Search

Istanbul with its high urban population increase and rapid rate of its unplanned urbanization, it is critical to investigate the relations between urban heat island, population growth, and changes in the urban land use. The aim of this work is to study the local climate change and the effects of urbanization on urban climate of megacity Istanbul. Temporal variations of urban heat island (UHI) and UHI intensity in Istanbul were analyzed by using air temperature data measured by five meteorology stations for the period of 1951–2020. Minimum, maximum, and mean temperature data of Istanbul were used to understand the possible impacts of urbanization on the climate of the megacity. In addition, Corine Land Cover (CLC) datasets for the years 1990, 2000, 2012, and 2018, were used to visualize the spread of urban cover throughout the city. Seasonal observations data were statistically tested for monotonic trends. Significant upward trends in temperature were found in all selected stations, both rural and urban. The air temperature in urban areas, densely populated residential areas of the Istanbul, has increased more in years compared to its rural parts. The results showed an increase of night time (minimum temperature) temperature in both urban and rural stations between 0.010 – 0.047 °C yr-1 and an increase of daytime (maximum temperature) in all stations between 0.026 – 0.034 °C yr-1. The urban heat island impact increased over Istanbul with the expansion of the urban areas toward rural areas further reducing green areas.

In this study, we modeled the aerosol particle formation along air mass trajectories arriving at the remote Arctic research stations Gruvebadet (67 m a.s.l.) and Zeppelin (474 m a.s.l.), Ny-Ålesund, during May 2018. The aim of this study was to improve our understanding of processes governing secondary aerosol formation in remote Arctic marine environments. We run the Lagrangian chemistry transport model ADCHEM, along air mass trajectories generated with FLEXPART v10.4. The air masses arriving at Ny-Ålesund spent most of their time over the open ice-free ocean. In order to capture the secondary aerosol formation from the DMS emitted by phytoplankton from the ocean surface, we implemented a recently developed comprehensive DMS and halogen multi-phase oxidation chemistry scheme, coupled with the widely used Master Chemical Mechanism (MCM). The modeled median particle number size distributions are in close agreement with the observations in the marine-influenced boundary layer near-sea-surface Gruvebadet site. However, while the model reproduces the accumulation mode particle number concentrations at Zeppelin, it overestimates the Aitken mode particle number concentrations by a factor of ∼5.5. We attribute this to the deficiency of the model to capture the complex orographic effects on the boundary layer dynamics at Ny-Ålesund. However, the model reproduces the average vertical particle number concentration profiles within the boundary layer (0–600 m a.s.l.) above Gruvebadet, as measured with condensation particle counters (CPCs) on board an unmanned aircraft system (UAS). The model successfully reproduces the observed Hoppel minima, often seen in particle number size distributions at Ny-Ålesund. The model also supports the previous experimental findings that ion-mediated H2SO4–NH3 nucleation can explain the observed new particle formation in the marine Arctic boundary layer in the vicinity of Ny-Ålesund. Precursors resulting from gas- and aqueous-phase DMS chemistry contribute to the subsequent growth of the secondary aerosols. The growth of particles is primarily driven via H2SO4 condensation and formation of methane sulfonic acid (MSA) through the aqueous-phase ozonolysis of methane sulfinic acid (MSIA) in cloud and deliquescent droplets.

Government policies on renewing vehicle fleet by introducing newer, cleaner vehicles and removing old, polluting vehicles have significant impacts on air pollution. In this study, the estimated emissions of air pollutants that influence human health are reported together with health endpoints and corresponding mortality and morbidity costs under five alternative road transport policy scenarios, varying in scrapping rate and the shares of hybrid and electric vehicles. Using COPERT software, PM10, PM2.5, NO2, and SO2 emissions are determined for five scenarios. PM2.5 is the most reduced pollutant (41%) if the government adopts the most progressive scenario, followed by PM10 (27%) and NO2 (27%). A total of a maximum of 19,396 premature deaths and 803,328 years of life lost could be saved, corresponding to 252 billion TL cost savings over the 2020–2030 period if the most drastic policy encouraging an introduction of the newer and cleaner vehicles is adopted.

Urmia Lake (UL) located in the northwest of Iran, is one of the largest hypersaline lakes in the world. In recent years, most of the lake has been rendered to unusable lands. Drought and rapid increase in agricultural activities are the most important reasons behind the shrinkage of the lake. In this study, hydro-climatic data, Landsat satellite images and image processing techniques were used to detect the spatio-temporal land cover changes and salinization progress in Urmia Lake Basin (ULB) between 1975 and 2019. Increasing the area of irrigated lands from 1265 km2 in 1975 to 5525 km2 in 2011 in contrast to decreasing the water surface area of UL from 5982 km2 in 1995 to 586 km2 in 2014 and extension of salinization in the basin are the most important and thoughtful results of this study. Even the agricultural lands in the regions close to the lake have been affected by this environmental problem. The climatic conditions have gradually improved after 2014 and the government has released more water from dams to the lake. On the other hand, the area of irrigated lands has gradually decreased by 12% in the same period. As a result of these positive changes, the water surface area of the lake has gradually increased over 1000 km2. Based on the results of this study, both anthropogenic and climatic factors have played a positive role in UL restoration. Improvement of agricultural methods and providing a sustainable agricultural water management system under a changing climate can play the most effective role in the lake rehabilitation.

