ÖMER AĞA
• Dr Ömer AĞA has been working as associate Professor in environmental engineering at Department of Environmental Engineering, Faith University, Istanbul, Turkey since 2001. He received his Ph.D. in environmental engineering from Middle East technical University, Turkey in 2000. Ömer AĞA has become visiting professor to the Department of Environmental Engineering, University of Dammam, KSA since 2009.
• Dr Ömer AĞA's work is focused on Environmental Impact Assessment (EIA), hazardous waste management, water treatment, solid waste management, Soil pollution and remediation, Air quality and pollution control. He has been involved in more than 30 consultancy works and industrial testing for industries in the field of solid waste management, air quality, industrial wastewater treatment, and EIA etc. He has conducted over 15 national funded research projects.
• Dr AĞA has published to date over 40 refereed articles in professional journals/proceedings, 1 chapters in refereed international level books and 1 chapters in refereed national level books. Dr AĞA continues to serve as peer reviewer for several international journals (including, Environment international, Soil, Air and water Pollution, Atmospheric research, Environmental Engineering Sciences, etc…).He has granted various research awards related to air, water and soil pollution management. He is participated in many Scientifics research
Supervisors: Prof Gurdal TUNCEL
• Dr Ömer AĞA's work is focused on Environmental Impact Assessment (EIA), hazardous waste management, water treatment, solid waste management, Soil pollution and remediation, Air quality and pollution control. He has been involved in more than 30 consultancy works and industrial testing for industries in the field of solid waste management, air quality, industrial wastewater treatment, and EIA etc. He has conducted over 15 national funded research projects.
• Dr AĞA has published to date over 40 refereed articles in professional journals/proceedings, 1 chapters in refereed international level books and 1 chapters in refereed national level books. Dr AĞA continues to serve as peer reviewer for several international journals (including, Environment international, Soil, Air and water Pollution, Atmospheric research, Environmental Engineering Sciences, etc…).He has granted various research awards related to air, water and soil pollution management. He is participated in many Scientifics research
Supervisors: Prof Gurdal TUNCEL
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were collected at two sampling sites near
Büyükçekmece Lake, one of the important drinking
water sources of Istanbul, for the period of
October 2001 to July 2002. The study comprised
the determination of trace and toxic metals concentrations
in rain water. The concentrations of
the metals in this study were found to be higher
than those reported by other researchers around
the world. The solubility of toxic metals was found
in the order of Cd > Cu > V > Zn > Ni > Pb
> Cr. Solubility of metals under acidic conditions
(pH < 5.5) was approximately five times higher
than those under neutral conditions with Cd as
the most soluble metal (50% soluble). Statistical
evaluations including seasonal variations, crustal
enrichment factors, and correlation matrix were
discussed to identify the possible sources of these
pollutants. The study revealed that anthropogenic
elements were highly enriched especially for Cd
> Cu > Pb which were found to be highly enriched.
Significant portion of Cu and Pb could
be increased by the effect of local sources like
cement industry in the area; however, the rest of
drinking water sources of Istanbul city, was studied during October 2001–July 2002. Seventy-nine
bulk precipitation samples were collected at two sampling stations near the Lake (4182V35WN,
28835V25WE and 4185V30WN, 28837V7WE). The study comprised the determination of H+, Cl, NO3
,
SO4
2, NH4
+, Na, K, Mg, Ca, Al, Ba, Fe, Cu and Mn concentrations in bulk deposition rain event
samples. The average volume-weighted pH value was found to be 4.81, which points out that the rain
is slightly acidic. High sulfate concentrations were observed together with high H+ ion values. Sulfur
emissions were the major cause for the observed high hydrogen ion levels. On the basis of factor
analysis and correlation matrix analysis, it has been found that in this region, acid neutralization is
brought about by calcium rather than the ammonium ion. The varimax rotated factor analysis
grouped the variables into four factors, which are crustal, marine and two anthropogenic sources.
