Air pollution remains a significant issue, particularly in urban areas. This study explored the prediction of hourly point-based PM10 concentrations using the XGBoost algorithm to assimilate them ...into a geostatistical land use regression model for spatially and temporally high-resolution prediction maps. The model configuration and training incorporated meteorological data, station metadata, and time variables based on statistical values and expert knowledge. Hourly measurements from approximately 400 stations from 2009 to 2017 were used for training. The selected model performed with a mean absolute error (MAE) of 6.88 μg m−3, root mean squared error (RMSE) of 9.95 μg m−3, and an R² of 0.65, with variations depending on the siting type and surrounding area. The model achieved a high accuracy of 98.54% and a precision of 73.96% in predicting exceedances of the current EU-limit value for the daily mean of 50 μg m−3. Despite identified limitations, the model can effectively predict hourly values for assimilation into a geostatistical land use regression model.
Air pollution is a major health risk factor worldwide. Regular short- and long-time exposures to ambient particulate matter (PM) promote various diseases and can lead to premature death. Therefore, ...in Germany, air quality is assessed continuously at approximately 400 measurement sites. However, knowledge about this intermediate distribution is either unknown or lacks a high spatial–temporal resolution to accurately determine exposure since commonly used chemical transport models are resource intensive. In this study, we present a method that can provide information about the ambient PM concentration for all of Germany at high spatial (100 m × 100 m) and hourly resolutions based on freely available data. To do so we adopted and optimised a method that combined land use regression modelling with a geostatistical interpolation technique using ordinary kriging. The land use regression model was set up based on CORINE (Coordination of Information on the Environment) land cover data and the Germany National Emission Inventory. To test the model’s performance under different conditions, four distinct data sets were used. (1) From a total of 8760 (365 × 24) available h, 1500 were randomly selected. From those, the hourly mean concentrations at all stations (ca. 400) were used to run the model (n = 566,326). The leave-one-out cross-validation resulted in a mean absolute error (MAE) of 7.68μgm−3 and a root mean square error (RMSE) of 11.20μgm−3. (2) For a more detailed analysis of how the model performs when an above-average number of high values are modelled, we selected all hourly means from February 2011 (n = 256,606). In February, measured concentrations were much higher than in any other month, leading to a slightly higher MAE of 9.77μgm−3 and RMSE of 14.36μgm−3, respectively. (3) To enable better comparability with other studies, the annual mean concentration (n = 413) was modelled with a MAE of 4.82μgm−3 and a RMSE of 6.08μgm−3. (4) To verify the model’s capability of predicting the exceedance of the daily mean limit value, daily means were modelled for all days in February (n = 10,845). The exceedances of the daily mean limit value of 50 μgm−3 were predicted correctly in 88.67% of all cases. We show that modelling ambient PM concentrations can be performed at a high spatial–temporal resolution for large areas based on open data, land use regression modelling, and kriging, with overall convincing results. This approach offers new possibilities in the fields of exposure assessment, city planning, and governance since it allows more accurate views of ambient PM concentrations at the spatial–temporal resolution required for such assessments.
Research in the field of atmospheric science and epidemiology has long recognized the health effects of seasonal and meteorological conditions. However, little scientific knowledge exists to date ...about the impacts of atmospheric parameters on human mortality in tropical regions. Working within the scope of this systematic review, this investigation conducted a literature search using different databases; original research articles were chosen according to pre-defined inclusion and exclusion criteria. Both seasonal and meteorological effects were considered. The findings suggest that high amounts of rainfall and increasing temperatures cause a seasonal excess in infectious disease mortality and are therefore relevant in regions and populations in which such diseases are prevalent. On the contrary, moderately low and very high temperatures exercise an adverse effect on cardio-respiratory mortality and shape the mortality pattern in areas and sub-groups in which these diseases are dominant. Atmospheric effects were subject to population-specific factors such as age and socio-economic status and differed between urban and rural areas. The consequences of climate change as well as environmental, epidemiological and social change (e.g., emerging non-communicable diseases, ageing of the population, urbanization) suggest a growing relevance of heat-related excess mortality in tropical regions.
