Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Light Pollution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources
PubMed2004

Use of the light absorption coefficient to monitor elemental carbon and PM2.5--example of Santiago de Chile.

The optical absorption coefficient, particulate matter with an aerodynamic diameter <2.5 microm, and elemental carbon (EC) have been measured simultaneously during winter and spring of 2000 in the western part of Santiago, Chile (Pudahuel district). The optical measurements were carried out with a low-cost instrument recently developed at the University of Santiago. From the data, a site-specific mass absorption coefficient of 4.45+/-0.01 m2/g has been found for EC. In addition, a mass absorption coefficient of 1.02+/-0.03 m2/g has been obtained for PM2.5. These coefficients can be used during the colder months (May-August) to obtain EC concentration or PM2.5 from a measurement of the light absorption coefficient (sigmaa). The high correlation that has been found between these variables indicates that sigmaa is a good indicator of the degree of contamination of urbanized areas. The data also show an increase in PM2.5 and EC concentration during winter and an increase in the ratio of EC to PM2.5. When the EC/PM2.5 ratio is calculated during rush hour (7:00 a.m.-11:00 a.m.) and during part of the night (9:00 p.m.-2:00 a.m.), it is found that the increase is caused by higher concentration levels of EC at night. These results suggest that the rise in the EC concentration is caused by emissions from heating and air mass transport of pollution from other parts of the city, while traffic contribution remains approximately constant.

Air Pollutants↗
PubMed2006

Temperature-dependent stress response in oysters, Crassostrea virginica: pollution reduces temperature tolerance in oysters.

Combined effects of temperature and a toxic metal, cadmium (Cd), on energy metabolism were studied in a model marine bivalve, the eastern oyster Crassostrea virginica, acclimated at 20, 24 and 28 degrees C and exposed to 50microgl(-1) of Cd. Both increasing temperature and Cd exposure led to a rise in standard metabolic rates, and combined stressors appeared to override the capability for aerobic energy production resulting in impaired stress tolerance. Oysters exposed to elevated temperature but not Cd showed no significant change in condition, survival rate and lipid peroxidation, whereas those exposed to both Cd and temperature stress suffered high mortality accompanied by low condition index and elevated lipid peroxidation. Furthermore, RNA/DNA ratios indicative of protein synthesis rate, and levels of glutathione, which is involved in metal detoxification, increased in Cd-exposed oysters at 20 degrees C but not at 28 degrees C. Implications of the synergism between elevated temperatures and cadmium stress on energy metabolism of oysters are discussed in the light of the potential effects of climate change on oyster populations in polluted areas.

Animals↗
PubMed2002

Understanding household demand for indoor air pollution control in developing countries.

More than 2 billion people rely on solid fuels and traditional stoves or open fires for cooking, lighting, and/or heating. Exposure to emissions caused by burning these fuels is believed to be responsible for a significant share of the global burden of disease. To achieve widespread health improvements, interventions that reduce exposures to indoor air pollution will need to be adopted and consistently used by large numbers of households in the developing world. Given that such interventions remain to be adopted by large numbers of these households, much remains to be learned about household demand for interventions designed (in part at least) to reduce indoor air pollution. A general household framework is developed that identifies in detail the determinants of household demand for indoor air pollution interventions, where demand for an intervention is expressed in terms of willingness to pay. Household demand is shown to be a combination of three terms: (1) the direct consumption effect; (2) the child health effect; and (3) the adult health effect. While micro-level data are not available to estimate directly this model, existing data and information are used to estimate just the health effects component of household demand. Based on such existing information, it might be concluded that household demand should seemingly be strong given that willingness to pay, based on existing information, is seemingly large compared to costs for common interventions like improved stoves. Given that household demand is not strong for existing interventions, this analysis shows that more clearly focused research on household demand for interventions is needed if such interventions are going to be demanded (i.e. adopted and used) by large numbers of households throughout the developing world. Four priority areas for future research are: (1) improving information on dose-response relationships between indoor air pollution and various health effects (e.g. increased mortality and morbidity risks); (2) improving information on impacts from interventions in terms of air pollution reductions and also cooking times, fuel use, and heat intensities; (3) improving information on household shadow values for improved health, with separate information for adult and child health; and (4) considering more directly household information, and its adequacy, for their ability to evaluate the relationships between fuel use and health.

