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Nitrogen Dioxide (nitrogen + dioxide)
Selected AbstractsChemInform Abstract: Remarkable Effect of Nitrogen Dioxide for N-Hydroxyphthalimide-Catalyzed Aerobic Oxidation of Methylquinolines.CHEMINFORM, Issue 20 2002Satoshi Sakaguchi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Comparison of effects of in vivo nitrogen dioxide exposure starting from different periods on alveolar macrophage activity, assessed by a chemiluminescence technique in Brown-Norway ratsLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2006Takashi Kumae Abstract Nitrogen dioxide (NO2) has been extensively studied for its immune modulating effects on pulmonary cells. Alveolar macrophages (AMs) play an important role in pulmonary immunity. The Brown-Norway (BN) rat has been studied as a high-risk model of allergic diseases. In this study, BN rats were exposed to NO2 from the embryonic or weanling period (EP or WP, respectively). To evaluate the effects of NO2 exposure on pulmonary immunity, the activity levels of rat AMs were assessed as reactive oxygen species-generating capacity, measured by a chemiluminescence (CL) technique, and as cytokine-producing ability. Except for 0.2 ppm of NO2 exposure, the CL responses of AMs obtained from the WP group at 12 weeks old were suppressed significantly. Changes of the cytokine-producing levels suggest that inflammatory reactions are terminated at 12 weeks in the EP group. Correlations between the CL responses and the cytokine levels reveal that NO2 exposure may modulate the direction of AM activation. The CL technique is thought to be useful to evaluate changes in AM activity. In this study, the results suggest that, using the high-risk model of allergic diseases, NO2 exposure from the weanling period has stronger effects on AM activity.Copyright © 2006 John Wiley & Sons, Ltd. [source] Influence of Aprotic Solvent on Selectivity of an Amperometric Sensor with Nafion MembraneELECTROANALYSIS, Issue 5 2006B. Chachulski Abstract This paper presents the results of investigation on selectivity of the sulfur dioxide amperometric sensor with Nafion membrane in the presence of carbon monoxide and nitrogen dioxide as the interferents. There have been compared selectivity coefficients, for the sensors containing the following internal electrolytes: solution of sulfuric acid (concentration 5,mol dm,3) in pure water (A) and solution of sulfuric acid (concentration 5,mol dm,3) in mixed solvent dimethylsulfoxide-water with an DMSO: H2O mole ratio of 1,:,2 (B). Values of the selectivity coefficients have been calculated based on the calibration curves. Analysis of both calibration curves and selectivity coefficients plays a significant role in optimization of a working point of a particular sensor. The investigated sensor operates in a three-electrode system, where the working and counter electrodes are vacuum sublimation deposited on the membrane surface. [source] Data analysis of environmental air pollutant monitoring systems in EuropeENVIRONMETRICS, Issue 6 2004Kristina Voigt Abstract Public access to information about the environment is being strengthened across Europe. The concept of public's right to information gives the basis for the access to environmental information. In this paper the quality of air pollutant monitoring systems in the 15 European member states is analyzed. For pragmatic reasons only the capitals are looked upon. Comprehensive data on environmental monitoring programs concerning air pollutants like ozone (O3), nitrogen dioxide (NO2), nitrogen oxide (NO), carbon dioxide (CO2) and carbon monoxide (CO), and sometimes suspended dust, benzene and other environmental chemicals are available on the free Internet. As different monitoring information systems exist in the European member states a comparison of these systems with their pros and cons is of great interest to the public. Environmental air pollutant monitoring systems in the capitals of the 15 EEC member countries (objects) are evaluated by applying 5 evaluation criteria for the differentiation of these systems. The scores run from 0,=,insufficient, 1,=,medium, to 2,=,excellent. Different data-analysis methods will be applied. As order theory is still not sufficiently presented in the scientific literature, a short overview about the so-called Hasse diagram technique and POSAC method is outlined. In several steps the data-matrix is analyzed coming to the conclusion that all methods (additionally PCA is used) identify one criterion as specifically important. Not unexpected, each method has its own advantage. The aim of this data-analysis is the evaluation of the publicly available air quality monitoring systems in Europe with their pros and cons. This might help the interested public to find and understand the information given on the Internet. Furthermore our evaluation approach might give some recommendations for an improvement of the air quality monitoring systems. Copyright © 2004 John Wiley & Sons, Ltd. [source] ,-tocopherol