and Bursa aerosols were investigated to assess size distributions, spatial and temporal variability,
sources and source regions affecting the composition of aerosols in Uluda˘g and Bursa. A total of 81
samples were collected in two sites, one in Bursa city and another in the Uluda˘g Mountain during
two sampling campaigns. Daily samples were collected using a high volume sampler on Whatman
41 cellulose filters in Uluda˘g, while three days interval samples were collected in Bursa using an
automatic dichotomous sampler on PTFE Teflon filters. Samples were analysed for 15 trace and
heavy metals (Al, Fe, Ba, Na, Mg, K, Mn, Ca, Cu), (V, Pb, Cd, Cr, Ni, Zn), and 4 major ions (SO2−
4 ,
NO−
3 , Cl−), (NH+
4 ) using ICP-AES, GFAAS, HPLC and UV/VIS Spectrophotometer, respectively.
In general, concentrations of the metals measured in Uluda˘g aerosols were lower than those in Bursa.
The concentrations of crustal elements were higher in summer than winter, while anthropogenic
elements had higher concentrations in winter than summer. Most of the mass of crustal elements
was concentrated in the coarse mode while the mass of the heavy metals was concentrated in the fine
mode. Factor analysis revealed four factors with sources including crustal, industrial and combustion.
Back trajectory calculations were used to determine long range contributions. These calculations
showed that contributions were mostly from European countries, former Soviet Union countries,
Black Sea and North Africa.
hand, information about fine fraction aerosols (PM2.5) in Istanbul atmosphere was not reported. In this study, 86 daily
aerosol samples were collected between July2002 and July 2003. The PM10 annual arithmetic mean value of
47.1 lg m3, was lower than the Turkish air qualitystandard of 60 lg m3. On the other hand, this value was found
higher than the annual European Union air qualityPM 10 standard of 40 lg m3. Furthermore, the annual mean concentration
of PM2.5 20.8 lg m3 was found higher than The United States EPA standard of 15 lg m3. The statistics
and relationships of fine, coarse, and inhalable particles were studied. Cyclic behavior of the monthly average concentrations
of PM10 and PM2.5 data were investigated. Several frequencydistribution functions were used to fit the measured
data. According to Chi-squared and Kolmogorov–Smirnov tests, the frequencydistributions of PM2.5 and PM10
data were found to fit Log-logistic functions.
a better understanding of the elemental concentration and source contribution to both PM fractions. Sampling
location represents suburban part of Istanbul metropolitan city. Samples were collected on Teflon filters
using a “Dichotomous Sampler.” Concentrations of Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, and
Zn were measured by GFAAS, FAAS, and FAES techniques. Elemental variations of heating and nonheating
seasons were discussed. Fossil fuel-related atmospheric metals dramatically increased during the heating season,
while natural originated atmospheric metals increased during the nonheating season. Seasonal variations
of source contributions were evaluated using factor analysis, which was separately applied to the collected fine
and coarse particles data sets during heating and nonheating seasons (four data sets: PM2.5 heating, PM2.5 nonheating,
PM2.5–10 heating, and PM2.5–10 nonheating). Significant seasonal differences in source contributions
were observed. Four factor groups were extracted for PM2.5 dataset during the nonheating season, while five
factor groups were extracted for all the other cases. Mineral dust transportation, traffic, and industry-related
activities were classified as different factor groups in all the cases.
for soil treatment and stabilization.We evaluated the change in soil properties, and
the safety of lignin based stabilizer as a soil amendment. The environmental tests results
of the treated samples and leaching characteristics test were determined. These tests includes:
COD, BOD, P-PO4 3−, N-TKN, Sulfide, pH, Solubility, and Bio-assay test. The compaction
and California Bearing Ratio (CBR) characteristics of the resulting mixes were
evaluated. Soil samples were stabilized with various percentages of stabilizer concentrations.
