Urban Pollution Sources Research Articles

Effect of ethylene and related hydrocarbons on carbon assimilation and transpiration in herbaceous and woody species

Although the hormonal effects of ethylene (C/sub 2/H/sub 4/) on plant growth and development are well documented, recent evidence suggests that carbon assimilation in some herbaceous species is highly sensitive to ethylene. Since ethylene is a common trace gas in many airsheds influenced by urban and industrial pollutant sources, elevated levels of ethylene may be affecting the productivity of some terrestrial vegetation. The objectives of this study were to investigate the responsiveness of carbon assimilation to ethylene and related low molecular weight hydrocarbons in plant species of dissimilar growth and physiological features, to address the physiological mechanism of photosynthetic inhibition, and to estimate minimum C/sub 2/H/sub 4/ concentrations causing incipient effects on carbon assimilation. Of the four hydrocarbons studied only ethylene influenced carbon assimilation in a variety of species. The level of ethylene needed to elicit a change in carbon assimilation differed markedly among species. Estimated 5-h concentrations of ethylene required to influence carbon assimilation in ethylene-sensitive species ranged from 0.60 to 19.5 ..mu..mol/m/sup 3/. The ethylene-induced inhibition of photosynthesis was correlated with a decline in stomatal conductance to H/sub 2/O vapor.

INTERACTIONS AND DISTRIBUTION OF MERCURY COMPOUNDS IN THE INTESTINE OF FISH‐IMPLICATIONS FOR AQUACULTURE

ABSTRACTAquaculture facilities are often located in the proximity of agricultural, industrial, or urban sources of pollution. Utilization of water downstream from pollution sources is a general concern to aquaculturists. Rivers and coastal waters receive heavy metals from industrial and urban wastes and effluents. In most aquatic animals, the main route of heavy metal entry is via food and drink. In addition to the accumulation of heavy metals in aquatic species, we and others have shown that HgCl2 and CH3HgCl inhibit intestinal absorption of amino acids and sugars. Here we present data to show the generality of this effect among several species. The data also show that HgCl2 is a more potent inhibitor than CH3HgCl.In order to further elucidate the mechanisms of action of mercury, we have examined the movement of 203HgCl2 and CH3203HgCl from the intestinal lumen to the blood using a free swinnning in vivo procedure in the toadfish, Opsanus tau. Intestinal tissue and luminal fluid were analyzed after each incubation period. It was observed that both compounds appear in the tissue fraction within the first hour. CH3HgCl rapidly transfers to the blood, while HgCl2 exhibits a slow but evident transfer. Much of the HgCl2 in the tissue fraction was carried back to the luminal fluid by the mucus, suggesting binding to the luminal surface with little intracellular entry. CH3HgCl mainly moved into the tissue and then the blood with little or none being returned to the luminal fluid bound to mucus. Differences in the site of action of these two compounds was suggested.

Street sweeping as a water pollution control measure: Lessons learned over the past ten years

Street surfaces are both sources of urban runoff pollutants and pathways for the transport of pollutants originating from adjacent land areas. This view has led to the suggestion that street sweeping may be a valuable best management practice (BMP) for the control of urban runoff quality. Initial investigtions beginning in the early 1970's indicated that changes in street sweeping practices could be beneficial in reducing urban runoff pollution. In response to this early research, the U.S. Environmental Protection Agency sponsored Nationwide Urban Runoff Program adopted a broad-based assessment of street sweeping as one of its central research elements. The key finding of street sweeping research to date is that as a general, broad-based water quality best management practice it does not appear to be effective in reducing end-of-pipe urban runoff pollution loads. Under favorable conditions, reduction of about 30 percent can be expected, but more typical performance is in the 10 to 30 percent range. For certain constituents such as lead, where street surfaces are the overwhelming sources, street sweeping can control well of 50 percent of the loads. There are other specific condition where street sweeping can be effective.

On the Origin of Carbonaceous Particles in American Cities: Results of Radiocarbon “Dating” and Chemical Characterization

During the past three years radiocarbon assay has emerged as a primary tool in the quantitative assignment of sources of urban and rural particulate pollution. Its use in several major field studies has come about because of its excellent (fossil/biogenic) discriminating power, because of advances in 14C measurements of small samples, and because of the increased significance of carbonaceous particles in the atmosphere. The problem is especially important in the cities, where increased concentrations of fine particles lead to pollution episodes characterized by poor visibility and changes in the radiation balance (absorption, scattering), and immediate and possibly long-term health effects. Efforts in source apportionment in such affected areas have been based on emissions inventories, dispersion modeling, and receptor modeling – ie, chemical and physical (and statistical) characterization of particles collected at designated receptor sites. It is in the last category that 14C has become quite effective in helping to resolve particle sources. Results are presented for studies carried out in Los Angeles, Denver, and Houston which incorporated 14C measurements, inorganic and organic chemical characterization, and receptor modeling. The 14C data indicated wide ranging contributions of biogenic and fossil carbon sources – eg, <10% to 60% contemporary (biogenic) in Houston – depending on meteorological, biological, and anthropological activity. The combined (chemical, isotopic, statistical) data point to sources such as vehicles, wood combustion, power plants, and vegetation.

