Publications (25)99.56 Total impact
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Article: Individual Day-Time Noise Exposure During Routine Activities and Heart Rate Variability in Adults: A Repeated Measures Study.
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ABSTRACT: BACKGROUND: Epidemiological studies have demonstrated associations between noise exposure and cardiovascular events. However, there have been few studies of possible underlying mechanisms. OBJECTIVES: We examined the association between individual day-time noise exposure and heart rate variability (HRV). METHODS: In a prospective panel study in Augsburg, Germany (March 2007-December 2008), 110 individuals participated in 326 electrocardiogram recordings with a mean duration of six hours. Five-minute averages of heart rate (HR) and HRV parameters were determined. Individual noise exposure was measured as A-weighted equivalent continuous sound pressure levels (Leq). Effects were estimated using additive mixed models adjusted for long- and short-term time trends and physical activity. Due to non-linear exposure-response functions we performed piecewise linear analyses with a cut-off point at 65 dB(A). RESULTS: Concurrent increases of 5dB(A) in Leq<65dB(A) were associated with increases in HR (%-change of mean value: 1.48%; 95% CI: 1.37, 1.60%) and the ratio of low frequency (LF) to high frequency (HF) power (4.89%; 95% CI: 3.48, 6.32%), and with decreases in LF (-3.77%; 95% CI: -5.49, -2.02%) and HF (-8.56%; 95% CI: -10.31, -6.78%) power. Standard deviation of normal-to-normal intervals (SDNN) was positively associated with concurrent noise <65dB(A) (5.74%; 95% CI: 5.13, 6.36) but negatively associated with noise lagged by five- to 15-minutes (-0.53% to -0.69%). Associations with cardiac function were less pronounced for noise ≥65dB(A), with some in opposite directions from associations with noise <65dB(A). Concurrent associations were modified by sex and age. CONCLUSIONS: Individual day-time noise exposure was associated with immediate changes in HRV, suggesting a possible mechanism linking noise to cardiovascular risk. Noise at lower levels may have health consequences beyond those resulting from "fight-or-flight" responses to high levels of noise.Environmental Health Perspectives 03/2013; · 7.04 Impact Factor -
Article: Selection of key ambient particulate variables for epidemiological studies - Applying cluster and heatmap analyses as tools for data reduction.
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ABSTRACT: The success of epidemiological studies depends on the use of appropriate exposure variables. The purpose of this study is to extract a relatively small selection of variables characterizing ambient particulate matter from a large measurement data set. The original data set comprised a total of 96 particulate matter variables that have been continuously measured since 2004 at an urban background aerosol monitoring site in the city of Augsburg, Germany. Many of the original variables were derived from measured particle size distribution (PSD) across the particle diameter range 3nm to 10μm, including size-segregated particle number concentration, particle length concentration, particle surface concentration and particle mass concentration. The data set was complemented by integral aerosol variables. These variables were measured by independent instruments, including black carbon, sulfate, particle active surface concentration and particle length concentration. It is obvious that such a large number of measured variables cannot be used in health effect analyses simultaneously. The aim of this study is a pre-screening and a selection of the key variables that will be used as input in forthcoming epidemiological studies. In this study, we present two methods of parameter selection and apply them to data from a two-year period from 2007 to 2008. We used the agglomerative hierarchical cluster method to find groups of similar variables. In total, we selected 15 key variables from 9 clusters which are recommended for epidemiological analyses. We also applied a two-dimensional visualization technique called "heatmap" analysis to the Spearman correlation matrix. 12 key variables were selected using this method. Moreover, the positive matrix factorization (PMF) method was applied to the PSD data to characterize the possible particle sources. Correlations between the variables and PMF factors were used to interpret the meaning of the cluster and the heatmap analyses.Science of The Total Environment 08/2012; 435-436:541-50. · 3.29 Impact Factor -
Article: Immediate ozone effects on heart rate and repolarisation parameters in potentially susceptible individuals.
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ABSTRACT: Elevated ozone levels have been associated with cardiovascular morbidity and mortality. We investigated the effects of ozone on heart rate (HR) and repolarisation parameters in potentially susceptible populations. Between March 2007 and December 2008, 363 ECG recordings including >2000 1 h intervals were measured in 64 individuals with type 2 diabetes or impaired glucose tolerance and in 46 healthy individuals with a potential genetic predisposition on the detoxification pathways from Augsburg, Germany. Associations between 1 h averages of ozone and HR, Bazett-corrected QT-interval (QTc), T-wave amplitude and T-wave complexity were analysed using additive mixed models. A variable indicating season and participants' location during the 1 h ECG recordings (summer and outdoors vs winter or indoors) was used as a potential ozone effect modifier. We observed concurrent and 1-4 h lagged increases in HR of 0.5-0.7% for each 20 μg/m(3) increase in ozone. These effects were stronger (1.0-1.2%) when participants were outdoors during the summer. We detected in all participants a concurrent (-1.31%; 95% CI -2.19% to -0.42%) and 1 h lagged (-1.32%; -2.19% to -0.45%) T-wave flattening. Elevated ozone levels were associated with 1 h (2.12%; 0.81 to 3.52) and 2 h lagged (1.89%; 0.55% to 3.26%) increases in T-wave complexity. However, no effects were seen for QTc. Ozone effects were generally more pronounced in individuals with metabolic disorders than a potential genetic predisposition. Changes in repolarisation might contribute to underlying pathophysiological changes associated with the link between elevated ozone levels and reported adverse cardiovascular outcomes.Occupational and environmental medicine 11/2011; 69(6):428-36. · 3.64 Impact Factor -
Article: The procoagulant effects of fine particulate matter in vivo.
