740 research outputs found
Organic molecular markers and signature from wood combustion particles in winter ambient aerosols: aerosol mass spectrometer (AMS) and high time-resolved GC-MS measurements in Augsburg, Germany
The impact of wood combustion on ambient aerosols was investigated in
Augsburg, Germany during a winter measurement campaign of a six-week period.
Special attention was paid to the high time resolution observations of wood
combustion with different mass spectrometric methods. Here we present and
compare the results from an Aerodyne aerosol mass spectrometer (AMS) and gas
chromatographic – mass spectrometric (GC-MS) analysed PM<sub>1</sub> filters on an
hourly basis. This includes source apportionment of the AMS derived organic
matter (OM) using positive matrix factorisation (PMF) and analysis of
levoglucosan as wood combustion marker, respectively.
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During the measurement period nitrate and OM mass are the main contributors
to the defined submicron particle mass of AMS and Aethalometer with 28%
and 35%, respectively. Wood combustion organic aerosol (WCOA) contributes
to OM with 23% on average and 27% in the evening and night time.
Conclusively, wood combustion has a strong influence on the organic matter
and overall aerosol composition. Levoglucosan accounts for 14% of WCOA
mass with a higher percentage in comparison to other studies. The ratio
between the mass of levoglucosan and organic carbon amounts to 0.06.
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This study is unique in that it provides a one-hour time resolution
comparison between the wood combustion results of the AMS and the GC-MS
analysed filter method at a PM<sub>1</sub> particle size range. The comparison of
the concentration variation with time of the PMF WCOA factor, levoglucosan
estimated by the AMS data and the levoglucosan measured by GC-MS is highly
correlated (<i>R</i><sup>2</sup> = 0.84), and a detailed discussion on the contributors
to the wood combustion marker ion at mass-to-charge ratio 60 is given. At
the end, both estimations, the WCOA factor and the levoglucosan
concentration estimated by AMS data, allow to observe the variation with
time of wood combustion emissions (gradient correlation with GC-MS
levoglucosan of <i>R</i><sup>2</sup> = 0.84). In the case of WCOA, it provides the
estimated magnitude of wood combustion emission. Quantitative estimation of
the levoglucosan concentration from the AMS data is problematic due to its
overestimation in comparison to the levoglucosan measured by the GC-MS
Mass and ionic composition of atmospheric fine particles over Belgium and their relation with gaseous air pollutants
Original article can be found at: http://www.rsc.org/publishing/journals/EM/Index.asp Copyright Royal Society of Chemistry. DOI: 10.1039/b805157gMass, major ionic components (MICs) of PM2.5, and related gaseous pollutants (SO2, NOx, NH3, HNO2, and HNO3) were monitored over six locations of different anthropogenic influence (industrial, urban, suburban, and rural) in Belgium. SO42-, NO3- NH4+, and Na+ were the primary ions of PM2.5 with averages diurnal concentrations ranging from 0.4-4.5, 0.3-7.6, 0.9-4.9, and 0.4-1.2 g/m3, respectively. MICs formed 39% of PM2.5 on an average, but it could reach up to 80-98 %. The SO2, NO, NO2, HNO2, and HNO3 levels showed high seasonal and site-specific fluctuations. The NH3 levels were similar over all the sites (2-6 g/m3), indicating its relation to the evenly distributed animal husbandry activities. The sulfur and nitrogen oxidation ratios for PM2.5 point towards a low-to-moderate formation of secondary sulfate and nitrate aerosols over five cities/towns, but their fairly intensive formation at the rural Wingene. Cluster analysis revealed the association of three groups of compounds in PM2.5; (i) NH4NO3, KNO3; (ii) Na2SO4; and (iii) MgCl2, CaCl2, MgF2, CaF2, corresponding to anthropogenic, sea-salt, and mixed (sea-salt + anthropogenic) aerosols, respectively. The neutralization and cation-to-anion ratios indicate that MICs of PM2.5 appeared mostly as (NH4)2SO4 and NH4NO3 salts. Sea-salt input was maximal during winter reaching up to 12 % of PM2.5. The overall average Cl-loss for sea-salt particles of PM2.5 at the six sites varied between 69 and 96 % with an average of 87 %. Principal component analysis revealed vehicular emission, coal/wood burning and animal farming as the dominating sources for the ionic components of PM2.5.Peer reviewe
Лечебно-диагностический алгоритм при очаговых тиреопатиях
Представлены современные данные о возможности развития тиреоидного рака на фоне доброкачественной патологии щитовидной железы, определены группы риска по развитию тиреоидных карцином. Разработан диагностический алгоритм своевременной и ранней диагностики рака щитовидной железы, предложены терапевтические подходы, направленные на предупреждение развития тиреоидного рака.Contemporary data about the possibility of thyroid carcinoma development against a background of thyroid pathology are presented. Risk groups of thyroid carcinoma development were determined. A diagnostic algorithm of timely and early diagnosis of thyroid carcinoma was worked out. Therapeutic approaches to prevention of thyroid cancer are suggested
Temporal and Geographical Contrasts in Pollutant Exposures – Implications for Epidemiological Research
Use of new measurement device to build a high-resolution network in Augsburg city – Smart Air Quality Network-Project
In traditional approach, the air quality in urban environment is monitored by relatively few measuring stations using stationary measuring technology. However, the spatial distribution of air pollutants in cities is very inhomogeneous and depends on various factors. The Smart Air Quality Network project (SAQN) is aimed to set up a dense network of sensor devices for particle mass and number concentration in the city of Augsburg (Germany) as well as conducting of intensive mobile measurements including walking and bike measurements. The main target is to generate real-time data that can be used for several actions and measures in order to reduce pollution levels as well as to inform people about the current levels of air pollutants. Furthermore, the data will be also used for the development and validation of dispersion and land use regression models.
