Showing papers on "Particulates published in 1997"

Pb isotopic composition of airborne particulate material from France and the Southern United Kingdom : Implications for Pb pollution sources in urban areas

Abstract: PB isotopic studies of airborne particulate matter, incinerator ash, and gasoline have been carried out to determine sources of Pb pollution in urban areas from France and the southern United Kingdom. Pb 206-207 isotopes ratios in gasoline range from 1.061 to 1.094 (average values are 1.084 for France and 1.067 for the UK) while for industrially-derived Pb, Pb 206-207 isotopes ratios vary from 1.143 to 1.155. Natural Pb is more radiogenic and literature values for pre-industrial sediments give Pb 206-207 isotopes ratios of 1.19-1.20 in France and 1.17-1.19 in the UK. The measured Pb isotopic signature of airborne particulate matter reflects the relative importance of each of these sources, and samples taken from urban areas close to traffic in France and the UK show Pb 206-207 isotopes ratios that vary widely from 1.085 to 1.158. While alkyl-lead additives in gasoline are typically still the dominant source of Pb in urban particulate matter, the relative importance of gasoline-derived Pb has decreased, and as a result other sources (industrial and natural) can be identified using isotopic studies. This is a consequence of recent EU environmental legislation that significantly limits concentrations of Pb in gasoline and the increased market penetration of unleaded gasoline. In addition, at a given location, the Pb isotopic composition of particulate matter can vary considerably due to temporal variations in sources (ie variations in traffic density) and with wind direction. (A)

The role of particulate size and chemistry in the association between summertime ambient air pollution and hospitalization for cardiorespiratory diseases.

Abstract: In order to address the role that the ambient air pollution mix, comprised of gaseous pollutants and various physical and chemical measures of particulate matter, plays in exacerbating cardiorespiratory disease, daily measures of fine and coarse particulate mass, aerosol chemistry (sulfates and acidity), and gaseous pollution (ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide) were collected in Toronto, Ontario, Canada, in the summers of 1992, 1993, and 1994. These time series were then compared with concurrent data on the number of daily admissions to hospitals for either cardiac diseases (ischemic heart disease, heart failure, and dysthymias) or respiratory diseases (tracheobronchitis, chronic obstructive long disease, asthma, and pneumonia). After adjusting the admission time series for long-term temporal trends, seasonal variations, the effects of short-term epidemics, day of the week effects, and ambient temperature and dew point temperature, positive associations were observed for all ambient air pollutants for both respiratory and cardiac diseases. Ozone was least sensitive to adjustment for the gaseous and particulate pollution measures. However, the association between the health outcomes and carbon monoxide, fine and coarse mass, sulfate levels and aerosol acidity could be explained by adjustment for exposure to gaseous pollutants. Increases in ozone, nitrogen dioxide, and sulfur dioxide equivalent to their interquartile ranges corresponded to an 11% and 13% increase in daily hospitalizations for respiratory and cardiac diseases, respectively. The inclusion of any one of the particulate air pollutants in multiple regression models did not increase these percentages. Particle mass and chemistry could not be identified as an independent risk factor for the exacerbation of cardiorespiratory diseases in this study beyond that attributable to climate and gaseous air pollution. We recommend that effects of particulate matter on health be assessed in conjunction with temporally covarying gaseous air pollutants.

Chemical Coupling Between Atmospheric Ozone and Particulate Matter

Abstract: A major fraction of ambient particulate matter arises from atmospheric gas-to-particle conversion. Attempts to reduce particulate matter levels require control of the same organic and nitrogen oxide (NO x ) emissions that are precursors to urban and regional ozone formation. Modeling of the gas-aerosol chemical interactions that govern levels of particulate components showed that control of gas-phase organic and NO x precursors does not lead to proportionate reductions of the gas-phase–derived components of atmospheric particles. The chemical coupling between ozone and particulate matter has implications for strategies to achieve the new ozone and particulate matter standards proposed by the U.S. Environmental Protection Agency.