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ABSTRACT: Inhalation of fine particulate matter (<2.5 μm; fine PM) has been shown to increase the risk for cardiovascular events. In this letter, we reappraise the role of tissue factor (TF) antigen and we also summarize changes in measured coagulation proteins in humans and rodents by other studies with fine PM. By considering all studies including ours, we conclude that monitoring the overall coagulation state by measuring capacity assays such as thrombin generation, and quantification of TF activity would be more suitable than determining single coagulation proteins (such as TF antigen) in order to better assess the systemic prothrombotic effects of fine PM.Particle and Fibre Toxicology 03/2011; 8:12; author reply 12. · 7.25 Impact Factor -
Article: Changes in deceleration capacity of heart rate and heart rate variability induced by ambient air pollution in individuals with coronary artery disease.
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ABSTRACT: Exposure to ambient particles has been shown to be responsible for cardiovascular effects, especially in elderly with cardiovascular disease. The study assessed the association between deceleration capacity (DC) as well as heart rate variability (HRV) and ambient particulate matter (PM) in patients with coronary artery disease (CAD). A prospective study with up to 12 repeated measurements was conducted in Erfurt, Germany, between October 2000 and April 2001 in 56 patients with physician-diagnosed ischemic heart disease, stable angina pectoris or prior myocardial infarction at an age of at least 50 years. Twenty-minute ECG recordings were obtained every two weeks and 24-hour ECG recordings every four weeks. Exposure to PM (size range from 10 nm to 2.5 μm), and elemental (EC) and organic (OC) carbon was measured. Additive mixed models were used to analyze the association between PM and ECG recordings. The short-term recordings showed decrements in the high-frequency component of HRV as well as in RMSSD (root-mean-square of successive differences of NN intervals) in association with increments in EC and OC 0-23 hours prior to the recordings. The long-term recordings revealed decreased RMSSD and pNN50 (% of adjacent NN intervals that differed more than 50 ms) in association with EC and OC 24-47 hours prior to the recordings. In addition, highly significant effects were found for DC which decreased in association with PM2.5, EC and OC concurrent with the ECG recordings as well as with a lag of up to 47 hours. The analysis showed significant effects of ambient particulate air pollution on DC and HRV parameters reflecting parasympathetic modulation of the heart in patients with CAD. An air pollution-related decrease in parasympathetic tone as well as impaired heart rate deceleration capacity may contribute to an increased risk for cardiac morbidity and sudden cardiac death in vulnerable populations.Particle and Fibre Toxicology 10/2010; 7:29. · 7.25 Impact Factor -
Article: Cardiovascular and inflammatory effects of intratracheally instilled ambient dust from Augsburg, Germany, in spontaneously hypertensive rats (SHRs).