improves impaired physiology of rat type II pneumocytes isolated from experimentally injured lungsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 11 2000B. Müller Background Oxidant stress delivered by nitrogen dioxide (NO2) inhalation impairs the function of extracellular surfactant as well as surfactant phospholipid metabolism in type II pneumocytes. Because protection against oxidant stress is important to normal lung function, the lung contains a variety of antioxidants, including vitamin E. Whether administration of this antioxidant during NO2 inhalation attenuates NO2 -induced alterations in phospholipid metabolism in type II pneumocytes has not been studied. Methods We exposed rats to identical NO2 body doses (720 p.p.m. x h) using continuous, intermittent, or repetitive protocols. During exposure periods, the animals received daily intramuscular injections of vitamin E (25 mg kg,1). We isolated type II pneumocytes from NO2 -exposed rats and evaluated them for cell yield and viability, as well as for synthesis and secretion of phosphatidylcholine (PC) as measures of surfactant metabolism. Results The yield of type II pneumocytes was significantly elevated from animals that had been exposed continuously to NO2 whereas in intermittently and repeatedly exposed rats, cell yield was similar to yield from control animals. Viability of the isolated cells was similar in controls and all NO2 exposure protocols. Vitamin E treatment of the NO2 -exposed rats neither changed cell yield nor cell viability. Phospholipid de novo synthesis, as estimated by choline incorporation into PC, was increased most after continuous NO2 inhalation whereas in the other conditions there was only a slight increase. Vitamin E administration further increased phospholipid synthesis; this difference reached statistical significance only in the case of intermittent NO2 exposure. Secretion of phosphatidylcholine from type II cells was only reduced after continuous NO2 inhalation and administration of the antioxidant reduced the impairment. Conclusion Because vitamin E appears to preserve the ability of type II pneumocytes isolated from NO2 -exposed rats to synthesize and secrete surfactant lipid, we conclude that administration of vitamin E may mitigate NO2 -induced lung injury. [source] Synthesis of Indium and Indium Oxide Nanoparticles from Indium Cyclopentadienyl Precursor and Their Application for Gas Sensing,ADVANCED FUNCTIONAL MATERIALS, Issue 7 2003K. Soulantica Abstract Decomposition of the organometallic precursor [In(,5 -C5H5)] in toluene in the presence of methanol (8 vol.-%) at room temperature leads to the immediate formation of aggregates of indium nanoparticles of 15,±,2 nm mean diameter. The aggregates are roughly spherical with a mean size of 400,±,40 nm. The particles were characterized by means of transmission electron and high-resolution transmission electron microscopies (TEM and HRTEM), and X-ray diffraction (XRD) studies indicate that the powder consists of the tetragonal phase of indium. The thermal oxidation in air of these nanoparticles yields well-crystallized nanoparticles of In2O3 with unchanged morphology (aggregates of nanoparticles of 16.6,±,2 nm mean diameter with aggregate mean size of 400,±,40 nm) and without any sign of coalescence. XRD pattern shows that the powder consists of the cubic phase of In2O3. The electrical conductivity measurements demonstrate that this material is highly sensitive to an oxidizing gas such as nitrogen dioxide and barely sensitive to a reducing gas such as carbon monoxide. Its association with SnO2 -based sensors allows the selective detection of carbon monoxide (30 ppm) and sub-ppm amounts of nitrogen dioxide (400 ppb) in a mixture at 21,°C and at a relative humidity of 60,%. [source] Thermochemistry for enthalpies and reaction paths of nitrous acid isomersINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 7 2007Rubik Asatryan Recent studies show that nitrous acid, HONO, a significant precursor of the hydroxyl radical in the atmosphere, is formed during the photolysis of nitrogen dioxide in soils. The term nitrous acid is largely used interchangeably in the atmospheric literature, and the analytical methods employed do not often distinguish between the HONO structure (nitrous acid) and HNO2 (nitryl hydride or isonitrous acid). The objective of this study is to determine the thermochemistry of the HNO2 isomer, which has not been determined experimentally, and to evaluate its thermal and atmospheric stability relative to HONO. The thermochemistry of these isomers is also needed for reference and internal consistency in the calculation of larger nitrite and nitryl systems. We review, evaluate, and compare the thermochemical properties of several small nitric oxide and hydrogen nitrogen oxide molecules. The enthalpies of HONO and HNO2 are calculated using computational chemistry with the following methods of analysis for the atomization, isomerization, and work reactions using closed- and open-shell reference molecules. Three high-level composite methods G3, CBS-QB3, and CBS-APNO are used for the computation of enthalpy. The enthalpy of formation, ,Hof(298 K), for HONO is determined as ,18.90 ± 0.05 kcal mol,1 (,79.08 ± 0.2 kJ mol,1) and as ,10.90 ± 0.05 kcal mol,1 (,45.61 ± 0.2 kJ mol,1) for nitryl hydride (HNO2), which is significantly higher than values used in recent NOx combustion mechanisms. H-NO2 is the weakest bond in isonitrous acid; but HNO2 will isomerize to HONO with a similar barrier to the HONO bond energy; thus, it also serves as a source of OH in atmospheric chemistry. Kinetics of the isomerization is determined; a potential energy diagram of H/N/O2 system is presented, and an analysis of the triplet surface is initiated. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 378,398, 2007 [source] Effects of NO2, CO, O2, and SO2 on oxidation kinetics of NO over Pt-WO3/TiO2 catalyst for fast selective catalytic reduction processINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 10 2006Muhammad Faisal Irfan The selective catalytic reduction rate of NO with N-containing reducing agents can be enhanced considerably by converting a part of NO into NO2. The enhanced reaction rate is more pronounced at lower temperatures by using an equimolar mixture of NO and NO2. The kinetics of NO oxidation over Pt-WO3/TiO2 catalyst has been determined in a fixed-bed reactor with different concentrations of oxygen, nitric oxide, and nitrogen dioxide in the presence of 8% water. It has been found that the reaction is second order with respect to nitric oxide, first order for oxygen with a third-order rate constant. Also, it is found that there is no effect on the reaction order with an addition of NO2, CO, or SO2. It follows the same second order but the reaction rate is found to be changed. It is observed that in the case of NO2 and SO2, the reaction rate tends to decrease, but it increases with the addition of CO into the feed. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 613,620, 2006 [source] Acceleration of nitric oxide autoxidation and nitrosation by membranesIUBMB LIFE, Issue 4-5 2007Matias N. Möller Abstract The reaction between nitric oxide (,NO) and oxygen yields reactive species capable of oxidizing and nitrosating proteins, as well as deaminating DNA bases. Although this reaction is considered too slow to be biologically relevant, it has been shown that membranes, lipoproteins, mitochondria and possibly proteins can accelerate this reaction. This effect stems from the higher solubility of both ,NO and O2in the hydrophobic phase of these biological particles, leading to a concentration of both reagents and so a higher rate of reaction. It has been determined that this reaction occurs from 30 to 300 times more rapidly within the membrane, while even higher values have been suggested for proteins. The autoxidation of ,NO in membranes is not the main route for cellular ,NO consumption but an important consequence of this phenomenon is to focus the generation of significant amounts of oxidizing and nitrosating molecules (nitrogen dioxide and dinitrogen trioxide) in the small volume comprised by cellular membranes. Even so, these reactive species are diffusible and their ultimate fate will depend on the reactivity towards available substrates rather than on physical barriers. The acceleration of ,NO autoxidation by biological hydrophobic phases may thus be a general phenomenon that increases in importance in cases of ,NO overproduction. IUBMB Life, 59: 243-248, 2007 [source] Bioprocesses for the removal of nitrogen oxides from polluted airJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2005Yaomin Jin Abstract Nitrogen oxides (NOx) of environmental concern are nitrogen monoxide (NO) and nitrogen dioxide (NO2). They are hazardous air pollutants that lead to the formation of acid rain and tropospheric ozone. Both pollutants are usually present simultaneously and are, therefore, called NOx. Another compound is N2O which is found in the stratosphere where it plays a role in the greenhouse effect. Concern for environmental and health issues coupled with stringent NOx emission standards generates a need for the development of efficient low-cost NOx abatement technologies. Under such circumstances, it becomes mandatory for each NOx-emitting industry or facility to opt for proper NOx control measures. Several techniques are available to control NOx emissions: selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), adsorption, scrubbing, and biological methods. Each process offers specific advantages and limitations. Since bioprocesses present many advantages over conventional technologies for flue gas cleaning, a lot of interest has recently been shown for these processes. This article reviews the major characteristics of conventional non-biological technologies and recent advances in the biological removal of NOx from flue gases based on the catalytic activity of either eucaryotes or procaryotes, ie nitrification, denitrification, the