An urban air quality assessment based on a meteorological perspective.

An integrated approach to understanding all measured pollutants with multi-discipline in different time scales and understanding the mechanisms hidden under low air quality (AQ) conditions is essential for tackling potential air pollution issues. In this study, the air pollution of Sivas province was analyzed with meteorological and PM2.5 data over six years to assess the city's AQ in terms of PM2.5 pollution and analyze the effect of meteorological factors on it. It was found that the winter period (January-February-November-December) of every year except 2019-which has missing data-is the period with the highest air pollution in the province. In addition, the days exceeding the daily PM2.5 limit values in 2016, 2017, 2020, and 2021 were also seen in the spring and summer months, which inclined the study to focus on additional pollutant sources such as long-range dust transport and road vehicles. The year 2017 has the highest values and was analyzed in detail. Pollution periods with the most increased episodes in 2018 were analyzed with the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) and Dust Regional Atmospheric Model (DREAM) models. As a result of the study, the average PM2.5 values in 2017 were 31.66 ± 19.2 µg/m3 and a correlation of -0.49 between temperature and PM2.5. As a result of model outputs, it was found that the inversion is intensely observed in the province, which is associated with an increase of PM2.5 during the episodes. Dust transport from northwestern Iraq and northeastern Syria is observed, especially on days with daily average PM2.5 values above 100 µg/m3. Additionally, planetary boundary layer (PBL) data analysis with PM pollution revealed a significant negative correlation (r = -0.61). Air pollutants, particularly PM2.5, were found to be higher during lower PBL levels.

Treatment of landfill leachate by using electro-Fenton method.

In this study, the effects of various operating conditions such as treatment time, DC current, initial pH, initial H(2)O(2) concentration and distance between the electrodes on treatability of landfill leachate by using electro-Fenton (EF) method were examined. The settling characteristics of waste sludge produced from the treatment were also determined. According to the results, EF method can be used efficiently for the treatment of landfill leachate by using the proper operating conditions. The best removal efficiencies were obtained when: treatment duration is 20 min, constant DC current value is 3A, H(2)O(2) concentration is 2000 mg L(-1) and the initial pH value is 3. For these conditions, 72% COD, 90% color, 87% PO(4)-P and 28% NH(4)-N removals were obtained. It was also observed that using electrode distance between 1.8 cm and 2.8 cm increases efficiency of the COD removal, significantly. Sedimentation characteristics of the waste sludge produced from the EF method is fairly good.