usually from restricted regions3–5. We have carried out a sampling programme6,7 in which particulates have been collected from seawater and from the lower atmosphere (∼ 15 m above the sea surface) over large tracks of the world ocean. The collection details have been described elsewhere6 and the distribution of Pb in Atlantic particulates has been reported7. Here we present data on the average trace metal composition of aeolian particulates from the lower atmosphere of various major wind systems over the World Ocean.

Oceanic Aerosol Levels Deduced from Measurements of the Electrical Conductivity of the Atmosphere

Abstract: The electrical conductivity of the atmosphere, monitored at sites remote from sources of anthropogenic aerosols, may be used to provide an index of the level of suspended particulates for the area representative of the sampling site. Conductivity measurements taken at Mauna Loa, Hawaii, and from ocean research vessels, indicate that most of the oceanic regions of the world are maintaining a natural aerosol level unchanged by the activities of mankind. Significant exceptions are the paths of aerosol pollution extending eastward from the United States in the North Atlantic, from Japan in the North Pacific, and southward from Asia in the Northern Indian Ocean. These regions are discussed with respect to the lifetime of the suspended particulates and the influence of large-scale atmospheric circulation. Anthropogenic aerosols are largely produced from the burning of fossil fuels such as coal and oil. The present trend is toward control of these particulate emissions and an inevitable switch to other ...

Relationship between Viable Bacteria and Air Pollutants in an Urban Atmosphere

Abstract: Significant correlations were found between the concentration of viable airborne bacteria and the concentration of CO (−0.61) and hydrocarbons (+0.51) in measurements made in Cincinnati during the summer of 1969. No statistically significant correlations were found between bacteria concentration and temperature, relative humidity, or the concentration of total suspended particulate matter, NO, NO2, SO2) and oxidants. Partial correlation analysis where temperature and humidity were held constant, however, revealed significant correlations between bacteria concentration and the concentrations of NO (+0.45), NO2 (+0.62), SO2 (−0.76), hydrocarbons (+0.57), and CO (−0.54). Bacterial size expressed as the mass median diameter (7.6 μm average) was significantly correlated with relative humidity (−0.71)) and CO concentration (−0.60).

Method and apparatus for measuring particulate emissions in gas flow

Abstract: A stack sampler for collecting particulate samplings in gaseous emissions includes means to match the volume rate of flow through the sampler to the flow in the stack. Filter means removably disposed in the sampler are adapted to collect particulate matter from the gaseous emission during the isokinetic flow which is obtained. The high volume capacity of the sampler permits accurate samples to be obtained during short sampling periods.

Method of preventing environmental erosion

Abstract: The surface of a mass of finely divided particulate matter, e.g. the surface of a coal pile, is treated by applying to the surface a combination of an organic polymer latex and a silicone to provide a water repellant surface.

Process for producing a sulfur free combustible gas

Abstract: A process for producing hot combustible gas free of sulfur, halogens and particulate matter. The process comprises passing oxygen, steam and/or carbon dioxide through a reaction zone containing an alkali or alkaline earth metal oxide, hydroxide, bicarbonate or carbonate and a carbonaceous fuel such as coal. The sulfur and halogen in the carbonaceous fuel are removed resulting in a combustible gas substantially free of sulfur, halogens and particulate matter.

Apparatus and method for fluidizing and handling particulates

Abstract: An improved apparatus and method for fluidizing and handling particulate material, wherein separate means are employed to change the angle of inclination of the main support for the particulate material and to fluidize the particulate material.

Relative Efficiencies of Filters and Impactors for Collecting Stratospheric Particulate Matter

Abstract: The relative efficiencies of impactors of the type used by Junge and co-workers for collecting stratosphere sulfate particles and of filters used in these laboratories have been determined by flying these collecting devices on the same aircraft in the stratosphere. The impactors have less than 20% of the efficiency of the filters for total sulfate. At most, a small percentage of the stratospheric sulfate was present as the ammonium salt. At least about half of the ammonium ion found on the impactors could have resulted from reaction of the collected samples with ammonia in tropospheric air.

Modeling of the Effects of Gaseous and Particulate Pollutants in the Urban Atmosphere. Part II: Pollutant Dispersion

Abstract: In conjunction with a companion study, this paper discusses the pollutant dispersion as predicted by solving numerically the equations of a transient, one-dimensional transport model. The results show that while the radiative properties of the aerosols have only a slight effect on the daytime pollution concentration; they do lead to decreased instability during the day. The gaseous pollutants, however, play a major role by lifting the elevated stable region thereby reducing pollution buildup. This alteration of an elevated stable region is important since air pollution episodes usually occur when such elevated inversions are present.

Suspended particulate matter in the western north pacific ocean

Abstract: Suspended particulate material sampled from depths down to 4000 m in various areas of the western North Pacific and adjacent seas were studied. Data were collected from 95 stations including 48 large·volume water sampling stations during 13 cruises of the T.S. Oshoro-Maru, Hokkaido University, and of the R.V. Hakuho-Maru, Tokyo University, in 1965-1970. An additional series of 4 surface skimming trips were made in a small coastal embayment, Oshoro Bay, Hokkaido, in May-June, 1970. Particulate matter in terms of dried weight, carbon and nitrogen showed a fairly consistent pattern in vertical distribution through the entire areas observed. Regression analyses confirmed that the average concentration in the surface layer (0-50 m) in an area was linearly correlated with the average concentrations in deeper layers of the same area.. This finding suggests that there is a marked regionality in the particle content of the entire water column, and that the regional variation is ultimately controlled by the regional variation in primary production in the surface photic zone. The surface skin samples obtained in Oshoro Bay contained particulate carbon of the orders of 367-5174 pgCJI, which were several times higher than in the bulk water. These high concentrations combined with exceedingly high carbon/chlorophyll a ratios obtained for surface bucket samples from the oceanic areas suggest that there should be occurring an intensive particle formation that is categorically different from the photosynthetic activity.