Mercury from combustion sources: A review of the chemical species emitted and their transport in the atmosphere

Abstract: Different species of mercury have different physical/chemical properties and thus behave quite differently in air pollution control equipment and in the atmosphere. In general, emissions of mercury from coal combustion sources are approximately 20–50% elemental mercury (Hg°) and 50–80% divalent mercury (Hg(II)), which may be predominantly HgCl2. Emissions of mercury from waste incinerators are approximately 10–20% Hg° and 75–85% Hg(II). The partitioning of mercury in flue gas between the elemental and divalent forms may be dependent on the concentration of particulate carbon, HCl and other pollutants in the stack emissions. The emission of mercury from combustion facilities depends on the species in the exhaust stream and the type of air pollution control equipment used at the source. Air pollution control equipment for mercury removal at combustion facilities includes activated carbon injection, sodium sulfide infection and wet lime/limestone flue gas desulfurization.

Sources of Fine Organic Aerosol. 8. Boilers Burning No. 2 Distillate Fuel Oil

Abstract: Fine organic particulate matter emitted from an industrial-scale boiler burning no. 2 distillate fuel oil has been characterized on a molecular basis using GC/MS techniques. Most of the identified compound mass consists of n-alkanoic acids (42.0−51.5%), aromatic acids (5.8−22.6%), and n-alkanes (6.7−25.0%). Polycyclic aromatic hydrocarbons (PAH) and oxygenated PAH (oxy-PAH) together comprise 3.1−8.6% of the identifiable mass and together with chlorinated compounds (5.8−16.4%) show the largest variations in emission rates between the two experiments reported here. An increase in chlorinated compound emissions between tests is accompanied by a similar increase in elemental carbon (i.e., soot) and PAH emissions, which may follow the results of laboratory experiments that suggest that the presence of chlorinated compounds can enhance both soot and PAH formation. Differences between the hopanes distribution in the boiler exhaust versus that found in both vehicle exhaust and in the southern California atmosphere suggest that the oil-fired boiler exhaust is at most a minor contributor to the atmospheric aerosol, which is consistent with inferences drawn from local emission inventories.

Elemental characterization of particulate matter emitted from biomass burning: Wind tunnel derived source profiles for herbaceous and wood fuels

Abstract: Particulate matter emitted from wind tunnel simulations of biomass burning for five herbaceous crop residues (rice, wheat and barley straws, corn stover, and sugar cane trash) and four wood fuels (walnut and almond prunings and ponderosa pine and Douglas fir slash) was collected and analyzed for major elements and water soluble species. Primary constituents of the particulate matter were C, K, Cl, and S. Carbon accounted for roughly 50% of the herbaceous fuel PM and about 70% for the wood fuels. For the herbaceous fuels, particulate matter from rice straw in the size range below 10 μm aerodynamic diameter (PM10) had the highest concentrations of both K (24%) and Cl, (17%) and barley straw PM10 contained the highest sulfur content (4%). K, Cl, and S were present in the PM of the wood fuels at reduced levels with maximum concentrations of 6.5% (almond prunings), 3% (walnut prunings), and 2% (almond prunings), respectively. Analysis of water soluble species indicated that ionic forms of K, Cl, and S made up the majority of these elements from all fuels. Element balances showed K, Cl, S, and N to have the highest recovery factors (fraction of fuel element found in the particulate matter) in the PM of the elements analyzed. In general, chlorine was the most efficiently recovered element for the herbaceous fuels (10 to 35%), whereas sulfur recovery was greatest for the wood fuels (25 to 45%). Unique potassium to elemental carbon ratios of 0.20 and 0.95 were computed for particulate matter (PM10 K/C(e)) from herbaceous and wood fuels, respectively. Similarly, in the size class below 2.5 μm, high-temperature elemental carbon to bromine (PM2.5 C(eht)/Br) ratios of ∼7.5, 43, and 150 were found for the herbaceous fuels, orchard prunings, and forest slash, respectively. The molar ratios of particulate phase bromine to gas phase CO 2 (PM10 Br/CO 2 ) are of the same order of magnitude as gas phase CH 3 Br/CO 2 reported by others.