As a result, the application of the soil stabilizer enhances the hydro-physical properties
of the soil as indicated by CBR tests and facilitates the immobilization of pollutants according
to environmental tests. It was found that this stabilizer is effective, environmentally
friendly and relatively cheap to be used for a variety of purposes. The results of the effects
and the suitability of the soil stabilizer are discussed in this paper
correlation between TOMS/Aerosol Index (AI) remote sensing particulate data
and Ground Level (GL) aerosol concentrations. GL fine and coarse particles
are collected from watershed area of Büyükçekmece at Marmara region in
Istanbul, Turkey (41°0.04′ N; 28°0.59′ E). Randomly collected, 24 hr GL
samples are statistically compared with the two years (2002–2003) TOMS/AI
data. It is found that there is a significant relationship (R2 = 0.47, p < 0.001)
between TOMS/AI data and wintertime GL aerosols. The relation of TOMS/AI
data and GL aerosol data are modelled using curvilinear models. Very good
agreements between the data sets are obtained. The obtained models are first
level exponential model and third level polynominal model for TOMS/AI
versus fine and TOMS/AI versus coarse data. R-square values of the models are
calculated as 0.92 and 0.67, respectively.
on the prevalence of respiratory diseases in children. The purpose
of this study was to examine the association between air pollution
and admissions for asthma and other respiratory diseases among
children who were younger than 15 yr of age. The study used data
on respiratory hospital admissions and air pollutant concentrations,
including thoracic particulate matter (PM10), fine (PM2.5),
and coarse (PM10-2.5) particulate matter in Zonguldak, Turkey. A
bidirectional case-crossover design was used to calculate odds
ratios for the admissions adjusted for daily meteorological parameters.
Significant increases were observed for hospital admissions
in children for asthma, allergic rhinitis (AR), and upper (UPRD)
and lower (LWRD) respiratory diseases. All fraction of PM in children
showed significant positive associations with asthma admissions.
The highest association noted was 18% rise in asthma
admissions correlated with a 10-mg/m3 increase in PM10-2.5 on the
same day of admissions. The adjusted odds ratios for exposure to
PM2.5 with an increment of 10 mg/m3 were 1.15 and 1.21 for asthma
and allergic rhinitis with asthma, respectively. PM10 exerted significant
effects on hospital admissions for all outcomes, including
asthma, AR, UPRD, and LWRD. Our study suggested a greater
effect of fine and coarse PM on asthma hospital admissions
compared with PM10 in children.
the most popular neural networks – the backpropagation algorithm, is proposed.
After the backpropagation training, the neural network, based on weather
forecasting data, determines the future concentration of critical air pollution
indicators. Depending on these concentrations, relevant episode warnings and
actions are activated. A case study is carried out to illustrate and validate
the method proposed, based on Istanbul air pollution data. Sulphur dioxide
and inhalable particulate matter are selected as air pollution indicators
(neural network outputs). Relevant episode measures are proposed. Among ten
backpropagation algorithms, the BFGS algorithm (Quasi-Newton algorithms) is
adopted since it showed the lowest training error. A comparison of NN-AirPol
method against regression and perceptron models showed significantly better
performance.
the atmosphere is investigated by analyzing 120 surface soil samples, collected from the urbanized area and its un-urbanized surrounding,
for major, minor and trace elements. Concentrations of elements from human activity (e.g. Cd, Pb, Cr, Zn, Cu and Ca) in the urbanized
area were higher than their corresponding concentrations in global average soil and soil in un-urbanized areas outside the urbanized area.
Metal contents in soil were very high in densely populated districts and around some industrial facilities. The only exception was Pb
distribution, which was more dispersed, due to the nature of motor vehicle emissions. Alteration of the Cd, Zn, Cu and Cr content of soil
was confined to the inhabited and industrial areas, whereas enrichment factors of these elements were close to unity in the remaining
study area. Factor analysis identified two polluted soil factor associations. One factor includes elements, such as Zn and Cd, which had
high factor scores in inhabited areas and the other factor (high loading of Pb) represents soil polluted by motor vehicle emissions.
bulk sintered superconductor, prepared from the commercially
available powder (Alfa-Aesar), have been investigated
before and after several γ irradiations up to 5000 MR. A minor
increase in the normal state resistance of the sample was
observed up to 5000 MR without any change in its critical
temperature (Tc). I–V characteristics before and after γ irradiation
with different doses up to 5000 MR were shown
and fitted to the expression V ∝ I β(T,B) where β approaches
unity near Tc before and after γ irradiation. A decrease in
the critical currents (Ic) with γ irradiation up to 1000 MR
was observed; after which they start to increase with higher
irradiations up to 5000 MR without exceeding the critical
currents before irradiation.