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ABSTRACT: Several epidemiological studies associated exposure to increased levels of particulate matter in Augsburg, Germany with cardiovascular mortality and morbidity. To elucidate the mechanisms of cardiovascular impairments we investigated the cardiopulmonary responses in spontaneously hypertensive rats (SHR), a model for human cardiovascular diseases, following intratracheal instillation of dust samples from Augsburg. 250 μg, 500 μg and 1000 μg of fine ambient particles (aerodynamic diameter <2.5 μm, PM₂(.)₅-AB) collected from an urban background site in Augsburg during September and October 2006 (PM₂(.)₅ 18.2 μg/m³, 10,802 particles/cm3) were instilled in 12 months old SHRs to assess the inflammatory response in bronchoalveolar lavage fluid (BALF), blood, lung and heart tissues 1 and 3 days post instillation. Radio-telemetric analysis was performed to investigate the cardiovascular responses following instillation of particles at the highest dosage based on the inflammatory response observed. Exposure to 1000 μg of PM₂(.)₅-AB was associated with a delayed increase in delta mean blood pressure (ΔmBP) during 2(nd)-4(th) day after instillation (10.0 ± 4.0 vs. -3.9 ± 2.6 mmHg) and reduced heart rate (HR) on the 3rd day post instillation (325.1 ± 8.8 vs. 348.9 ± 12.5 bpm). BALF cell differential and inflammatory markers (osteopontin, interleukin-6, C-reactive protein, and macrophage inflammatory protein-2) from pulmonary and systemic level were significantly induced, mostly in a dose-dependent way. Protein analysis of various markers indicate that PM₂(.)₅-AB instillation results in an activation of endothelin system (endothelin1), renin-angiotensin system (angiotensin converting enzyme) and also coagulation system (tissue factor, plasminogen activator inhibitor-1) in pulmonary and cardiac tissues during the same time period when alternation in ΔmBP and HR have been detected. Our data suggests that high concentrations of PM₂(.)₅-AB exposure triggers low grade PM mediated inflammatory effects in the lungs but disturbs vascular homeostasis in pulmonary tissues and on a systemic level by affecting the renin angiotensin system, the endothelin system and the coagulation cascade. These findings are indicative for promotion of endothelial dysfunction, atherosclerotic lesions, and thrombogeneis and, thus, provide plausible evidence that susceptible-predisposed individuals may develop acute cardiac events like myocardial infarction when repeatedly exposed to high pollution episodes as observed in epidemiological studies in Augsburg, Germany.Particle and Fibre Toxicology 09/2010; 7:27. · 7.25 Impact Factor -
Article: Changes in deceleration capacity of heart rate and heart rate variability induced by ambient air pollution in individuals with coronary artery disease
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ABSTRACT: Abstract Background and Objective Exposure to ambient particles has been shown to be responsible for cardiovascular effects, especially in elderly with cardiovascular disease. The study assessed the association between deceleration capacity (DC) as well as heart rate variability (HRV) and ambient particulate matter (PM) in patients with coronary artery disease (CAD). Methods A prospective study with up to 12 repeated measurements was conducted in Erfurt, Germany, between October 2000 and April 2001 in 56 patients with physician-diagnosed ischemic heart disease, stable angina pectoris or prior myocardial infarction at an age of at least 50 years. Twenty-minute ECG recordings were obtained every two weeks and 24-hour ECG recordings every four weeks. Exposure to PM (size range from 10 nm to 2.5 μm), and elemental (EC) and organic (OC) carbon was measured. Additive mixed models were used to analyze the association between PM and ECG recordings. Results The short-term recordings showed decrements in the high-frequency component of HRV as well as in RMSSD (root-mean-square of successive differences of NN intervals) in association with increments in EC and OC 0-23 hours prior to the recordings. The long-term recordings revealed decreased RMSSD and pNN50 (% of adjacent NN intervals that differed more than 50 ms) in association with EC and OC 24-47 hours prior to the recordings. In addition, highly significant effects were found for DC which decreased in association with PM2.5, EC and OC concurrent with the ECG recordings as well as with a lag of up to 47 hours. Conclusions The analysis showed significant effects of ambient particulate air pollution on DC and HRV parameters reflecting parasympathetic modulation of the heart in patients with CAD. An air pollution-related decrease in parasympathetic tone as well as impaired heart rate deceleration capacity may contribute to an increased risk for cardiac morbidity and sudden cardiac death in vulnerable populations.Particle and Fibre Toxicology. 01/2010; -
Article: Short-term effects of air pollution: a panel study of blood markers in patients with chronic pulmonary disease.
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ABSTRACT: Growing evidence indicates that ambient air pollution is associated with exacerbation of chronic diseases like chronic pulmonary disease. A prospective panel study was conducted to investigate short-term changes of blood markers of inflammation and coagulation in response to daily changes in air pollution in Erfurt, Germany. 12 clinical visits were scheduled and blood parameters were measured in 38 male patients with chronic pulmonary disease during winter 2001/2002. Additive mixed models with random patient intercept were applied, adjusting for trend, weekday, and meteorological parameters. Hourly data on ultrafine particles (UFP, 0.01-0.1 mum), accumulation mode particles (ACP, 0.1-1.0 mum), PM10 (particulate matter <10 mum in diameter), elemental (EC) and organic carbon (OC), gaseous pollutants (nitrogen monoxide [NO], nitrogen dioxide [NO2], carbon monoxide [CO], and sulphur dioxide [SO2]) were collected at a central monitoring site and meteorological data were received from an official network. For each person and visit the individual 24-hour average of pollutants immediately preceding the blood withdrawal (lag 0) up to day 5 (lag1-4) and 5-day running means were calculated. Increased levels of fibrinogen were observed for an increase in one interquartile range of UFP, PM10, EC, OC, CO, and NO revealing the strongest effect for lag 3. E-selectin increased in association with ACP and PM10 with a delay of one day. The ACP effect was also seen with the 5-day-mean. The pattern found for D-dimer was inconsistent. Prothrombin fragment 1+2 decreased with lag 4 consistently for all particulate pollutants. Von Willebrand factor antigen (vWF) showed a consistent decrease in association with almost all air pollutants with all lags except for lag 0. No associations were found for C-reactive protein, soluble intercellular adhesion molecule 1, serum amyloid A and factor VII. These results suggest that elevated concentrations of air pollution are associated with changes in some blood markers of inflammation and coagulation in patients with chronic pulmonary disease. The clinical implications of these findings need further investigation.Particle and Fibre Toxicology 09/2009; 6:25. · 7.25 Impact Factor -
Article: The influence of improved air quality on mortality risks in Erfurt, Germany.