Characterization of the Particulate Phase in the Exhaust from a Diesel Car

Abstract: Diesel vehicles are a major source of fine, atmospheric particulate matter in urban environments. The influences diesel particles exert on solar radiation, on atmospheric chemistry, and on humans depend crucially on the size and chemical character of these particles. In this work, size-resolved diesel particle chemistry has been examined by collecting particles directly from a diesel car exhaust with a low-pressure impactor. The impactor samples have been weighed and analyzed chemically to construct continuous size distributions for selected compounds present in the particulate phase. Submicron diesel-particle mass size distributions displayed three log-normal modes that were centered at 0.09, 0.2, and 0.7−1 μm of particle aerodynamic diameter (EAD) and that had average geometric standard deviations of 1.34, 1.61, and 1.34, respectively. The lowest two modes had approximately the same particulate mass, whereas over 80% of the number of particles were estimated to be found in the mode around 0.1 μm. The th...

Effects of ambient particulate matter and ozone on daily mortality in Rotterdam, The Netherlands.

Abstract: The association between daily variations in all-cause mortality from 1983–1991 in Rotterdam, the Netherlands, and ambient air pollution was investigated. Twenty-four-hour average concentrations of total suspended particulates, Black Smoke, ozone, sulfur dioxide, and carbon monoxide were available on a daily basis. Every other day, total iron content in total suspended particulates samples was available. Poisson regression analysis was used to study associations between air pollution and mortality; generalized additive models were used to adjust for confounders (e.g., seasonal trends, weather). Daily mortality was associated most consistently with previous-day concentrations of total suspended particulates (relative risk = 1.05 for a change of 91 μg/m3) and ozone (relative risk = 1.06 for a change of 67 μg/m3). Total iron was associated less consistently with mortality than total suspended particulate mass was. The associations of mortality with ozone and total suspended particulates were independ...

Particulate Emission Rates from In-Use High-Emitting Vehicles Recruited in Orange County, California

Abstract: One hundred and three in-use vehicles, identified as high hydrocarbon and/or carbon monoxide emitters by remote sensing and roadside visual, underhood checks during a 1995 South Coast Air Quality Management District program, were tested on the IM240 cycle using a transportable dynamometer. Seventy-one of these vehicles were repaired as part of the program and were retested. Seventeen vehicles in the fleet initially emitted visible smoke from the tailpipe and were classified as "smokers". The fleet ranged in age from 6 to 22 years, with a median age of 12.3 years. Exhaust HC, CO, NOx, and particulate emissions (PM-10) were measured. PM-10 mass and the elemental and carbonaceous composition of the particulate matter were determined. The average fleet PM-10 emission rate was 0.138 g/mi, while the average emission rate for smokers was 0.395 g/mi. It was concluded that the casual observation of smoking vehicles was not very successful in identifying high PM-10 emitting vehicles. The particulate matter composition was primarily carbonaceous, with a variable distribution between the elemental and organic carbon fractions, and showed no significant difference in the percent organic carbon fraction between smokers and non-smokers. The PM composition differed, on average, between pre-repair and post-repair samples. The effect of the California Smog Check repair program on PM emission rates could not be evaluated due to concerns regarding the effect of vehicle conditioning on these measurements.

Contribution of particulate sulfate and organic carbon to cloud condensation nuclei in the marine atmosphere

Abstract: To identify the source of cloud condensation nuclei(CCN) in the marine atmosphere, simultaneous measurements of aerosol chemical components and CCN concentration were made over more than a year at Hahajima, the Ogasawara Islands, located on the Northwest Pacific Ocean in the lee of Eastern Asian large pollution sources. Large loading of CCN in continental air mass and long-distance transportation to the remote ocean were confirmed. Non-seasalt sulfate and water soluble organic carbon were dominant in fine aerosols and their concentration revealed significant relationships with CCN concentration, suggesting that not only sulfate but also organic aerosols play a key role in CCN formation, especially in the background atmospheric condition.