Adult↗
PubMed1987

Industrial pollution with copper and other heavy metals in a beef cattle ranch.

Experimental evidence of air borne heavy metal pollution as the cause of a disease of unknown etiology in beef cattle was obtained. Analysis of metals in natural grasses and leaves of tree defined Cu, Zn and Pb as the major pollutants, with Cd being a minor one. Emissions from a Cu smelter were traced as the main source of metallic pollution. No evidence of metal accumulation in the soil was found, mainly because of the short duration and intermittent pattern of pollution. A progressive intake of the several heavy metals contained in dusts deposited on the grasses was considered the cause of the sickness; this was associated with the grazing of cattle on contaminated grasses. The most severe cases were found in the most polluted pastures. Excepting Cd, the concentrations of the metals in the livers and kidneys of affected cattle were high. No overlapping of the respective ranges between test and control samples from both organs was found. Mean hepatic levels of Cu (925.7 mg/kg DM), Zn (491.2 mg/kg) and Pb (26.7 mg/kg) reflected the decreasing order of the concentrations of these elements in the polluted grasses. The main clinical and pathological features of this disease were discussed in light of the organic levels of the investigated metals. Disease could not be ascribed to a pure chronic toxicosis with any one of these.

Animals↗
PubMed1998

Cultural concerns regarding contaminants in Alaskan local foods.

Indigenous people of Alaska, who depend in many ways on foods which they obtain locally by hunting, fishing, and gathering, have raised concerns about the changing quality of their foods in light of confirmation of the long-range transport of global pollutants. A review of a variety of parallel research efforts has shown little consistency in practice, no clear evaluation of exposure levels through dietary surveys on a broad scale, and no comprehensive educational effort to inform the general public of the changing levels of pollutants in local foods. Nor has there been adequate communication regarding the source of the contamination, whether natural contaminants or anthropogenic pollution. Alaska Native cultural issues that contribute to the risk perception of a health problem inherent in eating a traditional diet that is showing signs of increasing levels of pollution, no matter how small, must be considered in any recommendations regarding locally obtained foods and in public health efforts. Recommended cross-cultural communication methods should be employed in dealing with topics of high community concern.

Alaska↗
PubMed1970

Polynuclear aromatic hydrocarbons in the water environment.

Many polynuclear aromatic hydrocarbons (PAH) are known to be carcinogenic to animals and probably to man. This review is concerned with carcinogenic and non-carcinogenic PAH in the water environment, with emphasis on 3,4-benzpyrene (BP) because it is ubiquitous, is one of the most potent of the carcinogenic PAH and has been widely studied. Although PAH are formed in combustion and other high-temperature processes, there is also evidence for their endogenous formation in plants, which may explain their ubiquity therein. Although the solubility of these compounds in pure water is very low, they may be solubilized by such materials as detergents, or they may otherwise occur in aqueous solution associated with or adsorbed on to a variety of colloidal materials or biota, and thereby be transported through the water environment. A notable characteristic of PAH is their sensitivity to light.PAH have been found in industrial and municipal waste effluents, and occur in soils, ground waters and surface waters, and their sediments and biota. With the exception of filtration or sorption by activated carbon, conventional water treatment processes do not efficiently remove them, and they have been found in domestic water supplies. Because of the ubiquity of PAH in the environment, it is impossible to prevent completely man's exposure to them; nevertheless their surveillance should be continued and their concentrations in the environment should be reduced where practicable.

Air Pollution↗
PubMed1978

Studies on atmospheric pollens in the Philippines.

The predominant pollen in the Philippines is the grass pollen, followed by Mimosa, Moraceae, Cyperaceae, lower vascular plants spores, Amaranth, Coconut, Tiliaceae, Pinus, Compositae and Alnus (in decreasing order of significance). The atmospheric pollen pollution in Quezon City is heavy in November, December and January; in Los Banos during January, February, March, April, June and November; and in Baguio City during February, March, April and May. Compared to the density of pollution in these areas, the incidence of pollen pollution in Bacolod City, Davao City and Naga City is very light.

Allergens↗
PubMed2005

Atmospheric transformation of diesel emissions.