Air quality measurements usually consist of ground-based instrumentation at fixed locations. However, vertical profiles of pollutants are of interest for understanding processes, distribution, ...dilution and concentration. Therefore, a multicopter system has been developed to investigate the vertical distribution of the concentration of aerosol particles, black carbon, ozone, nitrogen oxides (NOx) and carbon monoxide and the meteorological parameters of temperature and humidity. This article presents the requirements by different users, the setup of the quadrocopter system, the instrumentation and the results of first applications. The vertical distribution of particulate matter next to a highway was strongly related to atmospheric stratification, with different concentrations below and above the temperature inversion present in the morning. After the qualification phase described in this article, two identically equipped multicopters will be used upwind and downwind of line or diffuse sources such as highways or urban areas to quantify the influence of their emissions on the local air quality.
The mean radiant temperature (Tmrt) is the most complex variable regarding the input parameters for heat balance models of human being that are the background for the assessment of thermally ...unfavourable conditions and heat stress. This paper investigates the simplification of past studies that the Tmrt is equal to the air temperature (Ta) under indoor conditions. In a second step, the causes for deviations between the two parameters are examined and integrated into the context of indoor climate. Measurements were conducted in four rooms at the Geography Department of Humboldt University in Berlin during autochthonal weather conditions from the 16th of August to the 2nd of September 2013. Tmrt was derived using integral radiation measurements and three different types of globe thermometers.
The study indicates that the deviations between the different methods of obtaining Tmrt are negligible for indoor environments. The results show that the differences between Ta and Tmrt are negligible during most periods, as stated in previous literature. As air temperatures increase, however, Tmrt exceeds Ta up to 1.3 K. The examination of the surface temperatures indicates that rooms with window walls facing southeast and southwest show the largest disparities between Ta and Tmrt. The correlation between Ta and Tmrt and the sum of the short and long wave radiation specifies the radiation intensity and duration as the main driver of Tmrt. Future studies on indoor heat stress should hence consider that Tmrt and Ta can differ depending on the characteristics of the room and on solar radiation.
•We examine differences between air temperature and mean radiant temperature.•Intensity and duration of incoming radiation are the main driver of the disparities.•Future studies regarding indoor heat stress are recommended to measure Tmrt.
Humans spend most of their time in confined spaces and are hence primarily exposed to the direct influence of indoor climate. The Universal Thermal Climate Index (UTCI) was obtained in 31 rooms ...(eight buildings) in Berlin, Germany, during summer 2013 and 2014. The indoor UTCI was determined from measurements of both air temperature and relative humidity and from data of mean radiant temperature and air velocity, which were either measured or modeled. The associated outdoor UTCI was obtained through facade measurements of air temperature and relative humidity, simulation of mean radiant temperature, and wind data from a central weather station. The results show that all rooms experienced heat stress according to UTCI levels, especially during heat waves. Indoor UTCI varied up to 6.6 K within the city and up to 7 K within building. Heat stress either during day or at night occurred on 35 % of all days. By comparing the day and night thermal loads, we identified maximum values above the 32 °C threshold for strong heat stress during the nighttime. Outdoor UTCI based on facade measurements provided no better explanation of indoor UTCI variability than the central weather station. In contrast, we found a stronger relationship of outdoor air temperature and indoor air temperature. Building characteristics, such as the floor level or window area, influenced indoor heat stress ambiguously. We conclude that indoor heat stress is a major hazard, and more effort toward understanding the causes and creating effective countermeasures is needed.
In-line particle size measurement with a spatial filter velocimetry probe for process control was already carried out successfully in conventional fluidized bed coating and agglomeration but has not ...yet been investigated in rotary fluidized bed agglomeration with a tangential spray for granulate and pellet manufacturing. In this project, a batch laboratory fluidized bed apparatus with a rotor insert and a tangential spray nozzle was used to investigate the feasibility of in-line particle size measurement with a spatial filter velocimetry probe and to detect critical process parameters.