For the purpose of this project, a novel measuring device is being developed by GRIMM Aerosol company, so-called “scientific scouts” (autonomous, mobile smart dust measurement devices that are auto-calibrated to a high-quality reference instrument within an intelligent monitoring network). In Phase 1 we already installed 15 scientific scouts at different sampling sites within the Augsburg city. The sampling sites are located in different environments: close to traffic and traffic hotspots, near combustion sources, in the city center and in urban background. In Phase II of this project 35 updated scientific scouts will be installed until summer 2019. The scientific scouts will be able to measure particle mass and number concentrations.
The preliminary results suggest good performance of the scientific scouts and their applicability for the purpose of SAQN project. Ongoing calibration will help to improve the performance and efficiency of the low-cost devices. On the other hand, the planned extension of the network in the following months will provide necessary data for the modelling approach
GIS-Based Estimation of Exposure to Particulate Matter and NO(2) in an Urban Area: Stochastic versus Dispersion Modeling
Stochastic modeling was used to predict nitrogen dioxide and fine particles [particles collected with an upper 50% cut point of 2.5 μm aerodynamic diameter (PM(2.5))] levels at 1,669 addresses of the participants of two ongoing birth cohort studies conducted in Munich, Germany. Alternatively, the Gaussian multisource dispersion model IMMIS(net/em) was used to estimate the annual mean values for NO(2) and total suspended particles (TSP) for the 40 measurement sites and for all study subjects. The aim of this study was to compare the measured NO(2) and PM(2.5) levels with the levels predicted by the two modeling approaches (for the 40 measurement sites) and to compare the results of the stochastic and dispersion modeling for all study infants (1,669 sites). NO(2) and PM(2.5) concentrations obtained by the stochastic models were in the same range as the measured concentrations, whereas the NO(2) and TSP levels estimated by dispersion modeling were higher than the measured values. However, the correlation between stochastic- and dispersion-modeled concentrations was strong for both pollutants: At the 40 measurement sites, for NO(2), r = 0.83, and for PM, r = 0.79; at the 1,669 cohort sites, for NO(2), r = 0.83 and for PM, r = 0.79. Both models yield similar results regarding exposure estimate of the study cohort to traffic-related air pollution, when classified into tertiles; that is, 70% of the study subjects were classified into the same category. In conclusion, despite different assumptions and procedures used for the stochastic and dispersion modeling, both models yield similar results regarding exposure estimation of the study cohort to traffic-related air pollutants
Association of lung function with declining ambient air pollution.
Recent studies have found a declining prevalence of respiratory infections in East German children, along with a tremendous improvement of air pollution since 1990. The present study evaluates the effects of improved air quality on lung function. Three consecutive cross-sectional surveys of schoolchildren ages 11-14 years from three communities in East Germany were performed in 1992-1993, 1995-1996, and 1998-1999. Lung function tests were available from 2,493 children. The annual mean of total suspended particulates (TSP) declined from 79 to 25 micro g/m(3), whereas levels for sulfur dioxide declined from 113 to 6 micro g/m(3). Mean forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV(1)) of the children increased from 1992-1993 to 1998-1999. The adjusted percent change of the geometric mean of FVC was 4.7% for a 50 micro g/m(3) decrease of TSP (p = 0.043) and 4.9% for a decrement of 100 micro g/m(3) SO(2) (p = 0.029). Effects on FEV(1) were smaller and not statistically significant. Our study indicates that a reduction of air pollution in a short time period may improve children's lung function
Influences of meteorological parameters and mixing layer height upon particle size distribution and VOC concentrations in urban areas
Ambient air temperature and temperature variability affecting blood pressure: a repeated-measures study in Augsburg, Germany
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