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ABSTRACT: Around the world, daily variations in ambient air pollution have been consistently associated with variations in daily mortality. The aim of the study presented here was to assess the effects of ambient air pollution on daily mortality during a period of tremendous changes in air quality in the city of Erfurt, in eastern Germany, from October 1991 to March 2002. Data on particle size distributions were obtained from September 1995 to March 2002 at a research monitoring station. For particles from 0.01 microm to 2.5 microm in diameter, number concentrations (NCs)* and mass concentrations (MCs) were calculated. Particles with diameters less than or equal to 0.10 microm are defined as ultrafine particles (UFP). Data on the gaseous pollutants NO2, CO, SO2, and O3 and on PM10 (particulate matter [PM] with aerodynamic diameter less than or equal to 10 microm) were obtained from a government air-monitoring station. Data on changes in energy consumption, car fleet composition, and population were collected from local authorities. Death certificates of persons living in and dying in Erfurt were abstracted, and daily mortality counts were calculated. Poisson regression models were used to analyze the data, applying penalized splines (also known as P-splines) to model nonlinear relationships in the confounders. Model selection was done without air pollutants in the models, based on a combination of goodness-of-fit criteria and avoidance of autocorrelation in error terms. Final models included P-splines of time trend, meteorologic data, and influenza epidemics as well as day of the week with an indicator variable. Results are presented as change per interquartile range (IQR), i.e., change in the relative risk of mortality associated with a change in the concentration from the 25th to the 75th percentile of a given pollutant. Air pollutants were considered both as linear terms and as P-splines to assess the exposure-response functions. Changes in effect estimates over time were calculated using fully Bayesian time-varying coefficient models. This method was selected over four other approaches tested in simulation studies. Air-pollution concentrations decreased substantially in Erfurt during the decade under observation. The strongest changes were observed for SO2, for which annual concentrations decreased from 64 microg/m3 in 1992 to 4 microg/m3 in 2001. Concentrations of PM10, PM2.5 (particulate matter with aerodynamic diameter less than or equal to 2.5 microm), and CO decreased by more than 50%. NO2, O3, and ultrafine particles also decreased, though to a lesser extent. Based on visual inspection of the data on the changes in ambient air-pollution concentrations during the study period, we defined three study subperiods: A first subperiod from 1991 to 1995; a second, transitional subperiod from 1995 to 1998; and a third subperiod from 1998 to 2002. Generally, air-pollution concentrations decreased substantially from the first subperiod to the second, and some additional decreases occurred from the second subperiod to the third. During the second, transitional subperiod, natural gas replaced coal as the main energy source in Erfurt. In addition, the number of cars with catalytic converters increased over time, as did the number of cars in general. To facilitate the interpretation of the results, we organized the air pollutants into four groups: (1) NO2, CO, and ultrafine particles, (2) PM10 and PM2.5, (3) SO2, and (4) O3. We observed a 1.6% increased risk for daily mortality (CI, -0.4% to 3.5%) for an increase of 19.7 microg/m3 in NO2 (lag day 3), a 1.9% increased risk (CI, 0.2%-3.6%) for an increase of 0.48 mg/m3 in CO (lag day 4), and a 2.9% increased risk (CI, 0.3%-5.5%) for an increase of 9743/cm3 in ultrafine particles (lag day 4). No consistent associations were observed for PM10, PM2.5, or SO2. For O3, a 4.6% increased risk for daily mortality (CI, 1.1%-8.3%) was associated with a 43.8 microg/m3 maximum 8-hr concentration of O3 per day (lag day 2). For all four pollutants, exposure-response functions suggested no deviation from linearity. However, in time-varying models the strongest associations were observed for NO2, CO, and ultrafine particles during the transition subperiod, from 1995 to 1998, when O3 concentrations were lowest. Changes in source characteristics or ambient air-pollution concentrations were not able to explain these observations in a straightforward manner. However, the observations suggested that changes such as the introduction of three-way catalytic converters in cars and the substitution natural gas for coal might have been beneficial. Overall we concluded that: 1. Economic and political changes and the adoption of new technologies in eastern Germany resulted in distinct improvements in ambient air quality; 2. Urban air pollution in Erfurt changed within one decade from the eastern mixture toward that of western Europe ("western mixture"), which is dominated by concentrations of NOx, O3, fine particles, and ultrafine particles with low concentrations of SO2; 3. There was an association between daily mortality and ultrafine particles and combustion-related gases (lag days 3 or 4); 4. Ultrafine particles seemed to be the best pollution indicator and to point to the role of local combustion in the pollution mixture; 5. Regression coefficients showed variation over time for NO2, CO, ultrafine particles, and O3 that could not be explained by nonlinearity in the exposure-response functions; 6. Mortality associated with pollution was lower at the end of the 1990s than during the 1990s, except for mortality associated with O3; and 7. Mortality associated with pollution was strongest in the second, transitional subperiod, from 1995 to 1998, when changes in source characteristics had taken place but the benefits of improved ambient air quality had not yet been completely achieved.Research report (Health Effects Institute) 03/2009; -
Article: Short-term mortality rates during a decade of improved air quality in Erfurt, Germany.
