SEARCH · PubMed Health

Results for “Particulate Matter”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 1,549 records · Page 86Linked to original sources

PubMed2000

Particle concentrations in urban microenvironments.

Although ambient particulate matter has been associated with a range of health outcomes, the health risks for individuals depend in part on their daily activities. Information about particle mass concentrations and size distributions in indoor and outdoor microenvironments can help identify high-risk individuals and the significant contributors to personal exposure. To address these issues in an urban setting, we measured particle count concentrations in four size ranges and particulate matter (3/4) 10 microm (PM(10)) concentrations outdoors and in seven indoor microenvironments in Boston, Massachusetts. Particle counts and PM(10) concentrations were continuously measured with two light-scattering devices. Because of the autocorrelation between sequential measurements, we used linear mixed effects models with an AR-1 autoregressive correlation structure to evaluate whether differences between microenvironments were statistically significant. In general, larger particles were elevated in the vicinity of significant human activity, and smaller particles were elevated in the vicinity of combustion sources, with indoor PM(10) concentrations significantly higher than the outdoors on buses and trolleys. Statistical models demonstrated significant variability among some indoor microenvironments, with greater variability for smaller particles. These findings imply that personal exposures can depend on activity patterns and that microenvironmental concentration information can improve the accuracy of personal exposure estimation.

Air Pollutants↗

PubMed2002

Use of the green fluorescent protein to monitor the fate of Serratia entomophila causing amber disease in the New Zealand grass grub, Costelytra zealandica.

A series of constitutive green fluorescent protein (pGFPuv) derivatives of the bacterium Serratia entomophila (Enterobacteriaceae) were constructed, allowing the fate of cells causing amber disease ingested by the New Zealand grass grub (Costelytra zealandica, Coleoptera: Scarabaeidae) to be monitored. Examination of tissue and contents of the alimentary tract over time from ingestion, under fluorescence microscopy, revealed that the major site of S. entomophila colonisation in the grass grub is intestinal particulate matter. Visual examinations showed that wild type pathogenic strain persisted in high numbers in the grass grub intestinal tract, notably in the area of the hindgut, but the S. entomophila pADAP-free strain 5.6RC and the pADK mutant derivatives (pADK-4, -10, -13) that gave a non-feeding without gut clearance phenotype, were unable to colonise the gut. The indiscriminate colonisation of the intestinal tract particulate matter by pathogenic bacteria, rather than the colonisation of a specific site of activity, suggests that the bacterial toxins are induced and released from the bacteria while they live freely in the grass grub intestinal tract.

Animals↗

PubMed2001

Canines as sentinel species for assessing chronic exposures to air pollutants: part 1. Respiratory pathology.

A complex mixture of air pollutants is present in the ambient air in urban areas. People, animals, and vegetation are chronically and sequentially exposed to outdoor pollutants. The objective of this first of 2 studies is to evaluate by light and electron microscopy the lungs of Mexico City dogs and compare the results to those of 3 less polluted cities in MEXICO: One hundred fifty-two clinically healthy stray mongrel dogs (91 males/61 females), including 43 dogs from 3 less polluted cities, and 109 from southwest and northeast metropolitian Mexico City (SWMMC, NEMMC) were studied. Lungs of dogs living in Mexico City and Cuernavaca exhibited patchy chronic mononuclear cell infiltrates along with macrophages loaded with particulate matter (PM) surrounding the bronchiolar walls and extending into adjacent vascular structures; bronchiolar epithelial and smooth muscle hyperplasia, peribronchiolar fibrosis, microthrombi, and capillary and venule polymorphonuclear leukocytes (PMN) margination. Ultrafine PM was seen in alveolar type I and II cells, endothelial cells, interstitial macrophages (Mtheta), and intravascular Mtheta-like cells. Bronchoalveolar lavage showed significant numbers of alveolar macrophages undergoing proliferation. Exposure to complex mixtures of pollutants-predominantly particulate matter and ozone-is causing lung structural changes induced by the sustained inflammatory process and resulting in airway and vascular remodeling and altered repair. Cytokines released from both, circulating inflammatory and resident lung cells in response to endothelial and epithelial injury may be playing a role in the pathology described here. Deep concern exists for the potential of an increasing rise in lung diseases in child populations exposed to Mexico City's environment.