sediment samples were collected from 100 locations in Izmir Bay, five rivers and five sewer outfalls. The collected
samples were acid digested and analyzed by flame atomic absorption spectrometry FAAS., flame atomic emission
spectrometry FAES., graphite furnace atomic absorption spectrometry GFAAS. and X-ray fluorescence spectro-
metry XRF. for a total of 16 trace elements. Selected samples were also analyzed by instrumental neutron activation
analysis INAA. for 39 additional elements. The AAS, XRF and INAA techniques agreed fairly well for most of the
elements studied. The concentrations of elements showed significant differences between inner, middle and outer
bays with higher concentrations in the inner bay. The distributions of the crustal enrichment factors were also
prepared and investigated. Q 2000 Elsevier Science B.V. All rights reserved.
were collected at two sampling sites near
Büyükçekmece Lake, one of the important drinking
water sources of Istanbul, for the period of
October 2001 to July 2002. The study comprised
the determination of trace and toxic metals concentrations
in rain water. The concentrations of
the metals in this study were found to be higher
than those reported by other researchers around
the world. The solubility of toxic metals was found
in the order of Cd > Cu > V > Zn > Ni > Pb
> Cr. Solubility of metals under acidic conditions
(pH < 5.5) was approximately five times higher
than those under neutral conditions with Cd as
the most soluble metal (50% soluble). Statistical
evaluations including seasonal variations, crustal
enrichment factors, and correlation matrix were
discussed to identify the possible sources of these
pollutants. The study revealed that anthropogenic
elements were highly enriched especially for Cd
> Cu > Pb which were found to be highly enriched.
Significant portion of Cu and Pb could
be increased by the effect of local sources like
cement industry in the area; however, the rest of
drinking water sources of Istanbul city, was studied during October 2001–July 2002. Seventy-nine
bulk precipitation samples were collected at two sampling stations near the Lake (4182V35WN,
28835V25WE and 4185V30WN, 28837V7WE). The study comprised the determination of H+, Cl, NO3
,
SO4
2, NH4
+, Na, K, Mg, Ca, Al, Ba, Fe, Cu and Mn concentrations in bulk deposition rain event
samples. The average volume-weighted pH value was found to be 4.81, which points out that the rain
is slightly acidic. High sulfate concentrations were observed together with high H+ ion values. Sulfur
emissions were the major cause for the observed high hydrogen ion levels. On the basis of factor
analysis and correlation matrix analysis, it has been found that in this region, acid neutralization is
brought about by calcium rather than the ammonium ion. The varimax rotated factor analysis
grouped the variables into four factors, which are crustal, marine and two anthropogenic sources.
and Bursa aerosols were investigated to assess size distributions, spatial and temporal variability,
sources and source regions affecting the composition of aerosols in Uluda˘g and Bursa. A total of 81
samples were collected in two sites, one in Bursa city and another in the Uluda˘g Mountain during
two sampling campaigns. Daily samples were collected using a high volume sampler on Whatman
41 cellulose filters in Uluda˘g, while three days interval samples were collected in Bursa using an
automatic dichotomous sampler on PTFE Teflon filters. Samples were analysed for 15 trace and
heavy metals (Al, Fe, Ba, Na, Mg, K, Mn, Ca, Cu), (V, Pb, Cd, Cr, Ni, Zn), and 4 major ions (SO2−
4 ,
NO−
3 , Cl−), (NH+
4 ) using ICP-AES, GFAAS, HPLC and UV/VIS Spectrophotometer, respectively.
In general, concentrations of the metals measured in Uluda˘g aerosols were lower than those in Bursa.
The concentrations of crustal elements were higher in summer than winter, while anthropogenic
elements had higher concentrations in winter than summer. Most of the mass of crustal elements
was concentrated in the coarse mode while the mass of the heavy metals was concentrated in the fine
mode. Factor analysis revealed four factors with sources including crustal, industrial and combustion.