Evaluation of a versatile gas sampling container design

A versatile gas sampling container design has been in use for several years in the Air Pollution Section at Washington State University (WSU). Both background ambient air and gases from urban, indoor, and other pollutant sources have been successfully sampled, transported, and analyzed in containers of this design.

Temporal Variations in Atmospheric Water Vapor and Aerosol Optical Depth Determined by Remote Sensing

By automatically tracking the sun, a four-channel solar radiometer was used to continuously measure optical depth and atmospheric water vapor. The design of this simple autotracking solar radiometer is presented. A technique for calculating the precipitable water from the ratio of a water band to a nearby nonabsorbing band is discussed. Studies of the temporal variability of precipitable water and atmospheric optical depth at 0.610, 0.8730 and 1.04 microns are presented. There was good correlation between the optical depth measured using the autotracker and visibility determined from National Weather Service Station data. However, much more temporal structure was evident in the autotracker data than in the visibility data. Cirrus clouds caused large changes in optical depth over short time periods. They appear to be the largest deleterious atmospheric effect over agricultural areas that are remote from urban pollution sources.

Leaf Burning as a Significant Source of Urban Air Pollution

During the autumn of 1975, the Iowa Department of Environmental Quality conducted a study to determine the impact of the open burning of leaves on local air quality in the Des Moines (Iowa) metropolitan area. The results of the study show that open burning can cause excesses of National Ambient Air Quality Standards for particulates and carbon monoxide in heavily populated residential areas.

Degree and Sources of Urban Lead Pollution

Degree and Sources of Urban Lead Pollution

The Vertical Distribution of Cloud and Aitken Nuclei Downwind of Urban Pollution Sources

Abstract Simultaneous airborne observations of Aitken and cloud nuclei upwind and downwind of Buffalo, N.Y., were made in an effort to determine the effects of air pollution on condensation nucleus concentration. The data show significant increases over background concentrations of both Aitken and cloud nuclei (at 0.3% supersaturation) immediately downwind of pollution sources, and, also, that a secondary maximum in cloud nucleus concentration usually occurs about 10–15 mi farther downwind. In spite of these large increases in the total number of nuclei downwind of an industrial-urban complex such as the Niagara Frontier, the concentration of cloud and Aitken particulates approaches upwind background levels within 20–50 mi of the sources. Attempts to define the role (if any) of air pollution in cloud microstructure were confined to a single set of airborne observations. The limited drop-size distribution and cloud nucleus data were not sufficient to justify firm conclusions, and additional measurements ar...

Automobile Emission Reduction and Environmental Protection through Use of Green Renewable Fuel

Fossil fuels are the chief contributors to urban air pollution and major source of green house gases and considered the prime cause behind the global climate change. With the increasing fuel prices, the auto industry forced to make their engines to breathe cleanly and fuel efficiently. Biodiesel is a renewable diesel fuel substitute that can be made by chemically combining any natural oil or fat with an alcohol such as methanol or ethanol. Some of the well-known liquid biofuel are ethanol for gasoline engines and biodiesel for compression ignition engines or diesel engines. Biodiesel is a renewable and environmental friendly alternative diesel fuel for diesel engine. It can be produced from food grade vegetable oils or edible oils, nonfood grade vegetable oils or inedible oil, animal fats and waste or used vegetable oils, by the transesterifcation process. Transesterifcation is a chemical reaction in which vegetable oils and animal fats are reacted with alcohol in the presence of a catalyst. The products of reaction are fatty acid alkyl ester and glycerin, and where the fatty acid alkyl ester known as biodiesel. Biodiesel is an oxygenated fuel containing 10% to 15% oxygen by weight. Using biodiesel can help to reduce the world’s dependence on fossil fuels and has significant environmental benefts. The reasons for these environmental benefits using biodiesel instead of the conventional diesel fuel reduces exhaust emissions such as the overall life circle of carbon dioxide (CO2), particulate matter (PM), carbon Monoxide (CO), sulfur oxides (SOx), volatile organic compounds (VOCs), and unburned hydrocarbons (HC) significantly. Furthermore, since biodiesel can be said a sulfur-free fuel, it has 99% less SOx emission than the diesel fuel. However, most of the biodiesel produce 10% to 15% higher oxides of nitrogen (NOx) when fueling with 100% biodie-sel for a cleaner air and cleaner environment. They are technically competitive with and offer technical advantages compared to petroleum-diesel fuel. Aside from being renewable and biodegradable, biodiesel reduces most emissions while engine performance and fuel economy are nearly the same as the conventional fuel. In this paper author have discussed various merits and de-merits of biodiesel on the environment used as C.I.Engine fuel.Key words: Biodiesel; CO2 emission; Global warming; Emission reductionDOI: 10.3126/hn.v7i0.4240Hydro Nepal Journal of Water, Energy and EnvironmentVol. 7, July, 2010Page: 65-70Uploaded date: 31 January, 2011