Age Distribution↗

PubMed1978

The effect of shear, specific surface, and air interface on the development of blood emboli and hemolysis.

Heparinized dog blood was exposed to shear and foreign surfaces in conicylindrical test cells. The cells were injection molded from polycarbonate and were filled using a technique that avoided contact of the blood with air. Particulate-matter formation was measured and was found to be dominated by the surface-to-blood-volume ratio and to be independent of shear rate. Hemolysis was also measured and was found to vary linearly with shear rate and to increase with increasing surface-to-blood volume ratio. Thus, at low shear rates and high specific surface conditions, the degree of hemolysis was found to be minimal while particulate-matter formation was high. The results suggest that the safety of extracoporeal perfusion procedures cannot be inferred from hemolysis measurements alone. In one series of tests, a gas-blood interface was generated at a rate equivalent to the rate of surface renewal in conventional disc oxygenators. The gas-blood interface failed to contribute significantly to the damage indices, which suggests that the apparent superiority of membrane oxygenators may be a result of factors other than the absence of a blood-gas interface.

Biomechanical Phenomena↗

PubMed2006

Air sampling with Empore solid phase extraction membranes and online single-channel desorption/liquid chromatography/mass spectrometry analysis: determination of volatile and semi-volatile organophosphate esters.

A method for determining organophosphate esters in air samples using C8 Empore solid phase extraction (SPE) membranes has been developed. After the sampling the analytes trapped in the membrane are completely desorbed with methanol, using an extraction cell connected online to the organic modifier channel of a HPLC gradient pump. The addition of water to the mobile phase prior to analytical chromatography ensures that the analytes are refocused and efficiently separated. Sampling with Empore SPE membranes enables the collection of analytes in both the vapour phase and particulate matter. During the air sampling procedure no losses were observed after 24 h of sampling, yielding a total volume of 14.4 m3, even for the most volatile compound used in this investigation (trimethylphosphate). Complete desorption was observed for all the organophosphate esters and recoveries were greater than 95%, with a relative standard deviation of less than 8%. The limits of detection ranged between 0.4 and 19 pg/m3. The effect of particulate matter on the extraction efficiency was investigated in detail by spiking the membranes with reference standard material. It was also found that the SPE membranes could be stored for at least 5 days at room temperature without any evidence of loss. The efficacy of the method was verified using real samples from different common indoor environments. Interestingly, significant quantities of several phosphate esters were found in a NIST standard reference material (urban dust, SRM 1649a).

Air Pollutants↗

PubMed2000

Export of mercury downstream from reservoirs.

Environmental effects monitoring at the La Grande hydroelectric complex (Québec, Canada) revealed important increases in mercury levels in fish caught downstream from reservoirs. A study was carried out in 1997 immediately below the Caniapiscau Reservoir to identify by which components mercury is transported downstream from reservoirs and to assess the amount of mercury being exported. Stomach contents of lake whitefish (Coregonus clupeaformis) captured immediately below the Caniapiscau Reservoir were examined to determine which components transfer mercury from lower trophic levels to fish. The analyses of water samples and drifting organisms collected below the reservoir indicate that the dissolved fraction (< 0.45 microm) and the suspended particulate matter (0.45-50 microm) are the major components by which methylmercury is transferred downstream of reservoirs, accounting for 64 and 33%, respectively, of the total amounts exported. Drifting organisms such as plant debris, benthic invertebrates, fish, phytoplankton and zooplankton are much less important pathways for mercury export because of their very low biomass per water volume coming out of the generating station, as opposed to the high biomass of suspended particulate matter. However, zooplankton is the major component by which methylmercury is directly transferred to non-piscivorous fish downstream.

Animals↗

PubMed2005

Temporal variability in physical speciation of metals during a winter rain-on-snow event.