Back trajectory calculations were used to determine long range contributions. These calculations
showed that contributions were mostly from European countries, former Soviet Union countries,
Black Sea and North Africa.
hand, information about fine fraction aerosols (PM2.5) in Istanbul atmosphere was not reported. In this study, 86 daily
aerosol samples were collected between July2002 and July 2003. The PM10 annual arithmetic mean value of
47.1 lg m3, was lower than the Turkish air qualitystandard of 60 lg m3. On the other hand, this value was found
higher than the annual European Union air qualityPM 10 standard of 40 lg m3. Furthermore, the annual mean concentration
of PM2.5 20.8 lg m3 was found higher than The United States EPA standard of 15 lg m3. The statistics
and relationships of fine, coarse, and inhalable particles were studied. Cyclic behavior of the monthly average concentrations
of PM10 and PM2.5 data were investigated. Several frequencydistribution functions were used to fit the measured
data. According to Chi-squared and Kolmogorov–Smirnov tests, the frequencydistributions of PM2.5 and PM10
data were found to fit Log-logistic functions.
a better understanding of the elemental concentration and source contribution to both PM fractions. Sampling
location represents suburban part of Istanbul metropolitan city. Samples were collected on Teflon filters
using a “Dichotomous Sampler.” Concentrations of Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, and
Zn were measured by GFAAS, FAAS, and FAES techniques. Elemental variations of heating and nonheating
seasons were discussed. Fossil fuel-related atmospheric metals dramatically increased during the heating season,
while natural originated atmospheric metals increased during the nonheating season. Seasonal variations
of source contributions were evaluated using factor analysis, which was separately applied to the collected fine
and coarse particles data sets during heating and nonheating seasons (four data sets: PM2.5 heating, PM2.5 nonheating,
PM2.5–10 heating, and PM2.5–10 nonheating). Significant seasonal differences in source contributions
were observed. Four factor groups were extracted for PM2.5 dataset during the nonheating season, while five
factor groups were extracted for all the other cases. Mineral dust transportation, traffic, and industry-related
activities were classified as different factor groups in all the cases.
for soil treatment and stabilization.We evaluated the change in soil properties, and
the safety of lignin based stabilizer as a soil amendment. The environmental tests results
of the treated samples and leaching characteristics test were determined. These tests includes:
COD, BOD, P-PO4 3−, N-TKN, Sulfide, pH, Solubility, and Bio-assay test. The compaction
and California Bearing Ratio (CBR) characteristics of the resulting mixes were
evaluated. Soil samples were stabilized with various percentages of stabilizer concentrations.
As a result, the application of the soil stabilizer enhances the hydro-physical properties
of the soil as indicated by CBR tests and facilitates the immobilization of pollutants according
to environmental tests. It was found that this stabilizer is effective, environmentally
friendly and relatively cheap to be used for a variety of purposes. The results of the effects
and the suitability of the soil stabilizer are discussed in this paper
correlation between TOMS/Aerosol Index (AI) remote sensing particulate data
and Ground Level (GL) aerosol concentrations. GL fine and coarse particles
are collected from watershed area of Büyükçekmece at Marmara region in
Istanbul, Turkey (41°0.04′ N; 28°0.59′ E). Randomly collected, 24 hr GL
samples are statistically compared with the two years (2002–2003) TOMS/AI
data. It is found that there is a significant relationship (R2 = 0.47, p < 0.001)
between TOMS/AI data and wintertime GL aerosols. The relation of TOMS/AI
data and GL aerosol data are modelled using curvilinear models. Very good
agreements between the data sets are obtained. The obtained models are first
level exponential model and third level polynominal model for TOMS/AI
versus fine and TOMS/AI versus coarse data. R-square values of the models are
calculated as 0.92 and 0.67, respectively.
on the prevalence of respiratory diseases in children. The purpose
of this study was to examine the association between air pollution
and admissions for asthma and other respiratory diseases among
children who were younger than 15 yr of age. The study used data
on respiratory hospital admissions and air pollutant concentrations,
including thoracic particulate matter (PM10), fine (PM2.5),
and coarse (PM10-2.5) particulate matter in Zonguldak, Turkey. A
bidirectional case-crossover design was used to calculate odds
ratios for the admissions adjusted for daily meteorological parameters.
