11 research outputs found
A Review of 21st-Century Studies
PM10 prediction has attracted special legislative and scientific attention due
to its harmful effects on human health. Statistical techniques have the
potential for high-accuracy PM10 prediction and accordingly, previous studies
on statistical methods for temporal, spatial and spatio-temporal prediction of
PM10 are reviewed and discussed in this paper. A review of previous studies
demonstrates that Support Vector Machines, Artificial Neural Networks and
hybrid techniques show promise for suitable temporal PM10 prediction. A review
of the spatial predictions of PM10 shows that the LUR (Land Use Regression)
approach has been successfully utilized for spatial prediction of PM10 in
urban areas. Of the six introduced approaches for spatio-temporal prediction
of PM10, only one approach is suitable for high-resolved prediction (Spatial
resolution < 100 m; Temporal resolution ¤ 24 h). In this approach, based upon
the LUR modeling method, short-term dynamic input variables are employed as
explanatory variables alongside typical non-dynamic input variables in a non-
linear modeling procedure
A Review on Different Modeling Techniques
In this study, the importance of air temperature from different aspects (e.g.,
human and plant health, ecological and environmental processes, urban
planning, and modelling) is presented in detail, and the major factors
affecting air temperature in urban areas are introduced. Given the importance
of air temperature, and the necessity of developing high-resolution spatio-
temporal air-temperature maps, this paper categorizes the existing approaches
for air temperature estimation into three categories (interpolation,
regression and simulation approaches) and reviews them. This paper focuses on
high-resolution air temperature mapping in urban areas, which is difficult due
to strong spatio-temporal variations. Different air temperature mapping
approaches have been applied to an urban area (Berlin, Germany) and the
results are presented and discussed. This review paper presents the
advantages, limitations and shortcomings of each approach in its original
form. In addition, the feasibility of utilizing each approach for air
temperature modelling in urban areas was investigated. Studies into the
elimination of the limitations and shortcomings of each approach are
presented, and the potential of developed techniques to address each
limitation is discussed. Based upon previous studies and developments, the
interpolation, regression and coupled simulation techniques show potential for
spatio-temporal modelling of air temperature in urban areas. However, some of
the shortcomings and limitations for development of high-resolution spatio-
temporal maps in urban areas have not been properly addressed yet. Hence, some
further studies into the elimination of remaining limitations, and improvement
of current approaches to high-resolution spatio-temporal mapping of air
temperature, are introduced as future research opportunities
The development of a dense urban air pollution monitoring network
The importance of air pollution monitoring networks in urban areas is well
known because of their miscellaneous applications. At the beginning of the
1990s, Berlin had more than 40 particulate matter monitoring stations,
whereas, by 2013, there were only 12 stations. In this study, a new and
free–of–charge methodology for the densifying of the PM10 monitoring network
of Berlin is presented. It endeavors to find the non–linear relationship
between the hourly PM10 concentration of the still–operating PM10 monitoring
stations and the shut–down stations by using the Artificial Neural Network
(ANN), and, consequently, the results of the shut–down stations were simulated
and re–constructed. However, input–variables selection is a pre–requisite for
any ANN simulation, and hence a new fuzzy–heuristic input selection has been
developed and joined to the ANN for the simulation. The hourly PM10
concentrations of the 20 shut–down stations were simulated and re–constructed.
The mean error, bias and absolute error of the simulations were 27.7%, –0.03
(μg/m3), and 7.4 (μg/m3), respectively. Then, the simulated hourly PM10
concentration data were converted to a daily scale and the performance of ANN
models which were developed for the simulation of the daily PM10 data were
evaluated (correlation coefficient >0.94). These appropriate results imply the
ability of the developed input selection technique to make the appropriate
selection of the input variables, and it can be introduced as a new input
variable selection for the ANN. In addition, a dense PM10 monitoring network
was developed by the combination of both the re–constructed (20 stations) and
the current (12 stations) stations. This dense monitoring network was applied
in order to determine a reliable mean annual PM10 concentration in the
different areas in Berlin in 2012
Evaluation of MARS for the spatial distribution modeling of carbon monoxide in an urban area
Spatial distribution modeling of CO in Tehran can lead to better air pollution
management and control, and it is also suitable for exposure assessment and
epidemiological studies. In this study MARS (Multi–variate Adaptive Regression
Splines) is compared with typical interpolation techniques for spatial
distribution modeling of hourly and daily CO concentrations in Tehran, Iran.