Particulate matter in urban rivers transports a significant fraction of pollutants, changes rapidly during storm events, and is difficult to characterize. In this study, the physical speciation of trace metals and organic C in an urban river and upstream headwaters site in Torrington, CT, were measured during a winter rain-on-snow event. In addition, a selective fractionation scheme, using membrane and tangential-flow ultrafiltration methods to separate suspended particulate matter into sand, silt, clay, and colloid fractions, was evaluated based on the appropriateness of the chosen size categories. During peak runoff at the urban river site, total-recoverable concentrations of the metals Cu and Pb increased 6- and 13-fold to 16.9 and 9.5 microg L(-1), respectively, compared with baseflow concentrations. Concentrations of Cu and Pb reached only 0.9 and 0.86 microg L(-1) at the headwaters site. For the measured storm event, the majority of metals were transported by the urban river in association with coarse silt (20-80 microm particle diam.) during peak runoff. During peak runoff at the urban site, organic C associated with the large colloid fraction (0.1-1.0 microm) increased from 5% (at baseflow) to 54% of the total C in transport, whereas dissolved organic C and that associated with smaller colloids decreased from 91.5% (at baseflow) to 41% of the total. Other elements that were monitored as part of the study were Na, K, Ca, Mg, Fe, Mn, Al, Cd, Cl-, NO3(-), and SO4(2-). The chosen fractionation scheme was useful to characterize pollutant transport during this event, but further testing should be undertaken to determine the most appropriate size range categories, and to ensure that the sizes measured are comparable to those used in other studies.

Connecticut↗

PubMed1998

Nasal epithelium as a sentinel for airborne environmental pollution.

A wide range of chemicals, particulate matter, and gaseous air pollutants are present in urban atmospheres and may pose a significant health risk for human populations. Nasal passages are the first site of contact of the respiratory tract with the environment and offer significant protection to the lower respiratory tract by conditioning the inspired air. This activity, which includes removal of certain pollutants, places the nose at risk of pathological changes, including cancer. Mexico City residents are exposed to a complex mixture of air pollutants. Based on predicted nasal air flow characteristics, four nasal biopsy sites were selected for study in adult male volunteers from a control low polluted town (n = 12) and southwest metropolitan Mexico City permanent residents (n = 54). Clinical data with emphasis on nasal symptoms and histopathological changes including basal and goblet cell hyperplasia, squamous metaplasia, epithelial dysplasia, and neovascularization were evaluated. Immunohistochemical staining was used to assess accumulation of p53 protein. Control individuals had no respiratory symptoms and their biopsies were unremarkable. Mexico City residents complained of epistaxis, rhinorrea, nasal crusting, dryness, and nasal obstruction. Their biopsies showed patchy shortening of cilia, deciliated areas, basal cell hyperplasia, and squamous metaplasia. Dysplastic lesions were predominantly located on antral squamous epithelium and in squamous metaplastic epithelium of the posterior inferior turbinates and they exhibited p53 nuclear accumulation. Individuals with > 10 h of daily outdoor exposure for 5 years or more had the highest rate of dysplasia. Subjects with epistaxis were more likely to have dysplasias and neovascularization. Results of this study suggest: (a) Nasal lesions in Mexico City residents are likely the result of many potentially toxic and/or carcinogenic pollutants, including ozone, aldehydes, particulate matter, and unmeasured pollutants; (b) the alteration of the nasal mucociliary defense mechanisms and the effects of reactive and/or water-soluble materials and particulates could be playing a major role in the nasal pathology; (c) the accumulation of p53 protein in dysplastic nasal lesions in the context of prolonged exposure to air pollutants raises the possibility that p53 mutations are already present and are providing the squamous cells with a selective advantage for clonal expansion; and (d) the nasal passages provide a valuable sentinel tissue for the detection of toxic air pollutants.

Adult↗

PubMed2003

Investigation of mainstream smoke aerosol of the argileh water pipe.

A first-generation smoking machine and protocol have been developed in order to study the mainstream smoke aerosol and elucidate thermal-fluid processes of the argileh water pipe. Results using a common mo'assel tobacco mixture show that, contrary to popular perceptions, the mainstream smoke contains significant amounts of nicotine, "tar" and heavy metals. With a standard smoking protocol of 100 puffs of 3 s duration spaced at 30-s intervals, the following results were obtained in a single smoking session: 2.25 mg nicotine, 242 mg nicotine-free dry particulate matter (NFDPM), and relative to the smoke of a single cigarette, high levels of arsenic, chromium and lead. It was found that increasing puff frequency increased the NFDPM but had little effect on nicotine delivery, while removing the water from the bowl increased by several-fold the nicotine, but had little effect on NFDPM. It was also found that the charcoal disk heat source contributed less than 2% of total particulate matter (TPM), and that characteristic temperatures of the tobacco varied from 450 degrees C nearest the heat source to 50 degrees C furthest away, indicating that the NFDPM is likely a result of devolatilization rather than chemical reaction, and will thus differ significantly in composition from that of cigarette smoke.