Rapid fluorimetric methods by instant thin-layer chromatography for the assay of phenalen-1-one and 7H-benz( de)-anthracen-7-one in polluted urban atmospheres

Through the use of the glass-fiber paper impregnated with silica gel (called instant thin-layer chromatography, or ITLC), the rapid determination of phenalen-1-one (PO) and 7H-benz( de)anthracen-7-one (BO) is facilitated. Onemethod is introduced for the specific determination of PO, and one method for the determination of both PO and BO at the same time. Both methods are superior to previous methods in terms of speed, selectivity, simplicity, and sensitivity. In addition, they give reasonable accuracy and precision. Samples from urban atmospheres and air pollution source effluents can be analyzed rapidly for PO and BO by these methods. Analysis of one sample of organic extracts would take less than 30 minutes; analysis of a dozen samples would take less than 2 h. For those laboratories without instrumentation the amount of PO and BO can be estimated by eye after separation; eight analyses for either compound can be accomplished in about 20 minutes.

Comparison of fluorimetric methods of assay for 7 H-Benz(de)anthracen-7-one in airborne particulates and air pollution source effluents

Various modifications of a thin-layer chromatography fluorimetric method for the determination of 7 H-benz(de)anthracen-7-one (BO) and phenalen-1-one (PO) in complex mixtures have been compared. The best modifications consisted of one-dimensional thin-layer chromatography followed by elution, evaporation, solution in trifluoroacetic acid, followed by either spectrophotofluorimetric or fluorimetric assay. In some cases a quenching agent was necessary to quench the fluorescence of the interferences. Urban atmospheres and air pollution source effluents can be analyzed by these micromethods. These methods with slight modification could be applied to the determination of the aza heterocyclic and the other ring-carbonyl compounds found in urban atmospheres and air pollution source effluents.

Comparison of fluorimetric methods of assay for benz( c)-acridine and benzo( h)quinoline in urban atmospheres and air pollution source effluents

Five methods for the estimation of benz( c)acridine in urban particulate samples are compared, as are three methods for benzo( h)quinoline. The methods involving thin-layer chromatography followed by some form of fluorimetry are compared with the column chromatographic absorptiometric procedure for aza compounds. Through the quick estimation of benz( c)acridine the analyst should be able to determine the presence and amount of the polynuclear aza heterocyclic compounds in urban atmospheres and other appropriate samples.

Analysis of the urban atmosphere and air pollution source effluents for phenalen-1-one and 7 H-benz (de)anthracen-7-one.

Through the use of one- and two-dimensional thin-layer chromatography and direct spectrophotofluorometric examination of thin-layer plates, two members of a new family of compounds have been found in the atmosphere. Phenalen-1-one and 7 H-benz(de)anthracen-7-one were identified and determined in particulates obtained from urban atmospheres and air pollution source effluents. Scanning techniques and other methods of analysis were also used in characterization and estimation. Two-dimensional thin-layer chromatography followed by direct spectrophotofluorometric analysis appears to be the most promising chromatographic method for the routine analysis of chemical compounds in complex mixtures. It approaches colorimetric analysis in simplicity and speed and surpasses it in sensitivity, selectivity and the amount of information that can be obtained from one analysis.

The petroleum industries' air pollution control program.

The American Petroleum Institute sponsored a research project to investigate the problem of air pollution in urban areas. This was a long-range basic study designed to find out just what chemicals go into the air and what happens to them after they become a part of the environment and how these facts relate to air pollution. The nature of chemicals identified indicated that a major source of urban air pollution might be the exhaust gases from motor vehicles. This conclusion was supported by a number of general observations, such as formation of smog clouds over main arteries of traffic in the Los Angeles basin. Industrial plants contribute to air pollution as well as the activities from human beings. It was proven that sulfur dioxide being oxidized to sulfur trioxide in the air made only an insignificant contribution to the smog phenomenon. It was also proven that the high ozone content typical of Los Angeles smog is not characteristic of other localities. The sulfur dioxide content of Los Angeles air was found to be much lower than that of the other cities studies.