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ABSTRACT: Numerous studies have shown associations between ambient air pollution and daily mortality. Our goal was to investigate the association of ambient air pollution and daily mortality in Erfurt, Germany, over a 10.5-year period after the German unification, when air quality improved. We obtained daily mortality counts and data on mass concentrations of particulate matter (PM)<10 microm in aerodynamic diameter (PM10), gaseous pollutants, and meteorology in Erfurt between October 1991 and March 2002. We obtained ultrafine particle number concentrations (UFP) and mass concentrations of PM<2.5 microm in aerodynamic diameter (PM2.5) from September 1995 to March 2002. We analyzed the data using semiparametric Poisson regression models adjusting for trend, seasonality, influenza epidemics, day of the week, and meteorology. We evaluated cumulative associations between air pollution and mortality using polynomial distributed lag (PDL) models and multiday moving averages of air pollutants. We evaluated changes in the associations over time in time-varying coefficient models. Air pollution concentrations decreased over the study period. Cumulative exposure to UFP was associated with increased mortality. An interquartile range (IQR) increase in the 15-day cumulative mean UFP of 7,649 cm(-3) was associated with a relative risk (RR) of 1.060 [95% confidence interval (CI), 1.008-1.114] for PDL models and an RR/IQR of 1.055 (95% CI, 1.011-1.101) for moving averages. RRs decreased from the mid-1990s to the late 1990s. Results indicate an elevated mortality risk from short-term exposure to UFP. They further suggest that RRs for short-term associations of air pollution decreased as pollution control measures were implemented in Eastern Germany.Environmental Health Perspectives 03/2009; 117(3):448-54. · 7.04 Impact Factor -
Article: Surgical smoke and ultrafine particles.
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ABSTRACT: Electrocautery, laser tissue ablation, and ultrasonic scalpel tissue dissection all generate a 'surgical smoke' containing ultrafine (<100 nm) and accumulation mode particles (< 1 mum). Epidemiological and toxicological studies have shown that exposure to particulate air pollution is associated with adverse cardiovascular and respiratory health effects. To measure the amount of generated particulates in 'surgical smoke' during different surgical procedures and to quantify the particle number concentration for operation room personnel a condensation particle counter (CPC, model 3007, TSI Inc.) was applied. Electro-cauterization and argon plasma tissue coagulation induced the production of very high number concentration (> 100000 cm-3) of particles in the diameter range of 10 nm to 1 mum. The peak concentration was confined to the immediate local surrounding of the production side. In the presence of a very efficient air conditioning system the increment and decrement of ultrafine particle occurrence was a matter of seconds, with accumulation of lower particle number concentrations in the operation room for only a few minutes. Our investigation showed a short term very high exposure to ultrafine particles for surgeons and close assisting operating personnel - alternating with longer periods of low exposure.Journal of Occupational Medicine and Toxicology 01/2009; 3:31. -
Article: Quality control and quality assurance for particle size distribution measurements at an urban monitoring station in Augsburg, Germany.
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ABSTRACT: Long-term observations of atmospheric constituents such as aerosol particles are increasingly needed to assess their impact on climate and human health. In contrast to particle mass concentration (MC), there are currently no standardized quality control (QC) and quality assurance (QA) procedures for the measurement of particle size distribution (PSD). This study describes some fundamental QC and QA procedures associated with the collection and evaluation of a 2 year dataset between 2005 and 2006 at an urban background monitoring site in Augsburg, Germany. The considered parametres include ambient PSD between 3 nm and 10 microm (merged from a twin differential mobility and an aerodynamic particle sizer, TDMPS and APS, respectively) as well as total particle number (TNC), length (LC) and MC determined by independent instruments. The hourly 1st and 0th moment of PSD showed good correlations with the independently measured LC (R(2) = 0.86) and TNC (R(2) = 0.79), respectively, the deviation for LC with 4% and for TNC with 22% being rather small. The volume concentration (3rd moment) of hourly measured PSD and the resultant MC (when assuming a realistic apparent density of 1.5 g cm(-3)) correlated well with the independently measured MC of PM(2.5) or PM(10) (R(2) > 0.86) and showed only small deviation from PM(2.5) (1%) or PM(10) (5%), respectively. The study demonstrates that the described QC and QA measures define both a high accuracy of the PSD measurements and their long-term comparability against data obtained in similar measurement programmes.Journal of Environmental Monitoring 09/2008; 10(9):1017-24. · 1.99 Impact Factor -
Article: Spatial and temporal variation of particle number concentration in Augsburg, Germany.