Aerosols↗

PubMed2005

Disruption of iron homeostasis as a mechanism of biologic effect by ambient air pollution particles.

Several features of the clinical presentation and changes in physiology and pathology following exposure to many diverse ambient air pollution particles are comparable, suggesting a common mechanism for their biological effect. We propose that a mechanism of biological effect common to many ambient air pollution particles is a disruption of iron homeostasis in cells and tissues. Among traits shared by every particle-related lung injury is the introduction of a solid-liquid interface into the respiratory tract. All surfaces of particulate matter have some concentration of oxygen-containing functional groups. As a result of its electropositivity, Fe(3+) has a high affinity for oxygen-donor ligands and will react with these groups at the particle surface. Retained particles accumulate metal from available sources in a cell and tissue, and this complexed iron mediates oxidant generation. In addition to complexation onto the solid-liquid interface provided by the surface of particulate matter (PM), there are several alternative pathways by which metal homeostasis in the lower respiratory tract can be disrupted following exposure to ambient air pollution particles to affect an oxidative stress. Evidence suggests that disruption in iron homeostasis following exposures to ambient air pollution particles is an initial event in their biological effect. An association between metal equilibrium in the lower respiratory tract and biological effect in the lung could explain the observed differential toxicity of ultrafine, fine, and coarse particles and disparities in host susceptibility.

Air Pollutants↗

PubMed1977

[The determination of resort and stress-areas by air pollution 1. Communication: health effects, methods, emission inventories (author's transl)].

The Alps and other mountainous areas are air-hygene problem zones: By distadvantageous geographical and meteorological conditions relativ small emissions can be the reason of high concentration of air pollutants in the ambient air. Therefore the separation of different stress zones by the air quality is an important data for land use planning with regards on health. Different methods which are internationally usual can not be used in mountainous areas (e.g., dispersion models, calculation according to the TAL). A method is introduced for determination and separation of the level of SO2 and particulate matter in a spreadout area which can be used also in complex terrain. This method was proved in air pollution studies in areas with more than 30000 km2 over four years. The investigations were based on a combination of emissions studies, measurements of immissions by continous working SO2 monitoring instruments, lead dioxide candles and Bergerhoff-instruments, and--if possible--meteorological investigations. Report 1 describes the health effects of SO2 and particulate matter, the used tentative methods (analysis for dustfall, the sulfation rate by lead dioxide candles, analysis for sulfur dioxide content by conductimetric and coulometric methods), the emission inventories and the net works.

Air Pollution↗

PubMed2004

Carbon monoxide concentration forecasting in Santiago, Chile.

In the city of Santiago, Chile, air quality is defined in terms of particulate matter with an aerodynamic diameter < or = 10 microm (PM10) concentrations. An air quality forecasting model based on past concentrations of PM10 and meteorological conditions currently is used by the metropolitan agency for the environment, which allows restrictions to emissions to be imposed in advance. This model, however, fails to forecast between 40 and 50% of the days considered to be harmful for the inhabitants every year. Given that a high correlation between particulate matter and carbon monoxide (CO) concentrations is observed at monitoring stations in the city, a model for CO concentration forecasting would be a useful tool to complement information about expected air quality in the city. Here, the results of a neural network-based model aimed to forecast maximum values of the 8-hr moving average of CO concentrations for the next day are presented. Forecasts from the neural network model are compared with those produced with linear regressions. The neural network model seems to leave more room to adjust free parameters with 1-yr data to predict the following year's values. We have worked with 3 yr of data measured at the monitoring station located in the zone with the worst air quality in the city of Santiago, Chile.

Air Pollutants↗

PubMed2005

Home environmental intervention in inner-city asthma: a randomized controlled clinical trial.