Significant increases were observed for hospital admissions
in children for asthma, allergic rhinitis (AR), and upper (UPRD)
and lower (LWRD) respiratory diseases. All fraction of PM in children
showed significant positive associations with asthma admissions.
The highest association noted was 18% rise in asthma
admissions correlated with a 10-mg/m3 increase in PM10-2.5 on the
same day of admissions. The adjusted odds ratios for exposure to
PM2.5 with an increment of 10 mg/m3 were 1.15 and 1.21 for asthma
and allergic rhinitis with asthma, respectively. PM10 exerted significant
effects on hospital admissions for all outcomes, including
asthma, AR, UPRD, and LWRD. Our study suggested a greater
effect of fine and coarse PM on asthma hospital admissions
compared with PM10 in children.
the most popular neural networks – the backpropagation algorithm, is proposed.
After the backpropagation training, the neural network, based on weather
forecasting data, determines the future concentration of critical air pollution
indicators. Depending on these concentrations, relevant episode warnings and
actions are activated. A case study is carried out to illustrate and validate
the method proposed, based on Istanbul air pollution data. Sulphur dioxide
and inhalable particulate matter are selected as air pollution indicators
(neural network outputs). Relevant episode measures are proposed. Among ten
backpropagation algorithms, the BFGS algorithm (Quasi-Newton algorithms) is
adopted since it showed the lowest training error. A comparison of NN-AirPol
method against regression and perceptron models showed significantly better
performance.
the atmosphere is investigated by analyzing 120 surface soil samples, collected from the urbanized area and its un-urbanized surrounding,
for major, minor and trace elements. Concentrations of elements from human activity (e.g. Cd, Pb, Cr, Zn, Cu and Ca) in the urbanized
area were higher than their corresponding concentrations in global average soil and soil in un-urbanized areas outside the urbanized area.
Metal contents in soil were very high in densely populated districts and around some industrial facilities. The only exception was Pb
distribution, which was more dispersed, due to the nature of motor vehicle emissions. Alteration of the Cd, Zn, Cu and Cr content of soil
was confined to the inhabited and industrial areas, whereas enrichment factors of these elements were close to unity in the remaining
study area. Factor analysis identified two polluted soil factor associations. One factor includes elements, such as Zn and Cd, which had
high factor scores in inhabited areas and the other factor (high loading of Pb) represents soil polluted by motor vehicle emissions.
bulk sintered superconductor, prepared from the commercially
available powder (Alfa-Aesar), have been investigated
before and after several γ irradiations up to 5000 MR. A minor
increase in the normal state resistance of the sample was
observed up to 5000 MR without any change in its critical
temperature (Tc). I–V characteristics before and after γ irradiation
with different doses up to 5000 MR were shown
and fitted to the expression V ∝ I β(T,B) where β approaches
unity near Tc before and after γ irradiation. A decrease in
the critical currents (Ic) with γ irradiation up to 1000 MR
was observed; after which they start to increase with higher
irradiations up to 5000 MR without exceeding the critical
currents before irradiation.
sediment samples were collected from 100 locations in Izmir Bay, five rivers and five sewer outfalls. The collected
samples were acid digested and analyzed by flame atomic absorption spectrometry FAAS., flame atomic emission
spectrometry FAES., graphite furnace atomic absorption spectrometry GFAAS. and X-ray fluorescence spectro-
metry XRF. for a total of 16 trace elements. Selected samples were also analyzed by instrumental neutron activation
analysis INAA. for 39 additional elements. The AAS, XRF and INAA techniques agreed fairly well for most of the
elements studied. The concentrations of elements showed significant differences between inner, middle and outer
bays with higher concentrations in the inner bay. The distributions of the crustal enrichment factors were also
prepared and investigated. Q 2000 Elsevier Science B.V. All rights reserved.