The Health Benefits of Air Pollution Control in Delhi

Abstract: An important reason for controlling air pollutants such as particulate matter or sulfur dioxide is the damaging effects they have on human health. These effects include premature death as well as increases in the incidence of chronic heart and lung disease. Estimates of the health damages associated with air pollution are important because they can provide both an impetus for environmental controls and a means of evaluating the benefits of specific pollution control policies. To estimate the health damages associated with air pollution in developing countries, policy makers are often forced to extrapolate results from studies conducted in industrialized countries. These extrapolations, however, may be inappropriate for two reasons. First, it is not clear that the relationships found between pollution and health at the relatively low levels of pollution experienced in industrialized countries hold for the extremely high pollution levels witnessed in developing countries. Levels of particulate matter, for instance, are often three to four times higher in developing countries than in industrialized ones. Second, in developing countries, people die at younger ages and from different causes than do people in industrialized countries, implying that extrapolations of the impacts of air pollution on mortality may be especially misleading. This paper reports the results of a study relating levels of particulate matter to daily deaths in Delhi, India, between 1991 and 1994. We focus on Delhi, the capital of India, because it is one of the world's most polluted cities. Between 1991 and 1994, the average total suspended particulate (TSP) level in Delhi was 375 micrograms per cubic meter-approximately five times the annual average standard of the World Health Organization (WHO). Levels of TSP in Delhi during this time period exceeded WHO's twenty-four-hour standard on 97% of all days on which readings were taken. Although particulate matter-produced by motor vehicles, smelters, the burning of refuse, and two coal-fired power plants-is Delhi's main air pollution problem, levels of sulfur dioxide (SO2) and oxides of nitrogen (NOx) are below U.S. limits.

A thermodynamic approach using group contribution methods to model the partitioning of semivolatile organic compounds on atmospheric particulate matter

Abstract: Atmospheric particulate matter is a complex mixture consisting of organic and inorganic chemicals. Their sources include various combustion processes, aerosolized dusts and soils, and chemical reactions which produce secondary aerosols. The partitioning of semivolatile toxic organic compounds (SOCs) between particulate matter and the gas phase is strongly influenced by temperature, water concentration, chemical composition of the particulate matter, and the organic fraction of the particulate matter. Many investigations have recently suggested that a considerable portion of the gas−particle (G/P) partitioning in the ambient atmosphere takes place between the liquid phase of organic aerosols and the surrounding gas phase. It has been shown that the equilibrium G/P partitioning constant, Kp, of an SOC partitioning to a given particle's liquid medium is inversely related to both the activity coefficient iγom and its saturated subcooled liquid vapor pressure, . Hence, in principal, the Kp of any SOC can be es...

Origin and decomposition of sinking particulate organic matter in the deep water column inferred from the vertical distributions of its δ15N, δ13 and δ14

Abstract: Sinking particles were analyzed for their nitrogen isotopic ratio δ15N) of total particulate nitrogen (PN), stable carbon isotopic ratio (δ13C) and radioactive isotopic ratio (δ14C) of total particulate organic carbon (POC), at three different latitudinal (temperate, subpolar and equatorial) and geomorphological (trench, proximal abyssal plain and distal abyssal plain) sites in the western North Pacific Ocean using year-long time series sediment trap systems, to clarify the common vertical trends of the isotopic signals in deep water columns. Although the δ15N and δ13C values of sinking particulate organic matter (POM) were partly affected by the resuspension of sedimentary POM from the sea floor, especially in the trench, the changes in δ15N and δ13C values owing to the resuspension could be corrected by calculation of the isotopic mass balance from δ14C of sinking POC. After this correction, common downward decreasing trends in δ15N and δ13C values were obtained in the deep water columns, irrespective of the latitudes and depths. These coincidental isotopic signals between δ15N and δ13C values provide new constraints for the decomposition process of sinking POM, such as the preferential degradation of 15N- and 13C-rich compounds and the successive re-formation of the sinking particles by higher trophic level organisms in the deep water column.