Major atmospheric oxidants (OH, O3 and NO3) dominate the atmospheric oxidation capacity, while H2SO4 is considered as a main driver for new particle formation. Although numerous studies have investigated the long-term trend of ozone in Europe, the trends of OH, NO3 and H2SO4 at specific sites are to a large extent unknown. The one-dimensional model SOSAA has been applied in several studies at the SMEAR II station and has been validated by measurements in several projects. Here, we applied the SOSAA model for the years 2007–2018 to simulate the atmospheric chemical components, especially the atmospheric oxidants OH and NO3, as well as H2SO4 at SMEAR II. The simulations were evaluated with observations from several shorter and longer campaigns at SMEAR II. Our results show that daily OH increased by 2.39% per year and NO3 decreased by 3.41% per year, with different trends of these oxidants during day and night. On the contrary, daytime sulfuric acid concentrations decreased by 2.78% per year, which correlated with the observed decreasing concentration of newly formed particles in the size range of 3–25 nm with 1.4% per year at SMEAR II during the years 1997–2012. Additionally, we compared our simulated OH, NO3 and H2SO4 concentrations with proxies, which are commonly applied in case a limited number of parameters are measured and no detailed model simulations are available., We applied the 1D model SOSAA to simulate the atmospheric concentrations of OH, NO3, and H2SO4 from 2007 to 2018 at SMEAR II. The results showed that daily OH increased by 2.39% per year and NO3 and H2SO4 decreased by 3.41% per year and 2.78% per year, respectively.

Major atmospheric oxidants (OH, O3 and NO3) dominate the atmospheric oxidation capacity, while H2SO4 is considered as a main driver for new particle formation events. Although numerous studies have investigated the long-term trend of ozone in Europe, the trend of OH, NO3 and H2SO4 at specific sites are to a large extent unknown. In this study, we investigated how the trends in major atmospheric oxidants (OH, O3 and NO3) and H2SO4 changed in southern Finland during the past 12 years and discuss how these trends relate to decreasing emissions of regulated air pollutants in Europe. The one-dimensional model SOSAA has been applied in several studies at the SMEAR II station, and has been validated by measurements in several projects. Here, we ran the SOSAA model for the years 2007–2018 to simulate the atmospheric chemical components, especially the atmospheric oxidants and H2SO4 at SMEAR II. The simulations were evaluated with observations at SMEAR II for several shorter and longer campaigns. Our results show that OH increased by +1.56 (−0.8; +3.17) % yr−1 during daytime and NO3 decreased by −3.92 (−6.49; −1.79) % yr−1 during nighttime, indicating different trends of the oxidants during day and night. Sulphuric acid decreased during daytime by −5.12 (−11.39; −0.52) % yr−1, which correlated with the observed decreasing concentration of newly formed particles in the size range 3–25 nm by 1.4 % yr−1 at SMEAR II during the years 1997–2012 (Nieminen et al., 2014). Additionally we compared our simulated OH, NO3 and H2SO4 concentrations with proxies, which are commonly applied in case limited amount of parameters are measured and no detailed model simulations are available.

Residential heating is one of the major sectors that contribute to emissions of harmful air pollutants in urban areas. In Istanbul, local sources are the main contributors of particulate matter levels. To quantify the contributions of residential heating sector to ambient particulate matter concentrations, we have developed an up to date spatially distributed high-resolution emissions inventory based on local activity data. The air quality simulations were conducted using the CMAQ (version 5.2). Our study results showed that our high-resolution emissions of the residential heating sector significantly improve the spatial distribution and concentration of air pollutants (SO 2, PM 10, PM 2.5) for Istanbul. Air quality model simulations with our high-resolution emissions underestimated PM 10 concentrations throughout the study episode on average by only 4.16% with a mean bias of 2.23 μg/m −3 while base inventory underestimated PM 10 concentrations on average by 35.1% with a mean bias of 18.91 μg/m −3. Results show that our spatially distributed high-resolution emissions inventory produces more realistic results for Istanbul during wintertime when residential heating has the most influence on local air pollution.

Urmia Lake located in the north-west of Iran, is one of the largest hyper-saline lakes in the world. In recent years, most of the Urmia Lake have been rendered to unusable lands. Drought and rapid increase in agricultural activities are the most important reasons behind the shrinkage of the Lake. This kind of exploitation with the added salinity from irrigation occurring over time has caused increased soil salinity in the basin leading up to desertification. Soil salinity research are crucial to understand underlying causes and consequences of the drying Urmia Lake. In this study, we use remote sensing technology and image processing techniques to detect spatio-temporal variability of salt body, salt affected lands, and development of irrigated lands to estimate the extend of salinization in terms of spectral response of satellite images for the Urmia Lake Basin from 1975 to 2016. The results of this study indicate that salt and salty soil areas has increased dramatically from 1995 to 2014 and more than 5000 km2 of Urmia Lake's water surface area was converted to salt or salty soil bodies during recent years. Salinization and desertification progress are not limited to just dried bottom of the Urmia Lake. Although the area of irrigated lands has increased more than two times during the studied period, soil salinity has increased in regions close to Urmia Lake too. This desertification in the basin have potential to be the source of dust storms, which have adverse effects on people's life and climate as well.