Showing papers on "Particulates published in 1990"

Mortality and air pollution in London: a time series analysis

Abstract: The relation between air pollution and mortality in London was examined for the winters of 1958-1972. The data exhibited a high degree of autocorrelation, requiring analyses using autoregressive models. There was a highly significant relation between mortality and either particulate matter or sulfur dioxide (after controlling for temperature and humidity), both overall and in each individual year. Graphic analysis revealed a nonlinear relation with no threshold, and a steeper exposure-response curve at lower air pollution levels. In models with both pollutants, particulate matter remained a significant predictor with about a 10% reduction in its estimated coefficients, while sulfur dioxide was insignificant, with a large drop in its estimated coefficient. The authors conclude that particulates are strongly associated with mortality rates in London, and the relation is likely causal.

PM-10 measurements using the tapered element oscillating microbalance

Abstract: In recent years the quality of the air we breathe has become a greater factor in important environmental issues. Both outdoor and indoor air quality are areas of interest and concern in this respect. Ambient air particulate matter in addition to gas species contribute to the assessment of air quality. In this regard, instrumentation to measure particulate concentration levels is available to quantify this parameter. Particulate concentration measurements, however, are notoriously difficult to standardise. Collection efficiency difficulties and vagaries concerning the definition of particulate matter combine to create substantial uncertainties when measurements from one method or type of instrument are compared with another.

Chemical components of lower tropospheric aerosols in the high arctic: Six years of observations

Abstract: Six years of observations (1980 to 1986) of the composition of lower tropospheric aerosols at Alert on northern Ellesmere Island in the Canadian high Arctic yield insight into the seasonal variation of Arctic air pollutants as well as of substances of natural origin. A principal component analysis of 138 observations of 21 aerosol constituents (major ions, metals, nonmetallic trace elements) for the most polluted period of December to April identified not only a soil, sea salt and anthropogenic aerosol component, but also one associated with photochemical reactions in the atmosphere that occur at polar sunrise. Depending on the source of their gaseous precursors, elements in the photochemical component can be natural or anthropogenic in origin. For instance, SO4 2-, existing mostly as H2SO4, originates probably from both anthropogenic and natural sources while Br− is likely of marine origin. In contrast, SO4 2- in the anthropogenic component has the stoichiometry of NH4HSO4. In the winter months, over 90% of Arctic SO4 2- is in the anthropogenic and photochemical components. In winter, a substantial portion (11 to 35%) of Na+ is associated with the anthropogenic aerosol component suggesting either that marine aerosols have been physically or chemically modified by interactions with air pollution or that there are anthropogenic sources of Na+. The aerosol soil component is controlled by both local and distant dust sources. During a year, it has two peaks at Alert, one in April/May coinciding with the Asian dust storm season and one in September. There is a marked difference in the seasonal variation of particulate Br− and iodine concentrations in the air. Both have a peak in April/May associated with polar sunrise and, hence, photochemical reactions in the atmosphere. However, iodine also peaks in early fall. This may be a product of biogenic iodine emissions to the atmosphere during secondary blooms in northern oceans in late summer.

Contribution of the Rhoˆne River to organic carbon inputs to the northwestern Mediterranean Sea

Abstract: Particulate and dissolved organic carbon were determined in coastal waters of the Gulf of Lions, during several cruises from 1986. The input by the Rhoˆne River and its seasonal variability are studied and new data are given concerning the contribution to the Mediterranean Sea. Fluorescence measurements show the limited influence on the open sea of surface particulate matter, but suggest a bottom transport during which diagenetic evolution can occur. The remobilization of dissolved organic matter is also stressed.

Molecular and particulate depositions for regional myocardial flows in sheep.