River Discharge and Wind Influence Upon Particulate Transfer at the Land Ocean Interaction: Case Study of the Rhone River Plume

Abstract: Drifters were released at the Rhone River outlet (north-western Mediterranean sea) to follow the mixing of the river plume with the marine underlying water, and to sample suspended matter during its transfer to the open Sea. Different hydrological and meteorological situations were encountered during these trackings. During the first trajectory, salinity values and river flow measurements indicate that a flood runoff occurred as an impulse with high initial velocity. The maximum transfer was completed in a day and a progressive decrease followed. Two further trajectories characterize the spreading of the river flow under steady north–north-westerly wind conditions. During the last trajectory, the role of the Rhone River flow was secondary and the buoyant river plume reacted quasi-instantaneously to a wind shift from the north to the west. Under these different environmental conditions, great variations were observed in distribution and fate of particulate matter. The decrease in salinity induced by the spreading of fresh water into the marine environment interrupted primary production and prevented its restarting whilst the riverine influence was dominant. During the spreading of runoff, a rapid concentration decrease in total suspended matter (TSM) and particulate organic carbon (POC) occurred in the vicinity of the river mouth. This implies exportation of suspended matter down through the water column. At the peak flood, the TSM concentration was high, and as much as 60% of the initial concentration of TSM was transferred down through the water column after 1 h of drifting. At the end of runoff, the TSM concentration was lower, and about 30% was exported downward. In both cases, TSM or POC concentrations remained stable after 2 h of spreading of the plume. However, the influence of wind forcing induced redispersion in the upper part of the plume of organo-mineral aggregates temporarily accumulated at the halocline.

Aerosols and climate: Anthropogenic emissions and trends for 50 years

Abstract: A global inventory has been prepared for anthropogenic particulate emissions into the troposphere that covers the period 1990–2040. The inventory provides estimates for both primary particulate emissions and secondary contributions from atmospheric chemical reactions, particularly of SO2. Using a conventional method, total worldwide anthropogenic emissions of particles <10 μm diameter are estimated at 345 Tg/yr, excluding secondary NO3− and organics. Approximately 35% of the particles entering the troposphere is airborne sulfate from oxidation of SO2 emissions. Emissions worldwide are dominated by fossil fuel combustion, particularly coal, and biomass burning. These emissions are projected to grow by 1.5 2.1 times in 2040, largely from fossil fuel combustion. Growth is expected to be greatest in the developing countries, especially India and China. Present anthropogenic emissions appear to be a small fraction of emissions from natural sources. However, the man-derived component could become comparable to natural emissions by 2040. Increased haziness may enhance negative climate forcing both directly by increased radiative scattering and indirectly by modifying cloud albedo and cover. The forcing will be spatially non-uniform, superimposed on the forcing derived from greenhouse gases.

Particulate barium stocks and oxygen consumption in the Southern Ocean mesopelagic water column during spring and early summer: relationship with export production

Abstract: Particulate barium was analysed in the upper 600 m of the Southern Ocean water column during repeated transects along the 6°W meridian in October–November 1992. The transects extended between the northern edge of the Weddell Gyre (57°30′S) in the south to 47°S within the Polar Front Zone (PFZ) in the north. From earlier studies, it is known that the largest fraction of Ba in oceanic suspended matter occurs as barite micro-crystals. In the PFZ, an increase in the particulate Ba content in surface waters and at mesopelagic depths can be significant over the investigation period (1 month) and follows the increase of primary production during bloom development. Using an inverse one-dimensional advection-diffusion-consumption model, O2 consumption between the base of the mixed layer and 1000 m was estimated. The shapes of the vertical particulate Ba profiles are very similar to those of calculated O2 consumption rates, emphasizing the close link between organic matter oxidation and Ba-barite release at a mesopelagic depth. For the southern Antarctic Circumpolar Current (ACC), depth-integrated rates of O2 consumption correlate significantly with primary production and mesopelagic particulate Ba concentration. For the PFZ, these relationships are subject to more speculation since this is a region of intense mixing, and the appropriate value of the turbulent diffusion coefficient is uncertain. For the ACC, the observed relationship presents the possibility of defining a transfer function between export production to the mesopelagic depth zone and mesopelagic Ba accumulation. The observed regression between rate of O2 consumption and primary production in the southern ACC suggests that about 10% of the synthesized organic carbon can be oxidized in the upper 1000 m of the water column.