BACKGROUND: Airborne pollutants and indoor allergens increase asthma morbidity in inner-city children; therefore, reducing exposure, if feasible, should improve asthma morbidity. OBJECTIVE: To conduct a randomized controlled trial of methods to reduce environmental pollutant and allergen exposure in the homes of asthmatic children living in the inner city. METHODS: After the completion of questionnaires, spirometry and allergen skin tests, home inspection, and measurement of home air pollutant and allergen levels, 100 asthmatic children aged 6 to 12 years were randomized to the treatment group (home-based education, cockroach and rodent extermination, mattress and pillow encasings, and high-efficiency particulate air cleaner) or to the control group (treated at the end of the 1-year trial). Outcomes were evaluated by home evaluations at 6 and 12 months, clinic evaluation at 12 months, and multiple telephone interviews. RESULTS: In the treatment group, 84% received cockroach extermination and 75% used the air cleaner. Levels of particulate matter 10 microm or smaller declined by up to 39% in the treatment group but increased in the control group (P < .001). Cockroach allergen levels decreased by 51% in the treatment group. Daytime symptoms increased in the control group and decreased in the treatment group (P = .04). Other measures of morbidity, such as spirometry findings, nighttime symptoms, and emergency department use, were not significantly changed. CONCLUSIONS: A tailored, multifaceted environmental treatment reduced airborne particulate matter and indoor allergen levels in inner-city homes, which, in turn, had a modest effect on morbidity.

Air Pollution, Indoor↗

PubMed2004

Designated "no smoking" areas provide from partial to no protection from environmental tobacco smoke.

OBJECTIVE: To determine the efficacy of designated "no smoking" areas in the hospitality industry as a means of providing protection from environmental tobacco smoke (ETS), and whether certain design features assist in achieving this end. METHODOLOGY: In the greater metropolitan region of Sydney, a representative group of 17 social and gaming clubs, licensed to serve alcoholic beverages and in which, apart from designated areas, smoking occurs, agreed to participate. In each establishment, simultaneous single measurements of atmospheric nicotine, particulate matter (10 microm; PM10) and carbon dioxide (CO2) levels were measured in a general use area and in a designated "no smoking" area during times of normal operation, together with the levels in outdoor air (PM10 and CO2 only). Analyses were made of these data to assess the extent to which persons using the "no smoking" areas were protected from exposure to ETS. RESULTS: By comparison with levels in general use areas, nicotine and particulate matter levels were significantly less in the "no smoking" areas, but were still readily detectable at higher than ambient levels. For nicotine, mean (SD) levels were 100.5 (45.3) microg/m3 in the areas where smoking occurred and 41.3 (16.1) microg/m3 in the "no smoking" areas. Corresponding PM10 levels were 460 (196) microg/m3 and 210 (210) microg/m3, while outdoor levels were 61 (23) microg/m3. The reduction in pollutants achieved through a separate room being designated "no smoking" was only marginally better than the reduction achieved when a "no smoking" area was contiguous with a smoking area. CO2 levels were relatively uninformative. CONCLUSION: Provision of designated "no smoking" areas in licensed (gaming) clubs in New South Wales, Australia, provides, at best, partial protection from ETS-typically about a 50% reduction in exposure. The protection afforded is less than users might reasonably have understood and is not comparable with protection afforded by prohibiting smoking on the premises.

Air Pollutants↗

PubMed2000

Are there sensitive subgroups for the effects of airborne particles?

Recent studies have shown that particulate air pollution is a risk factor for hospitalization for heart and lung disease; however, little is known about what subpopulations are most sensitive to this pollutant. We analyzed Medicare hospital admissions for heart disease, chronic obstructive pulmonary disorders (COPD) and pneumonia in Chicago, Cook County, Illinois, between 1985 and 1994. We examined whether previous admissions or secondary diagnoses for selected conditions predisposed persons to having a greater risk from air pollution. We also considered effect modification by age, sex, and race. We found that the air-pollution-associated increase in hospital admissions for cardiovascular diseases was almost doubled in subjects with concurrent respiratory infections. The risk was also increased by a previous admission for conduction disorders. For COPD and pneumonia admissions, diagnosis of conduction disorders or dysrhythmias increased the risk of particulate matter < 10 microm in aerodynamic diameter (PM(10))-associated admissions. Persons with asthma had twice the risk of a PM(10)-associated pneumonia admission and persons with heart failure had twice the risk of PM(10)-induced COPD admissions. The PM(10) effect did not vary by sex, age, and race. These results suggest that patients with acute respiratory infections or defects in the electrical control of the heart are a risk group for particulate matter effects.