use of microalgae, and a combined physicochemical and biological process (BioDeNOx). Relatively uncomplicated design and simple operation and maintenance requirements make biological removal a good option for the control of NOx emissions in stationary sources. Copyright © 2005 Society of Chemical Industry [source] Air pollution and hospitalization for venous thromboembolic disease in ChileJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 4 2010R. E. DALES See also Mannucci PM. Fine particulate: it matters. This issue, pp 659,61; Bonzini M, Tripodi A, Artoni A, Tarantini L, Marinelli B, Bertazzi PA, Apostoli P, Baccarelli A. Effects of inhalable particulate matter on blood coagulation. This issue, pp 662,8. Summary.,Background:,Ambient air pollution is a risk factor for stroke and myocardial infarction, possibly because of alterations in coagulation that influence the arterial circulation. Whether air pollution influences diseases associated with peripheral venous thrombogenesis remains largely unknown. Objectives: To determine the association between air pollution and venous thromboembolic disease (VTE) in a sample of the general population. Methods: A time-series analysis was used to test the association between daily air pollution and VTE hospitalizations in Santiago between 2001 and 2005. Results were adjusted for long-term trends, day of the week and average daily humidex. Results: From a population of 5.4 million, there were, on average, 2.3 admissions for VTE per day. Pooled estimates of relative risk (RR) [95% confidence interval (CI)] of hospitalization for venous disease were: 1.07 (1.05, 1.09) for a 58.4 p.p.b. increase in ozone (O3); 1.06 (1.02, 1.09) for a 5.85 p.p.b. increase in sulphur dioxide (SO2); 1.08 (1.03, 1.12) for a 29.25 ,g/m3 increase in nitrogen dioxide (NO2); and 1.05 (1.03, 1.06) for a 20.02 ,g/m3 increase in particulate matter , 2.5 ,m in mean aerodynamic diameter (PM2.5). For pulmonary embolism (PE) results were: 1.10 (1.07, 1.13) for O3; 1.05 (1.02, 1.08) for SO2; 1.07 (1.04, 1.09) for NO2; and 1.05(1.03, 1.06) for PM2.5, respectively. Conclusion: Air pollution appears to be a risk factor for venous thrombosis and PE, a disease with a significant fatality rate. [source] Ozone exposure and its influence on the worsening of childhood asthmaALLERGY, Issue 7 2009S. I. V. Sousa Background:, It is well documented that high levels of many airborne pollutants can adversely affect many systems of the human body. The aim of this study was to evaluate the specific impact of ozone (O3) on the worsening of childhood asthma, comparing children living at regions with high and low O3 concentrations (reference site) without the confounding effects of other pollutants. Methods:, Pollutant concentrations were monitored and data concerning asthma prevalence were collected through a questionnaire. The studied population consisted of 478 children aged 6,13 years old enrolled in four schools of the municipalities where monitoring was performed. Remote sites were identified with very low concentrations of nitrogen dioxide and volatile organic compounds and high concentrations of O3. Results:, The prevalence of wheeze for lifetime period and in the past year was 15.9% and 6.3%, respectively. Asthmatic children were identified when dyspnoea and wheezing were simultaneously mentioned in the absence of upper respiratory infections; according to that, the lifetime prevalence of asthmatic symptoms at the remote sites was 7.1%. The comparison with other previous studies was difficult because the criteria for analysis are not conveniently established. Conclusion:, The prevalence of childhood asthmatic symptoms was about 4% higher at the high O3 site than at the low O3 site. [source] Total serum IgE levels are associated with ambient ozone concentration in asthmatic adultsALLERGY, Issue 1 2009E. Rage Background:, Effects of air pollution exposure on IgE-mediated response in asthmatics are poorly investigated. The aim was to examine the relationship between air pollution concentrations and total IgE levels in adult asthmatics. Methods:, The present study relates to the 369 asthmatic adults from the French Epidemiological study on Genetics and Environment of Asthma (EGEA), with availability of data on both total serum IgE measurements and air pollution concentrations. Geo-statistical models were performed on 4 × 4 km grids to assess individual outdoor air pollution exposure. Annual outdoor concentrations of ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2), and particulate matter smaller than 10 ,m size (PM10), and concentrations of summer ozone were assigned to subject's home address. Results:, The geometric mean of total IgE was 161 IU/ml and the average of O3 exposure was 44.9 ± 9.5 ,g/m3. Ozone concentrations were positively related to total IgE levels and an increase of 10 ,g/m3 of O3 resulted in an increase of 20.4% (95% CI = 3.0,40.7) in total IgE levels. Adjustment for age, gender, smoking habits and previous life in the countryside