This paper reviews the major physical and chemical transformation the primary diesel emissions undergo during dispersion and transport in the atmosphere. Since diesel emissions contain compounds that are present in other combustion source's emissions, their atmospheric transformations are not specific to this source category only. The most important chemical reactions of diesel exhaust constituents are with OH radicals, followed by ozone, NO3 radicals and light. While data now exists concerning the chemical and physical nature and the inventory of diesel emissions, our knowledge concerning the products of their chemical transformations is still limited. In particular, there is currently very little in the literature that addresses the impact of atmospheric transformation on the health effects of inhaled diesel exhaust. As an example of such a study, the design and the preliminary data obtained from the current project executed with the aid of the European Photoreactor (EUPHORE) simulation chamber in Valencia, Spain, is discussed.

Air Movements↗
PubMed1997

Environmental antiandrogens: developmental effects, molecular mechanisms, and clinical implications.

Industrial chemicals and environmental pollutants can disrupt reproductive development in wildlife and humans by mimicking or inhibiting the action of the gonadal steroid hormones, estradiol and testosterone. The toxicity of these so-called environmental endocrine disruptors is especially insidious during sex differentiation and development due to the crucial role of gonadal steroid hormones in regulating these processes. This review describes the mechanism of toxicity and clinical implications of a new class of environmental chemicals that inhibit androgen-mediated sex development. For several of these chemicals, including the agricultural fungicide vinclozolin and the ubiquitous and persistent 1,1,1-trichloro-2,2-bis (p-chlorophenyl)ethane metabolite, 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene, the molecular mechanism of action and the adverse developmental effects on male sex differentiation have been elucidated and are used as examples. Environmental chemicals with antiandrogenic activity offer profound implications with regard to recent clinical observations that suggest an increasing incidence of human male genital tract malformations, male infertility, and female breast cancer. Finally, in light of increasing concern over the potential endocrine disrupting effects of environmental pollutants, an in vitro/in vivo investigational strategy is presented which has proved useful in identifying chemicals with antiandrogen activity and their mechanism of action.

Androgen Antagonists↗
PubMed2005

Photosensitized oxidation of substituted phenols on aluminum phthalocyanine-intercalated organoclay.

Bentonite modified with cationic surfactant, cetyltri-methylammonium bromide (CTMA), was an effective sorbent for organic pollutants in water. To make the sorbent recyclable, aluminum phthalocyanine (AIPc), a representative photosensitizer for generation of singlet oxygen, was inserted successfully into the interlamellar space of CTMA-modified bentonite. Under visible light (lambda > 450 nm) irradiation, the composite catalyst exhibited a remarkable activity for degradation of the recalcitrant pollutants phenol, 4-chlorophenol, 4-nitrophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol in an aerated aqueous medium. The initial rate of the heterogeneous photoreaction was found to increase with the initial amount of the substrate sorption onto the catalyst, the kinetics following the Langmuir-Hinshelwood equation. Loading of AIPc into the organoclay led to slight expansion of the clay basal spacings from 1.82 to 2.15 nm, but the sorption capacity was decreased notably. The optimal loading of AIPc was about 0.25 wt %. The result demonstrates thatthe surfactant-modified bentonite not only offers a hydrophobic zone for enrichment of organic contaminants but also provides a flexible environment for destruction of the sorbed pollutants by singlet oxygen generated in situ. It was noted, however, that during four repeated experiments, both the sorption and the degradation rate of 2,4,6-trichlorophenol were gradually decreased, due to some intermediates formed and sorbed onto the catalyst surface.

Aluminum↗
PubMed2002

Is the trachea a marker of the type of environmental pollution?

OBJECTIVES/HYPOTHESIS: The differentiated character of changes in the mucous relief of the trachea as induced by air containing pollutants from the wastes of nickel-, mercury-, and cement-producing plants and by Candida albicans occurring in the waste disposal site of a large town are identified. The trachea was chosen because it is the entrance gate for the penetration of polluted air into the lungs. Changes on the trachea influence the character and extent of changes in lungs. STUDY DESIGN: Histological study with Viennese grey strain laboratory rabbits and rats caught directly on an investigated site. METHODS: We present new results of the functional morphology of the respiratory system as the results of scanning and transmission electron microscopy studies that can reveal character and range of damage of mucosal relief of trachea relevant to the functional dynamics of mucociliary clearance. Under physiological conditions this mechanism allows that only respirable dust particles enter the deep respiratory tract. RESULTS: In case of a damaged tracheal relief because of exposure to various aerosols, the functional morphology is changed, which aids in understanding the mechanisms damaging to mucociliary clearance induced by living in heavily polluted areas. CONCLUSION: Understanding of these morphological changes on base of detailed electron microscopic findings sheds new light on elaborating novel diagnostic methods for clinical practice.