The measured CO data in 2008 by 16 monitoring stations were used in this
study. The Generalized Cross Validation (GCV) and Cross Validation techniques
were utilized for the parameter optimization in the MARS and other techniques,
respectively. Then the optimized techniques were compared based on the mean
absolute of percentage error (MAPE). Although the Cokriging technique
presented less MAPE than the Inverse Distance Weighting, Thin Plate Smooth
Splines and Kriging techniques, MARS exhibited the least MAPE. In addition,
the MARS modeling procedure is easy. Therefore, MARS has merit to be
introduced as an appropriate method for spatial distribution modeling. The
number of air pollution monitoring stations is very low (16 stations for 22
zones) and the distribution of stations is not suitable for spatial
estimation, hence the level of errors was relatively high (more than 60%).
Consequently, hourly and daily mapping of CO provides a limited picture of
spatial patterns of CO in Tehran, but it is suitable for estimation of
relative CO levels in different zones of Tehran. Hence, the map of mean annual
CO concentration was generated by averaging daily CO distributions in 2008. It
showed that the most polluted regions in Tehran are the central, eastern and
southeastern parts, and mean annual CO concentration in these parts (zones 6,
12, 13, 14 and 15) is between 4.2 and 4.6 ppm
Statistical Modeling Approaches for PM10 Prediction in Urban Areas; A Review of 21st-Century Studies
PM10 prediction has attracted special legislative and scientific attention due to its harmful effects on human health. Statistical techniques have the potential for high-accuracy PM10 prediction and accordingly, previous studies on statistical methods for temporal, spatial and spatio-temporal prediction of PM10 are reviewed and discussed in this paper. A review of previous studies demonstrates that Support Vector Machines, Artificial Neural Networks and hybrid techniques show promise for suitable temporal PM10 prediction. A review of the spatial predictions of PM10 shows that the LUR (Land Use Regression) approach has been successfully utilized for spatial prediction of PM10 in urban areas. Of the six introduced approaches for spatio-temporal prediction of PM10, only one approach is suitable for high-resolved prediction (Spatial resolution < 100 m; Temporal resolution ≤ 24 h). In this approach, based upon the LUR modeling method, short-term dynamic input variables are employed as explanatory variables alongside typical non-dynamic input variables in a non-linear modeling procedure
High-resolution air temperature mapping in urban areas: A review on different modelling techniques
In this study, the importance of air temperature from different aspects (e. g., human and plant health, ecological and environmental processes, urban planning, and modelling) is presented in detail, and the major factors affecting air temperature in urban areas are introduced. Given the importance of air temperature, and the necessity of developing high-resolution spatio-temporal air-temperature maps, this paper categorizes the existing approaches for air temperature estimation into three categories (interpolation, regression, and simulation approaches) and reviews them. This paper focuses on high-resolution air temperature mapping in urban areas, which is difficult due to strong spatio-temporal variations. Different air temperature mapping approaches have been applied to an urban area (Berlin, Germany) and the results are presented and discussed. This review paper presents the advantages, limitations, and shortcomings of each approach in its original form. In addition, the feasibility of utilizing each approach for air temperature modelling in urban areas was investigated. Studies into the elimination of the limitations and shortcomings of each approach are presented, and the potential of developed techniques to address each limitation is discussed. Based upon previous studies and developments, the interpolation, regression and coupled simulation techniques show potential for spatio-temporal modelling of air temperature in urban areas. However, some of the shortcomings and limitations for development of high-resolution spatio-temporal maps in urban areas have not been properly addressed yet. Hence, some further studies into the elimination of remaining limitations, and improvement of current approaches to high-resolution spatio-temporal mapping of air temperature, are introduced as future research opportunities
Groundwater Vulnerability Assessment to Pesticides and Their Ranking and Clustering