Abstract: The deposition of microspheres in small tissue regions is not strictly flow dependent. In comparison with the soluble flow marker 2-iododesmethylimipramine (IDMI), deposition of 16.5-microns microspheres was mildly but systematically biased into high flow regions of rabbit hearts (Bassingthwaighte JB, Malone MA, Moffett T-C, King RB, Little SE, Link JM, Krohn KA. Am J Physiol 1987;253 (Heart Circ Physiol 22):H184-H193). To examine the possibility of bias in larger hearts, a similar study was undertaken in sheep. 141Ce- and 103Ru-labeled 16.5-microns microspheres in one syringe and 125I- and 131I-DMI in another syringe were injected simultaneously into the left atrium of five open-chest sheep while obtaining reference blood samples from the femoral artery. In six other sheep, one microsphere type and one IDMI were used. Hearts were removed 1 minute after injection, cut into approximately 254 pieces averaging 217 mg, and regional deposition densities calculated for each tracer from the isotopic counts. Correlations in the five animals between the two differently labeled IDMIs and between the two microspheres were both greater than or equal to 0.98. In all 11 sheep, scatter plots of microsphere deposition densities versus IDMI densities showed that differences between microspheres and IDMI had substantially more scatter (0.84 less than r less than 0.98) but were not random. Microsphere depositions tended to be lower than IDMI depositions in low flow regions and higher in high flow regions, in accord with the expected bias that at a bifurcation a microsphere is most likely to enter the branch with higher flow. There was less bias ascribable to endomyocardial/epicardial maldistribution. Thus, while microsphere depositions appear to err systematically with respect to flow when the regions of interest are small enough that the diameters of their arterioles are only a few times those of the microspheres, microspheres are, in sheep as in rabbits, adequate for estimating regional flows.

Vertical Fine Structure of Particulate Matter and Nutrients in Sea Ice of the High Arctic

Abstract: The vertical fine structure of particulate matter and inorganic nutrients through the bottom layers of sea ice was determined at a site in the Canadian high arctic. Intense vertical gradients of ch...

Associations between morbidity and alternative measures of particulate matter.

Abstract: This paper explores the association between acute respiratory morbidity and different measures of exposure to airborne particulate matter, including sulfates, total suspended particulates, and fine and inhalable particulates. Regression analysis was used to test for the impacts of these alternative measures of particulate matter on respiratory morbidity using the 1979-1981 annual Health Interview Surveys and EPA's Inhalable Particle Monitoring Network. The general results indicate that, of the surrogate measures for particulate matter, sulfates appear to have the greatest association with morbidity. To the extent that sulfuric acid aerosols are correlated with airborne sulfates, the results suggest that respiratory impairment sufficient to lead to days of reduced activity may be related to the existence of acidity in the air. These findings are consistent with the results of ecological studies reporting an association between mortality and exposures to fine particles and sulfates.

Heterogeneous production of cloud condensation nuclei in the marine atmosphere

Abstract: Model calculations are presented which indicate that newly created particles in the marine atmosphere will commonly only be able to achieve sizes, by means of gas-phase processes, sufficient to activate in cumuliform clouds. Aqueous sulfate production in such clouds will be generally necessary to grow them large enough to activate in marine stratus clouds.

Factors Influencing the Emissions of Gases and Particulate Matter from Biomass Burning

Abstract: Forest fires, whether prescribed or wild, emit a complex mixture of particles and gases into the atmosphere. The diversity of composition of combustion products results from wide ranges in fuel types, fuel chemistry, and fire behavior for fires burning in the natural environment. This chapter discusses the state of knowledge concerning the effect of these factors on emissions of different smoke components into the atmosphere from the burning of biomass.

Flow injection inductively coupled plasma mass spectrometry for the determination of platinum in airborne particulate matter

Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) with a flow injection system has been used to determine platinum in airborne particulate matter. The flow injection system had a cation-exchange resin column on-line for trapping major matrix elements and hafnium, which caused suppression of the signal intensity of platinum and a spectral interference by hafnium oxide, respectively. As this method does not require special sample pre-treatment before injection into the ICP-MS instrument, it was considered to be a very practical method. The detection limit was about 0.1 µg l–1 of platinum in a sample solution or 0.005 µg g–1 in airborne particulate matter. The method was applied to several airborne particulate matter samples. The observed concentrations were in the range 0.014–0.184 µg g–1.