did not change the results, and an increase of 19.1% (2.4,38.6) in total IgE was observed with O3. Negative associations observed between NO2 and total IgE levels disappeared after including O3 in the models. Neither SO2 nor PM10 were correlated with total IgE levels. Conclusions:, Results suggest that O3 or related ambient pollutants may up-regulate total IgE levels among asthmatic adults. [source] Delivery characteristics of a combined nitric oxide nasal continuous positive airway pressure systemPEDIATRIC ANESTHESIA, Issue 6 2002DEAA, R. Lindwall MD Summary Background: Nitric oxide (NO), when inhaled, has a synergistic effect with airway recruitment strategies such as positive endexpiratory pressure (PEEP) or continuous positive airway pressure (CPAP) in improving oxygenation in lung injury. Methods: We modified a commercially available nasal CPAP (nCPAP) system to enable the concomitant delivery of inhaled NO (iNO) and nCPAP to neonates and term babies. Oxygen, NO and nitrogen dioxide (NO2) concentrations were measured, comparing the effects of using 50 or 1000 parts per million (p.p.m.) NO stock gas cylinders. Results: Stable and accurate delivery of iNO was found for both stock gas concentrations. Using a 50 p.p.m. NO stock gas resulted in limited NO2 formation, with a maximum inspired NO2 concentration of , 0.3 p.p.m. (dose range up to 37 p.p.m. iNO), which was interpreted as the result of progressive dilution with nitrogen. In contrast, using a 1000 p.p.m. NO stock gas cylinder, inspired NO2 levels increased nonlinearly as expected with an increasing inspired concentration of NO. Conclusions: Inhaled NO can be safely and reliably delivered by the system we describe. The NO2 levels generated by the system are low, at least up to a dose of 37 p.p.m. NO, regardless of a stock gas concentration of 50 or 1000 p.p.m. NO. Using a 50 p.p.m. NO stock gas concentration, up to 80% oxygen can be given at 10 p.p.m. iNO. [source] Influence of NO2 molecule adsorption on free charge carriers and spin centers in porous siliconPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005E. A. Konstantinova Abstract The effect of nitrogen dioxide (NO2) adsorption on free charge carriers and spin centers in porous silicon has been studied by FTIR and ESR spectroscopy. The silicon dangling bond (Pb1 -center) density rises with increasing NO2 pressure (P) while free charge carrier concentration depends on P nonmonotonically. The experimental results are explained by a microscopic model taking into account both the formation of P,(NO2), donor,acceptor pairs and NO2 -induced oxidation of Si nanocrystal surfaces. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Oral cleft defects and maternal exposure to ambient air pollutants in New Jersey,BIRTH DEFECTS RESEARCH, Issue 4 2010Elizabeth G. Marshall BACKGROUND Evidence links exposure to ambient air pollution during pregnancy, particularly gaseous pollutants and particulate matter, to an increased risk of adverse reproductive outcomes though the results for birth defects have been inconsistent. METHODS We compared estimated exposure to ambient air pollutants during early pregnancy among mothers of children with oral cleft defects (cases) to that among mothers of controls, adjusting for available risk factors from birth certificates. We obtained ambient air pollutant data from air monitoring sites in New Jersey for carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), particulate matter <10 ,m in aerodynamic diameter (PM10) and particulate matter <2.5 ,m in aerodynamic diameter (PM2.5). We used values from the nearest monitor (within 40 km of the residence at birth) for controls, cleft lip with or without cleft palate (CLP) and cleft palate only (CPO). RESULTS Based on logistic regression analyses for each contaminant and all contaminants together, there were no consistent elevated associations between selected air pollutants and cleft malformations. Quartile of CO concentration showed a consistent protective association with CPO (p < 0.01). For other contaminants, confidence intervals (95%) of the odds ratios for some quartiles excluded one. CLP showed limited evidence of an association with increasing SO2 exposure while CPO showed weak associations with increasing O3 exposure. CONCLUSION There was little consistent evidence associating cleft malformations with maternal exposure to ambient air pollutants. Evaluating particular pollutants or disease subgroups would require more detailed measurement of exposure and classification of cleft defects. Birth Defects Research (Part A), 2010. © 2010 Wiley-Liss, Inc. [source] Hospital admissions for respiratory conditions in children and outdoor air pollution in Southwest Milan, ItalyACTA PAEDIATRICA, Issue 8 2010M Giovannini Abstract Aim:, To evaluate whether a relationship exists in hospital admissions for respiratory conditions in children with outdoor pollution in the Southwest Milan, Italy. Methods:, Daily count of hospital admissions for asthma, upper or lower respiratory