Aged↗

PubMed1999

Capillary electrophoresis for trace metal ion analysis in environmental studies.

A new buffer system consisting of 30 mM hydroxylamine hydrochloride, 0.1 mM 1,10-phenanthroline, 1% methanol and pH 3.7 was optimized for simultaneous determination of water and acid leachable metals from respirable, fine and coarse air particulate matters. A reducing environment was used to resolve metal ions with variable oxidation states. A suitable counteranion was employed to enable acidic pH to be used and methanol was added to improve the resolution of the electropherograms and to achieve simultaneous determination of several metal ions. Compared to existing capillary electrophoresis (CE) buffers, the buffer developed, based on direct UV detection of ion-pair with weak interaction, gives improved resolution and sharper, more stable and well-resolved peaks. It detects total irons and solves interfering problems due to the variable oxidation states of iron in environmental samples. Compared to existing mostly alkaline CE buffers for metal analysis, the acidic nature of the buffer system developed makes the pretreatment step simpler and reduces the risk of reagent contamination. Satisfactory working ranges (15-5500 ppb) and detection limits (0.5-3 ppb) were obtained for leachable Zn, Cu, Co, Fe and Cd. The NIST 1648 urban particulate matters were found to leach out 2.53-42.8% water-extractable and 2.76-71.7% acid-extractable Zn, Cu, Fe and Cd. High iron contents, and lower copper and zinc concentrations were found in respirable suspended particulates (RSP) sampled in Hong Kong.

Air Pollutants↗

PubMed2002

Air pollution and health.

The health effects of air pollution have been subject to intense study in recent years. Exposure to pollutants such as airborne particulate matter and ozone has been associated with increases in mortality and hospital admissions due to respiratory and cardiovascular disease. These effects have been found in short-term studies, which relate day-to-day variations in air pollution and health, and long-term studies, which have followed cohorts of exposed individuals over time. Effects have been seen at very low levels of exposure, and it is unclear whether a threshold concentration exists for particulate matter and ozone below which no effects on health are likely. In this review, we discuss the evidence for adverse effects on health of selected air pollutants.

Air Pollutants↗

PubMed2001

Human alveolar macrophage responses to air pollution particulates are associated with insoluble components of coarse material, including particulate endotoxin.

Inhalation of particulate matter in the ambient air has been shown to cause pulmonary morbidity and exacerbate asthma. Alveolar macrophage (AM) are essential for effective removal of inhaled particles and microbes in the lower airways. While some particles minimally effect AM function others inhibit antimicrobial activity or cause cytokine and growth factor production leading to inflammation and tissue remodeling. This study has investigated the effects of water soluble (s) and insoluble (is) components of Chapel Hill, North Carolina ambient particulate matter in the size ranges 0.1-2.5 microm (PM2.5) and 2.5-10 microm (PM10) diameter, on human AM IL-6, TNFalpha, and MCP-1 cytokine production and host defense mechanisms including phagocytosis and oxidant production. Cytokines were found to be induced by isPM10 to a much higher extent (>50-fold) than sPM10, which in turn stimulated production better than isPM2.5, while sPM2.5 was inactive. Previous studies have indicated that endotoxin (ETOX) is a component of sPM10 responsible for cytokine production. Here, it is shown that inhibition of isPM10-induced cytokine production was partially achieved with polymyxin B and LPS-binding protein (LBP), but not with a metal chelator, implicating ETOX as a cytokine-inducing moiety also in isPM10. In addition to inducing cytokines, exposure to isPM10, but not the other PM fractions, also inhibited phagocytosis and oxidant generation in response to yeast. This inhibition was ETOX independent. The decrease in host defenses may be the result of apoptosis in the AM population, which was also found to be specifically caused by isPM10. These results show that the functional capacity of AM is selectively modulated by insoluble components of coarse PM, including the biocontaminant ETOX.

Adolescent↗