The distribution of biogenic and lithogenic silica and the composition of particulate organic matter in the Scotia sea and the Drake passage during autumn 1987

Abstract: Suspended matter was collected from surface, deep and bottom waters during the ANTIPROD 3 cruise (autumn 1987) at six stations located in the Scotia Sea and analysed for biogenic silica (BSi), lithogenic silica (LSi), particulate organic carbon (POC) and nitrogen (PON). The composition of suspended particulate matter also was determined in the photic layer at 10 stations situated in the Scotia Sea, the Drake Passage, the Bransfield Strait and near the ice edge. While nutrient levelsin surface waters were always high, phytoplankton biomass was typically quite low during this season, as demonstrated by the low concentrations of chlorophyll a ( −3 ), BSi ( −1 ), POC ( −1 ). Nevertheless enhanced concentrations were measured in the vicinity of the Polar Front in the Scotia Sea (Chl a = 1.06 mg m −3 , BSi = 2.32 μ mol l −1 ) and within a diatom-dominated phytoplankton patch (Chl a = 0.48 mg m − , BSi = 4.24 μ mol l −1 ) in the Drake Passage, within the area influenced by the Antarctic Divergence. In surface waters the contribution of lithogenic to total particulate silica was generally lower than 20%. However in the vicinity of icebergs, the Antarctica coast, as well as in areas receiving eolian inputs in the northern part of the study area, the proportion of LSi was much higher (rising to 89%). Concentrations of both biogenic and lithogenic silica were uniformly low in Warm Deep Water ( −1 ). The dramatic enhancement of their concentrations in bottom waters (where BSi reached levels as high as 2.6 μmol l −1 ) is interpreted as resulting mainly from local resuspension due to bottom currents. The mean POC/PON mole ratio in the surface layer was 6.4±0.3, but increased to 10.1±0.6 in the deep and bottom water, which suggests that the nitrogen recycling is more rapid than that of carbon in Antarctic deep waters. BSi/POC mole ratios in surface waters exhibited values two to three times higher than typically found in pure diatom cultures. These results are consistent with previous observations in other sectors of the Southern Ocean showing that the biogenic particulate material is unusually rich in silica.

Decontamination of hydrocarbon contaminated soil

Abstract: The method of treating hydrocarbon contaminated soil that includes forming the soil into a flowing particulate stream; forming an aqueous liquid mixture of water and treating substance that reacts with hydrocarbon to form CO 2 and water; dispersing the liquid mixture into the particulate soil stream to wet the particulate; allowing the substance to react with the wetted soil particulate to thereby form CO 2 and water, whereby the resultant soil is beneficially treated.

Rapid Loss of Particulate Nitrate, Chloride and Ammonium on Quartz Fiber Filters During Storage

Abstract: The loss of particulate ammonium, nitrate, and chloride during storage of samples collected using PM-10 and standard high volume samplers in the Los Angeles Basin on filters of varying alkalinity, was investigated. For PM-10 samples collected on Whatman QM-A quartz fiber filters (av. filter pH = 8.6), losses of ammonium averaging 51 percent were observed after one week of storage in unsealed envelopes at room temperatures in laboratory air. The corresponding losses for nitrate and chloride were 19 percent and 65 percent, respectively. Volatilization of either NH4NO3 or NH4CI could not account for the observed losses; alternate mechanisms are discussed. Whereas the rate of ammonium ioss increased with increasing filter alkalinity, the reverse was found to be true for NO3 − and Cl−. In the PM-10 study involving three stations, the loss rate for nitrate exhibited a site dependency with a decrease being observed on moving from a coastal (Long Beach) to an inland site (Riverside). The rate of nitrate decay, pa...

Particulate materials, their production and use

Abstract: Agrochemical and other particulate compositions are formed by coacervation. The coacervate is preferably formed from two water soluble coacervating polymers and stabilizes the particles against agglomeration. The coacervate is preferably formed from a relatively low molecular weight cationic polymer and a relatively high molecular weight anionic polymer.