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ABSTRACT: Epidemiological studies on health effects of outdoor air pollution are largely based on a single monitoring site to estimate the exposure of people living in urban areas. For such an approach two aspects are important: the temporal correlation and the spatial variation of the absolute levels of concentrations measured at different sites in an urban area. Whereas many studies have shown small spatial variability of fine particles in urban areas, little is known on how well a single monitoring station could represent the temporal and spatial variation of ultrafine particles across urban areas. In our study we investigated the temporal and spatial variation of particle number concentration (PNC) at four background sites in Augsburg, Germany. Two of them were influenced by traffic, one was placed in the outskirts of the city. The average PNC levels at two urban background sites with traffic impact were 16,943 cm(-3) and 20,702 cm(-3), respectively, compared to 11,656 cm(-3) at the urban background site without traffic impact (ratio 1.5 to 1.8). The Spearman correlation coefficients between the monitoring sites were high (r>0.80). The pronounced differences in absolute PNC levels suggest that the use of a single monitoring station in long-term epidemiological studies must be insufficient to attribute accurate exposure levels of PNC to all study subjects. On the other hand, the high temporal correlations of PNC across the city area of Augsburg implicate that in epidemiological time-series studies the use of one single ambient monitoring site is an adequate approach for characterizing exposure to ultrafine particles.Science of The Total Environment 09/2008; 401(1-3):168-75. · 3.29 Impact Factor -
Article: Source apportionment of ambient fine particle size distribution using positive matrix factorization in Erfurt, Germany.
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ABSTRACT: Particle size distribution data collected between September 1997 and August 2001 in Erfurt, Germany were used to investigate the sources of ambient particulate matter by positive matrix factorization (PMF). A total of 29,313 hourly averaged particle size distribution measurements covering the size range of 0.01 to 3.0 microm were included in the analysis. The particle number concentrations (cm(-3)) for the 9 channels in the ultrafine range, and mass concentrations (ng m(-3)) for the 41 size bins in the accumulation mode and particle up to 3 microm in aerodynamic diameter were used in the PMF. The analysis was performed separately for each season. Additional analyses were performed including calculations of the correlations of factor contributions with gaseous pollutants (O(3), NO, NO(2), CO and SO(2)) and particle composition data (sulfate, organic carbon and elemental carbon), estimating the contributions of each factor to the total number and mass concentration, identifying the directional locations of the sources using the conditional probability function, and examining the diurnal patterns of factor scores. These results were used to assist in the interpretation of the factors. Five factors representing particles from airborne soil, ultrafine particles from local traffic, secondary aerosols from local fuel combustion, particles from remote traffic sources, and secondary aerosols from multiple sources were identified in all seasons.Science of The Total Environment 08/2008; 398(1-3):133-44. · 3.29 Impact Factor -
Article: Seasonal and diurnal variation of PM2.5 apparent particle density in urban air in Augsburg, Germany.
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ABSTRACT: The apparent particle density of particulate matter with aerodynamic diameter < 2.5 microm (rho2.5) was determined at an urban site in Augsburg, Germany and its correlation with chemical composition and meteorological conditions was investigated. rho2.5 showed strong day-to-day variation from 1.05 to 2.36 g cm(-3) (5 to 95% percentile), and nearly 64% of the daily variability could be explained by a multiple variable regression model. A minimum in the morning and afternoon (about 1.5 g cm(-3)), and a maximum (near 1.8 g cm(-3)) during midday was observed. The minima represent fresh primary aerosol emissions, which were related to traffic soot particles with low density due to their agglomerate structure, especially observed in the early morning hours of weekdays. The maximum is likely due to increased secondary particle production and the presence of more aged particles with the built-up of the convectively mixed boundary layer. rho2.5 has the potential to serve as a crude tracer for chemical composition and atmospheric processing and might play an important role when considering the associations between health effects and ambient particles.Environmental Science and Technology 08/2008; 42(14):5087-93. · 5.23 Impact Factor -
Article: Daily mortality and particulate matter in different size classes in Erfurt, Germany.