First, particle size and particle size distribution of a placebo mixture including small and large pellets were measured directly with the in-line probe in the rotary fluidized bed without spraying and without agglomeration. The volume density distribution shows bimodal curves, the peaks of which are related to the different ratio of pellets. Second, microcrystalline cellulose powder was agglomerated with a binder solution in the rotary fluidized bed by tangential spraying. At-line dynamic image analysis for the particle size measurement was used for comparison and showed similar results to the spatial filter velocimetry method. A Plackett-Burman screening design identified spray rate, atomizing air pressure, rotor disk velocity and batch size as critical process parameters by measuring particle size, particle size distribution and sphericity. The spatial filter velocimetry probe can be used in rotary fluidized bed agglomeration with tangential spray for process control.
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•In rotary fluidized bed low amounts of large particles are clearly detected by SFV.•A strong correlation to Camsizer confirms suitability of SFV in rotary fluidized bed.•A low loading of the SFV probe ensures reliable measurements without coincidence.•Particle size and PSD increase with a high spray rate and a low atomizing air pressure.•Sphericity increases with a high rotor disk velocity.
The elemental carbon (EC)-tracer method was applied to PM10 and PM1 data of three sampling sites in the City of Berlin from February to October 2010. The sites were characterized by differing ...exposure to traffic and vegetation. The aim was to determine the secondary organic carbon (SOC) concentration and to describe the parameters influencing the application of the EC-tracer method. The evaluation was based on comparisons with results obtained from positive matrix factorization (PMF) applied to the same samples. To obtain site- and seasonal representative primary OC/EC-ratios (OC/ECp), the EC-tracer method was performed separately for each station, and additionally discrete for samples with high and low contribution of biomass burning. Estimated SOC-concentrations for all stations were between 11% and 33% of total OC. SOC-concentrations obtained with PMF exceeded EC-tracer results more than 100% at the park in the period with low biomass burning emissions in PM10. The deviations were besides others attributed to the high ratio of biogenic to combustion emissions and to direct exposure to vegetation. The occurrences of biomass burning emissions in contrast lead to increased SOC-concentrations compared to PMF in PM10. The obtained results distinguish that the EC-tracer-method provides well comparable results with PMF if sites are strongly influenced by one characteristic primary combustion source, but was found to be adversely influenced by direct and relatively high biogenic emissions.
A statistical design of experiments for a rotary fluidized bed agglomeration process is performed to improve both the knowledge of the process and the influence of the process parameters. ...Agglomerates of a pharmaceutical formulation are manufactured in a laboratory fluidized bed rotor apparatus with a tangential spray nozzle. Particle size is measured in-line over the entire agglomeration process with a spatial filter velocimetry probe installed directly in the process chamber and off-line with dynamic image analysis for comparison. The influence of the process parameters spray rate, spray pressure, rotor speed, and process air temperature on the fluidized bed is investigated using a central composite design. In-line measurement of particle size is possible over the entire rotor process. Spray pressure, spray rate, square of process air temperature, and some interactions proved to be statistically significant. Particle size measured with spatial filter velocimetry and dynamic image analysis indicates good agreement and a similar trend. The successful application of particle size measurement in a fluidized bed rotor agglomeration at a laboratory scale using spatial filter velocimetry to improve process control and reduce the risk of failed batches serves as the basis for transferring to a production scale.
Deposition of PM(10) particles to several types of urban surfaces was investigated within this study. Antimony was chosen as a tracer element to calculate dry deposition velocities for PM(10), since ...antimony proved to be present almost exclusively in PM(10) particles in ambient urban air. During 18 months, eight sampling sites in Berlin and Karlsruhe, two cities in Germany, were operated. PM(10) concentrations and dry deposition were routinely sampled as two week averages. Additionally, leaf-samples were collected at three sites with tall vegetation. The obtained deposition velocities ranged from 0.8 to 1.3 cms(-1) at roadside sites and from 0.4 to 0.5 cms(-1) at the other sites. With reference to the whole canopy, additional deposition velocities of about 0.5 cms(-1) were obtained for leaf surfaces. As a consequence, it can be concluded that vegetation-covered areas beside streets show the highest potential to capture particles in urban areas.
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