Seasonal Changes in Quality and Quantity of Food Available for Benthic Suspension-feeders in the Golfo Marconi (North-western Mediterranean)

Abstract: Suspended particulate matter was collected, from the water layer at 10 cm above the sediments, over a period of 13 months in the Golfo Marconi (Ligurian Sea, NW Mediterranean). Measurements of seston concentration as well as the elemental (particulate organic carbon and nitrogen; POC and PON, respectively) and biochemical composition (lipids, proteins, carbohydrates, DNA) of particulate organic matter were carried out to assess quality and quantity of food potentially available to benthic suspension-feeders. Particulate organic matter showed wide qualitative and quantitative variations during the sampling year. Seston concentrations and POC did not reflect the quantity and quality of the food available to benthic suspension-feeders. The biopolymeric fraction of particulate matter (C-BPF, i.e. the sum of lipid, protein and carbohydrate carbon) was mostly composed of phytoplankton (which accounted for about 60% of C-BPF). The ratio of C-BPF to POC was utilized as a measure of the fraction which had the potential to be more readily available to consumers. Suspended organic matter showed higher values of the C-BPF:POC ratio during spring, and lower values in summer and autumn–winter. Quantitative estimates of the energy content of the suspended particulate matter were obtained from its biochemical composition. Bacterial dynamics were significantly related to changes in phytoplankton biomass. Bacteria accounted for a significant fraction of the biopolymeric carbon pool (annual average about 15%) and of the total particulate DNA (21·5%), thus enhancing the nutritional value of the particulate organic matter. The results achieved in this study indicate that the biochemical composition of the particulate matter provides additional information on the origin, quality and characteristics of the seston more readily available to benthic suspension-feeders.

Biogeochemistry of particulate organic matter transported by the Godavari River, India

Abstract: The Godavari River, the third largest river of India,has been sampled for Particulate Inorganic and OrganicCarbon (PIC, POC), Particulate Nitrogen (PN), andParticulate Amino Acids (PAA, including 2 hexosamines(HA)). During the dry season Particulate OrganicMatter (POM) in the upper reaches is relatively freshand autochthonous, in the lower reaches it is degradedand inorganic suspended matter content is higher here.In the wet season (wet monsoon) heavy rains cause abasin-wide flushing of humus from entire catchmentarea consequently POM in the river is mainly degradedand allochthonous. Annual transport of the GodavariRiver amounts to 2.81 × 10 6 ton POC, 0.29 × 10 6ton PN and 0.10 × 10 6 tonParticulate Amino Acid Nitrogen. These amounts rank theGodavari River to one of the most important organic carbontransporting rivers in the world.

Method and apparatus for separating floating and non-floating particulate from rainwater drainage

Abstract: Drainage water having floating and non-floating particulate is collected and processed to separate out in the floating from the non-floating particulate, thereby cleaning the flow of water through the system during sudden storms or during steady rainfall conditions.

Effect of Ambient Temperature and E-10 Fuel on Primary Exhaust Particulate Matter Emissions from Light-Duty Vehicles

Abstract: During the winter of 1994-1995, the State of Alaska Department of Environmental Conservation conducted a multi-faceted program designed to evaluate the impact of switching from regular gasoline to an E-10 fuel (gasoline with 10% ethanol) in Fairbanks. As part of that program, 10 in-use vehicles were tested on a chassis dynamometer at temperatures of 20, 0, and -20 degrees F using both fuels. Three of these vehicles were retested in the EPA facilities at Research Triangle Park, North Carolina, under the same conditions. Vehicles were driven over the Urban Dynamometer Driving Schedule of the Federal Test Procedure during testing. PM-10 exhaust emission samples were collected at Fairbanks, and total particulate samples were obtained at the EPA. Results from both parts of this study indicate that particulate matter (PM) emission rates increased with decreasing temperature for both fuels. The increase occurred primarily during cold starting and is assumed to be due to enrichment. Particulate matter emission rates during operation on the E-10 fuel were lower relative to rates obtained during operation on the base gasoline. Exhaust hydrocarbon and PM emissions were well correlated, suggesting that fully phased-in Federal Tier 1 vehicle emission standards will reduce PM emissions from new vehicles and that rich-operating, high emitters can be expected to have high PM emissions. (A)