In this study, the different methods for groundwater vulnerability assessment to pesticides contamination and their uncertainties were introduced. Then, the groundwater vulnerability of agricultural regions of Pasha-Kolaa dam (Mazandaran province) to 7 pesticides has been assessed by the mobility potential indices in the typical conditions of pesticide properties (t1/2 and KOC) and the zonation maps of groundwater vulnerability in this region have been generated in the GIS environment. According to the uncertainty of the pesticide properties and the lack of necessary data for uncertainty analysis in the region of study, the mobility potential indices in different scenarios of pesticide properties (worst and best conditions of pesticide properties) (t1/2 and KOC) have been calculated, mapped and zoned. The zonation maps in three scenarios (best, typical and worst conditions of pesticide properties) were compared. Next, according to the regional values of mobility potential indices, generated for different scenarios, the pesticides are ranked using the composite programming method. Finally, the pesticides are clustered to three groups (suitable, transitional and unsuitable) by the combination of the results of previous sections. The clustering results showed that among of studied pesticides, 2,4 D Acid, Dimethoate and Fenvalerate are suitable ,and Metsulfuron and Triclopyr are unsuitable pesticides for region of study. The other pesticides showed transitional condition
A new structure identification scheme for ANFIS and its application for the simulation of virtual air pollution monitoring stations in urban areas
AbstractParameter and structure identifications are necessary in any modelling which aims to achieve a generalised model. Although ANFIS (Adaptive Network-based Fuzzy Inference System) employs well-known parameter-identification techniques, it needs to structure identification techniques for the determination of an optimum number of fuzzy rules and the selection of significant input variables from among the candidate input variables. In this study, a new structure identification scheme is developed and introduced, which is simultaneously capable of the selection of significant input variables and the determination of an optimum number of rules. This new structure identification was joined to ANFIS, and this joined modelling framework was applied to the simulation of virtual air-pollution monitoring stations in Berlin. In this study, 18 virtual particulate matter stations were simulated using the particulate matter data of some of the current stations. In other words, the particulate matter monitoring network of Berlin has been intensified. The evaluation of simulated virtual stations shows that, although the uncertainty of daily particulate matter measurement is about 10 percent, the simulated virtual stations can estimate the mean daily particulate matter with less than 10 percent of error. Mean absolute error and root mean square error of the simulations are less than 2.4 and 3.4µg/m3, respectively. The correlation coefficient of the simulation results was more than 0.94. In addition, the range of mean bias error is between −1.0 and 0.5µg/m3, and the range of factor of exceedance is between −14.8 and 10.8 percent. It means that the simulated virtual stations have a small bias. These results demonstrated the appropriate performance of the joined new structure identification scheme and ANFIS for development of a virtual air pollution monitoring network
A Comprehensive Statistical Study on Daytime Surface Urban Heat Island during Summer in Urban Areas, Case Study: Cairo and Its New Towns
Surface urban heat island (SUHI) is defined as the elevated land surface temperature (LST) in urban area in comparison with non-urban areas, and it can influence the energy consumption, comfort and health of urban residents. In this study, the existence of daytime SUHI, in Cairo and its new towns during the summer, is investigated using three different approaches; (1) utilization of pre-urbanization observations as LST references; (2) utilization of rural observations as LST references (urban–rural difference); and (3) utilization of the SIUHI (Surface Intra Urban Heat Island) approach. A time series of Landsat TM & ETM+ data (46 images) from 1984 to 2015 was employed in this study for daytime LST calculation during summer. Different statistical hypothesis tests were utilized for the evaluation of LST and SUHI in the case studies. The results demonstrated that there is no significant LST difference between the urban areas studied, and their corresponding built-up areas. In addition, daytime LST in new towns during the summer is 2 K warmer than in Cairo. Utilization of a pre-urbanization observations approach, alongside an evaluation of the long-term trend, demonstrated that there is no daytime SUHI during the summer in the study areas, and construction activities in the study areas do not result in cooling or warming effects. Utilization of the rural observations approach showed that LST is lower in Cairo than its surrounding areas. This demonstrates why the selection of suitable rural references in SUHI studies is an important and complicated task, and how this approach may lead to misinterpretation in desert city areas with significant landscape and surface difference with their most surrounding areas (e.g., Cairo). Results showed that, although SIUHI technique can be representative for the changes of variance of LST in urban areas, it is not able to identify the changes of mean LST in urban areas