Air Pollutants↗
PubMed1980

Automobile inspection and maintenance programs: their role in reducing air pollution.

The development of Inspection and Maintenance Programs to control automobile emissions are one component of a comprehensive strategy to reduce automobile related air pollutants such as CO, NOX, and HC. Since the efficiency at which most motored vehicles are designed to limit pollutant emissions deteriorate with prolonged driving, an Inspection and Maintenance system is needed to restore the ability of the automobile to achieve its designed emission standards. Several types of approaches toward developing Inspection and Maintenance Programs in the U.S. including city, county, and state levels of organization and their effectiveness have been described. However, information on the efficiency of these approaches in achieving reductions in pollutant levels remain to be documented, as well as the cost effectiveness of such programs, and their acceptance by the public. In light of the important role that Inspection and Maintenance Programs have been projected to have in the U.S. in reducing automobile related air pollution, it is recommended that interdisciplinary research projects evaluating the multiple dimensions of Inspection and Maintenance Programs be initiated.

Air Pollution↗
PubMed1978

Protective role of ascorbic acid in fishes exposed to organochlorine pollution.

Protective role of ascorbic acid on the toxic effect of aldrin pollution in an air-breathing fish Channa punctatus Bloch is reported. Fishes fed with aldrin mixed diet at 0.25% showed 25% mortality in 30 days. Mortality is preceded by certain changes in peripheral blood such as polycythemia and leucocytosis with increased thrombocyte but decreased neutrophil population. However, a massive dose of ascorbic acid (500 mg/100 g diet) was found to considerably neutralize the toxic effect as evidenced by 10-fold decrease in mortality and significantly lowered haematological response. The significance of these studies in the light of physiological role of ascorbic acid as a micronutrient for protection against pollution stress is discussed.

Aldrin↗
PubMed1995

Review of recent studies from central and Eastern Europe associating respiratory health effects with high levels of exposure to "traditional" air pollutants.

The serious environmental problems caused by decades of Communist mismanagement of natural resources in countries of Central and Eastern Europe have been brought to light in recent years. All environmental media, including air, water, food, and soil have been burdened with toxic chemicals. Large segments of the population have been, and are now being exposed to air pollution levels exceeding guidelines established by western countries and by international health organizations. This review focuses on epidemiologic evidence regarding health effects of poor air quality in Central and Eastern Europe. It appears that short-term high levels of air pollutants (primarily particulates and SO2) may increase mortality in sensitive parts of the population. Associations were also seen between air pollution levels and prevalence of respiratory diseases as well as lung function disturbances in adults and children. One study indicated that urban air pollution increased the risk of lung cancer. Several investigations pointed to strong interactions between risk factors. The poor scientific standard of the studies often makes it difficult to evaluate the findings. Several steps should be taken to develop environmental epidemiology in Central and Eastern Europe, including international collaboration in research projects and training.

Air Pollutants↗
PubMed2004

Micro-spatial variation of soil metal pollution and plant recruitment near a copper smelter in Central Chile.

Soil chemical changes produced by metal smelters have mainly been studied on a large scale. In terms of plant survival, determination of small scale variability may be more important because less toxic microhabitats may represent safe sites for successful recruitment and thus for plant survival. Three dominant microhabitats (open spaces and areas below the canopy of Sphaeralcea obtusiloba and Baccharis linearis shrubs) were defined in a heavily polluted area near a copper smelter and characterised in terms of microclimate, general soil chemistry, total and extractable metal concentrations in the soil profile (A0 horizon, 0-5 and 15-20 cm depth), and seedling densities. Results indicated a strong variability in microclimate and soil chemistry not only in the soil profile but also among microhabitats. Air/soil temperatures, radiation and wind speed were much lower under the canopy of shrubs, particularly during the plant growth season. Soil acidification was detected on top layers (0-5 cm depth) of all microhabitats while higher concentrations of N, Cu and Cd were detected on litter and top soil layers below shrubs when compared to open spaces; however, high organic matter content below shrubs decreased bioavailability of metals. Plant recruitment was concentrated under shrub canopies; this may be explained as a result of the nursery effect exerted by shrubs in terms of providing a more favourable microclimate, along with better soil conditions in terms of macronutrients and metal bioavailability.