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ABSTRACT: The link between elevated concentrations of ambient particulate matter (PM) and increased mortality has been investigated in numerous studies. Here we analyzed the role of different particle size fractions with respect to total and cardio-respiratory mortality in Erfurt, Germany, between 1995 and 2001. Number concentrations (NC) of PM were measured using an aerosol spectrometer consisting of a Differential Mobility Particle Sizer and a Laser Aerosol Spectrometer to characterize particles between 0.01 and 0.5 and between 0.1 and 2.5 microm, respectively. We derived daily means of particle NC for ultrafine (0.01-0.1 microm) and for fine particles (0.01-2.5 microm). Assuming spherical particles of a constant density, we estimated the mass concentrations (MC) of particles in these size ranges. Concurrently, data on daily total and cardio-respiratory death counts were obtained from local health authorities. The data were analyzed using Poisson Generalized Additive Models adjusting for trend, seasonality, influenza epidemics, day of the week, and meteorology using smooth functions or indicator variables. We found statistically significant associations between elevated ultrafine particle (UFP; diameter: 0.01-0.1 microm) NC and total as well as cardio-respiratory mortality, each with a 4 days lag. The relative mortality risk (RR) for a 9748 cm(-3) increase in UFP NC was RR=1.029 and its 95% confidence interval (CI)=1.003-1.055 for total mortality. For cardio-respiratory mortality we found: RR=1.031, 95% CI: 1.003-1.060. No association between fine particle MC and mortality was found. This study shows that UFP, representing fresh combustion particles, may be an important component of urban air pollution associated with health effects.Journal of Exposure Science and Environmental Epidemiology 09/2007; 17(5):458-67. · 2.93 Impact Factor -
Article: Relationship between different size classes of particulate matter and meteorology in three European cities.
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ABSTRACT: Evidence on the correlation between particle mass and (ultrafine) particle number concentrations is limited. Winter- and spring-time measurements of urban background air pollution were performed in Amsterdam (The Netherlands), Erfurt (Germany) and Helsinki (Finland), within the framework of the EU funded ULTRA study. Daily average concentrations of ambient particulate matter with a 50% cut off of 2.5 microm (PM2.5), total particle number concentrations and particle number concentrations in different size classes were collected at fixed monitoring sites. The aim of this paper is to assess differences in particle concentrations in several size classes across cities, the correlation between different particle fractions and to assess the differential impact of meteorological factors on their concentrations. The medians of ultrafine particle number concentrations were similar across the three cities (range 15.1 x 10(3)-18.3 x 10(3) counts cm(-3)). Within the ultrafine particle fraction, the sub fraction (10-30 nm) made a higher contribution to particle number concentrations in Erfurt than in Helsinki and Amsterdam. Larger differences across the cities were found for PM2.5(range 11-17 microg m(-3)). PM2.5 and ultrafine particle concentrations were weakly (Amsterdam, Helsinki) to moderately (Erfurt) correlated. The inconsistent correlation for PM2.5 and ultrafine particle concentrations between the three cities was partly explained by the larger impact of more local sources from the city on ultrafine particle concentrations than on PM2.5, suggesting that the upwind or downwind location of the measuring site in regard to potential particle sources has to be considered. Also, relationship with wind direction and meteorological data differed, suggesting that particle number and particle mass are two separate indicators of airborne particulate matter. Both decreased with increasing wind speed, but ultrafine particle number counts consistently decreased with increasing relative humidity, whereas PM2.5 increased with increasing barometric pressure. Within the ultrafine particle mode, nucleation mode (10-30 nm) and Aitken mode (30-100 nm) had distinctly different relationships with accumulation mode particles and weather conditions. Since the composition of these particle fractions also differs, it is of interest to test in future epidemiological studies whether they have different health effects.Journal of Environmental Monitoring 05/2005; 7(4):302-10. · 1.99 Impact Factor -
Article: Metal-rich ambient particles (particulate matter 2.5) cause airway inflammation in healthy subjects.
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ABSTRACT: Epidemiologic studies have shown an increased prevalence of allergic asthma in children living in a German smelter area (Hettstedt) compared with a cohort who live in a nonindustrialized area (Zerbst). However, it is not known whether ambient particles (particulate matter(2.5) [PM(2.5)]) from these areas induce distinct lung inflammation, which might be an explanation for this difference. Therefore, 100 microg of PM(2.5) suspensions, collected simultaneously in the two areas, were instilled through a bronchoscope into contralateral lung segments of 12 healthy volunteers. PM(2.5) from both Hettstedt and Zerbst increased the number of leukocytes in the bronchoalveolar lavage performed 24 hours later. PM(2.5) from Hettstedt, but not Zerbst, induced a significant influx of monocytes (Hettstedt: 7.0% vs. Zerbst: 4.3%) without influencing the expression of surface activation markers on monocytes and alveolar macrophages. Oxidant radical generation of bronchoalveolar lavage cells and cytokine concentration (interleukin-6 and tumor necrosis factor-alpha) in bronchoalveolar lavage fluid was significantly increased after instillation of Hettstedt PM(2.5). We conclude that environmentally relevant concentrations of PM(2.5) from the smelter area induced distinct airway inflammation in healthy subjects with a selective influx of monocytes and increased generation of oxidant radicals. The higher concentration of transition metals in PM(2.5) from Hettstedt might be responsible for this increased inflammation.American Journal of Respiratory and Critical Care Medicine 11/2004; 170(8):898-903. · 11.08 Impact Factor -
Article: Relationship between indoor and outdoor levels of fine particle mass, particle number concentrations and black smoke under different ventilation conditions.