diseases (LRD) occurred among children aged ,14 years at the San Paolo Hospital during 2007,2008 was recorded. Pollutants included the particular matter of <10 ,m diameter, ozone, carbon monoxide (CO) and nitrogen dioxide (NO2), reported on the same day of admission and 1 up to 5 days before admission. The moving weekly average (MWA) was also considered. Results:, Total respiratory admissions were associated with the same day level of CO (30.6% increase per 1 mg/m3 increase, 95% confidence interval, 3.9,69.9%) and with the MWA of NO2 (9.0% increase per 10 ,g/m3 increase, 1.2,16.8%). The effect of CO was stronger on upper respiratory diseases (URD) (lag 0, 21.3% increase, 6.4,38.3%). The effect of NO2 was stronger on LRD (MWA, 5.3% increase, 0.9,10.2%). Multipollutant models confirmed the role of CO on URD and that of NO2 on LRD. Conclusion:, Carbon monoxide and nitrogen dioxide may be associated with emergency hospital admissions for respiratory conditions among children in Southwest Milan. [source] Comparative Analysis of Indoor Levels of Suspended Particulates and Nitrogen Dioxide a Few Hours later after an Asthmatic AttackCHINESE JOURNAL OF CHEMISTRY, Issue 11 2007Emmanuel Ehiabhi UKPEBOR Abstract Suspended particulates (TSP) and nitrogen dioxide (NO2) are known respiratory irritants linked to asthma aggravation. This pilot study was designed to investigate the role of these pollutants on the frequency of asthmatic attack on two of the inhabitants of a household. The surveillance of TSP and NO2 in this household commenced a few hours later, after one of the occupants suffered an attack. The TSP load determination was done using a High Volume Gravimetric sampler and a light scattering method via a Haz-Dust 10 µm particulate monitor. Palmes Diffusion tubes for NO2 and a portable Crowcon Gasman toxic gas detector were utilized for NO2 screening. In the first day of monitoring in the living room, the in situ particulate sampler (Haz-Dust) recorded a mean TSP level of 26,000 µg·m,3. A confirmatory test with the eight hour average Gravimetric sampler gave 25,833 µg·m,3. With the use of the Gasman toxic gas detector for NO2, the NO2 concentration for the first few hours of sampling was lower than 188 µg·m,3, the detection limit of this instrument. However, the exact NO2 concentrations for the 7 day monitoring after the attack were 27.50 µg·m,3 (kitchen) and 12.03 µg·m,3 (living room) as recorded by the Palmes diffusion tubes. [source] Environmental risk factors and allergic bronchial asthmaCLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2005G. D'Amato Summary The prevalence of allergic respiratory diseases such as bronchial asthma has increased in recent years, especially in industrialized countries. A change in the genetic predisposition is an unlikely cause of the increase in allergic diseases because genetic changes in a population require several generations. Consequently, this increase may be explained by changes in environmental factors, including indoor and outdoor air pollution. Over the past two decades, there has been increasing interest in studies of air pollution and its effects on human health. Although the role played by outdoor pollutants in allergic sensitization of the airways has yet to be clarified, a body of evidence suggests that urbanization, with its high levels of vehicle emissions, and a westernized lifestyle are linked to the rising frequency of respiratory allergic diseases observed in most industrialized countries, and there is considerable evidence that asthmatic persons are at increased risk of developing asthma exacerbations with exposure to ozone, nitrogen dioxide, sulphur dioxide and inhalable particulate matter. However, it is not easy to evaluate the impact of air pollution on the timing of asthma exacerbations and on the prevalence of asthma in general. As concentrations of airborne allergens and air pollutants are frequently increased contemporaneously, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of allergic respiratory allergy and bronchial asthma. Pollinosis is frequently used to study the interrelationship between air pollution and respiratory allergy. Climatic factors (temperature, wind speed, humidity, thunderstorms, etc) can affect both components (biological and chemical) of this interaction. By attaching to the surface of pollen grains and of plant-derived particles of paucimicronic size, pollutants could modify not only the morphology of these antigen-carrying agents but also their allergenic potential. In addition, by inducing airway inflammation, which increases airway permeability, pollutants overcome the mucosal barrier and could be able to ,prime' allergen-induced responses. There are also observations that a thunderstorm occurring during pollen season can induce severe asthma attacks in pollinosis patients. After rupture by thunderstorm, pollen grains may release part of their cytoplasmic content, including inhalable, allergen-carrying paucimicronic particles. [source] | ||||||||||||||||