Biological Availability↗
PubMed2006

Formation of estrogenic products from environmental phthalate esters under light exposure.

Phthalate esters (PEs) have been suspected to be environmental endocrine disruptors and the detailed mechanism remains unclear. The activities of these chemicals can be enhanced through chemical modification under the environmental conditions. We demonstrate that PEs acquire unequivocal estrogenic activity by light exposure. Through UV exposure of an aqueous PE solution, one active photoproduct, identified as 4-hydroxyPE (PE-4OH) based on its characteristic UV and mass spectra, was detected in an estrogen receptor alpha-dependent transactivation assay. PE-4OH was effectively generated by UV 290 nm. The PE-4OH production accompanied H2O2 generation in a UV dose-dependent manner. Both PE and UV irradiation were indispensable in the generation of H2O2. Addition of H2O2 to the PE solution increased PE-4OH production under UV irradiation. The PE-4OH production was also observed in the PE reaction with the Fenton reagent generating hydroxyl radical without UV irradiation. The proposed mechanism for PE-4OH production based on these results is such that by PE-mediated photosensitization H2O2 is generated from O2 and H+ and decomposed to hydroxyl radical, thus oxidizing the PE benzene ring. The PEs-4OH are remarkably active estrogenic products of PEs and would be involved in ER-mediated endocrine disruption.

Chromatography, High Pressure Liquid↗
PubMed2006

Comparison of oxidative properties, light absorbance, total and elemental mass concentration of ambient PM2.5 collected at 20 European sites.

OBJECTIVE: It has been proposed that the redox activity of particles may represent a major determinant of their toxicity. We measured the in vitro ability of ambient fine particles [particulate matter with aerodynamic diameters<or=2.5 microm (PM2.5)] to form hydroxyl radicals (.OH) in an oxidant environment, as well as to deplete physiologic antioxidants (ascorbic acid, glutathione) in the naturally reducing environment of the respiratory tract lining fluid (RTLF). The objective was to examine how these toxicologically relevant measures were related to other PM characteristics, such as total and elemental mass concentration and light absorbance. DESIGN: Gravimetric PM2.5 samples (n=716) collected over 1 year from 20 centers participating in the European Community Respiratory Health Survey were available. Light absorbance of these filters was measured with reflectometry. PM suspensions were recovered from filters by vortexing and sonication before dilution to a standard concentration. The oxidative activity of these particle suspensions was then assessed by measuring their ability to generate .OH in the presence of hydrogen peroxide, using electron spin resonance and 5,5-dimethyl-1-pyrroline-N-oxide as spin trap, or by establishing their capacity to deplete antioxidants from a synthetic model of the RTLF. RESULTS AND CONCLUSION: PM oxidative activity varied significantly among European sampling sites. Correlations between oxidative activity and all other characteristics of PM were low, both within centers (temporal correlation) and across communities (annual mean). Thus, no single surrogate measure of PM redox activity could be identified. Because these novel measures are suggested to reflect crucial biologic mechanisms of PM, their use may be pertinent in epidemiologic studies. Therefore, it is important to define the appropriate methods to determine oxidative activity of PM.

Air Pollutants↗
PubMed1978

Phagocytosis by sheep alveolar macrophages: relationship between opsonin concentration and light emission in the presence of luminol.

The observations reported may be applied to determining the effects of various compounds, e.g., environmental pollutants and agricultural chemicals, upon the phagocytic activity of alveolar macrophages, and the method described will aid in detecting compounds which alter Fc receptor activity. A direct linear relationship existed between the concentration of antibody used to opsonize bacterial particles and the quantity of luminol-dependent light emitted by a population of sheep alveolar macrophages exposed to the opsonized particles. The relationship can be illustrated with a Lineweaver-Burk-style double-reciprocal plot. An analogy is suggested between the kinetics of enzyme substrate reactions and the interaction of antibody-coated particles with Fc receptors on cell membranes.

Animals↗