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ABSTRACT: Fine particle mass (PM(2.5)), black smoke (BS) and particle number concentration (NC) were measured simultaneously indoors and outdoors at an urban location in Erfurt, Germany. Measurements were conducted during 2-month periods in summer and winter. Different ventilation modes were applied during each measurement period: windows closed; windows opened widely for 15 min twice per day; windows and door across the room opened widely for 5 min twice per day and windows tilted open all day long. The lowest indoor/outdoor (I/O) ratios for all pollutants were found for closed windows, whereas the ratios for ventilated environments were higher. For closed windows, the I/O ratios for PM(2.5) are larger than the corresponding values for BS and NC (0.63 vs. 0.44 or 0.33, respectively) probably due to lower penetration factors for particles sizes <500 nm and higher deposition rates for ultrafine particles (<100 nm). The largest differences for the I/O ratios between closed and tilted windows were found for NC (0.33 vs. 0.78). The indoor and outdoor levels of PM(2.5) and BS were strongly correlated for all ventilation modes. The linear regression models showed that more than 75% of the daily indoor variation could be explained by the daily outdoor variation for those pollutants. However, the correlation between indoor and outdoor NC for ventilation twice a day was weak. It indicates that rapid changes of the air exchange rates during the day may affect the correlation and regression analysis of NC indoor and outdoor concentrations. This effect was not observed for PM(2.5) or BS. This study shows the importance of the indoor air aerosol measurements for health effects studies and the need for more research on I/O transport mechanisms for NC.Journal of Exposure Analysis and Environmental Epidemiology 07/2004; 14(4):275-83. · 2.72 Impact Factor -
Article: Variability of apparent particle density of an urban aerosol.
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ABSTRACT: The day to day and diurnal variation of apparent particle density was studied using highly time-resolved measurements of particle number distribution and fine-particle mass concentration. The study was conducted in Erfurt, Germany, from January 1, 1999, to November 22, 2000. A setup consisting of a differential mobility particle spectrometer and a laser aerosol spectrometer was used for particle number distribution measurements. PM2.5 particle mass was measured in parallel on an hourly basis using a tapered element oscillating microbalance (TEOM) and on daily base by using a Harvard marple impactor (HI). For the estimation of the mean apparent density of particles, number size distributions were converted into volume size distributions, assuming that the particles were spherically shaped. The volume size distributions were integrated over the range of 10 nm to 2.03 microm Stokes equivalent diameter to obtain volume concentrations. Mean apparent particle density was calculated as ratio of mass concentration and volume concentration. The mean apparent particle density, determined from HI and number size distribution on a daily basis was 1.6 +/- 0.5 g cm(-3). We found a strong day-to-day variation of apparent density ranging from 1.0 to 2.5 g cm(-3) (5th and 95th percentile). Furthermore, the apparent density showed pronounced diurnal pattern both in summer and in winter and also on weekdays and weekends. The apparent density was lowest in the morning and highest in the afternoon. The mean apparent density on an hourly basis was 1.4 +/- 0.5 and 1.5 +/- 0.5 g cm(-3) for PM2.5TEOM and corrected PM2.5TEOM using regression equation between daily mass concentration of HI and TEOM, respectively. The strong diurnal variation of apparent particle density was associated predominantly with the vertical temperature inversion and with traffic intensity. Thus, the apparent particle density depends on the physical particle properties and might be related to chemical composition of the sampled particle.Environmental Science and Technology 10/2003; 37(19):4336-42. · 5.23 Impact Factor
Top co-authors
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Institutions
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2003–2013
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Ludwig-Maximilian-University of Munich
- Institute for Strategic Management
München, Bavaria, Germany
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2007–2012
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Universität Augsburg
Augsburg, Bavaria, Germany
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2009
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Helmholtz Zentrum München
- Institute of Epidemiology
München, Bavaria, Germany
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2008–2009
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Helmholtz-Zentrum für Umweltforschung
Leipzig, Saxony, Germany -
Hochschule, Ausburg
Augsburg, Bavaria, Germany
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