Assessment of ground-level ozone pollution in Türkiye according to new WHO limits.

Ground-level ozone is a secondary pollutant and is attributable to respiratory diseases and mortality. For this reason, the World Health Organization (WHO) implemented a new long-term (peak season) limit value for ozone. The previous studies related to ozone in Türkiye were spatially limited to certain locations. In this study, annual mean and peak season ozone concentrations, and limit exceedances were investigated for Türkiye for the year 2021. Moreover, ozone peak seasons were determined for the first time for 126 air quality monitoring stations. The annual mean ozone concentration was determined as 44.3 ± 19.3 µg/m3 whereas the peak season average ozone level was 68.4 ± 27.2 µg/m3. April-September period was the most frequently observed ozone peak season. Among all stations, Erzurum Palandöken was by far the most polluted station in terms of annual mean and limit exceedances of ozone. Ankara Siteler stations have the highest rank in peak season mean. 87 and 83 stations exceeded the short-term and long-term recommendations of WHO, respectively. Four hotspot regions were revealed in terms of peak season exceedance: Adana and surrounding provinces, the surroundings of Burdur and Isparta provinces, and the northeastern and northwestern parts of Türkiye. To protect public health, WHO recommendations for 8-h and peak season limits should be immediately implemented in Turkish regulations.

Investigating the long-term trends in aerosol optical depth and its association with meteorological parameters and enhanced vegetation index over Turkey.

Aerosol optical depth (AOD) provides useful information on particulate matter pollution at both regional and global levels. In this study, the long-term datasets of aerosols, meteorological parameters, and enhanced vegetation index (EVI) were used from September 2002 to December 2021 over Turkey. This study examined the spatiotemporal distribution of aerosols and their association with meteorological parameters (temperature (Temp), relative humidity (RH), wind speed (WS)), and EVI over Turkey from 2002 to 2021. Moreover, this study also performed a comparison of AOD retrieved from Aqua with other satellites (Terra, SeaWiFS, and MISR) and ground-based (AERONET) products. The higher mean seasonal AOD (> 0.3) was observed over Southeastern Anatolia Region due to the dust transport from the Saharan Desert and Arabian Peninsula. Moreover, AOD was positively correlated with Temp and WS in the east of Turkey, while negative correlations were observed in the coastal regions. The correlation between AOD and RH was also observed negative in most parts of Turkey. Furthermore, in the coastal region, the correlation between AOD and EVI was found to be positive, whereas a negative correlation was seen over less vegetative areas. The multi-seasonal AOD averages were calculated as 0.187, 0.183, 0.138, and 0.104 for the spring, summer, autumn, and winter seasons, respectively. The most important result of this study is the regional differences in AOD over Turkey. For new studies, AOD should be observed separately for coastal areas and the eastern part of Turkey.

Modeling of PM10 emissions from motor vehicles at signalized intersections and cumulative model validation.

Motor vehicle emissions especially occur at signalized intersections during idling, acceleration, and deceleration phases. The reduction of exhaust emissions from motor vehicles is on the focus of environmental studies. The main targets of this paper are the modeling of motor vehicle particulate matter (PM10) emissions by American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) and California Line Source for Queuing and Hot Spot Calculations (CAL3QHCR) models and investigating the effectiveness of a hypothetical green wave scenario as a pollution reduction strategy. The portion of D010 State Road in Zonguldak (Turkey) is selected. Vehicle counting is applied for determining the traffic volume. Then, the PM10 emission inventory is prepared. After that, PM10 pollution distribution maps at signalized intersections are created by running air quality models. Next, the CAL3QHCR model is run again for the green wave scenario which assumes free flow at signalized intersections. The maximum PM10 concentrations predicted by AERMOD and CAL3QHCR models are 16.8 µg/m3 and 14.9 µg/m3, respectively. Although these values are below the threshold value, it can be said that air quality may pose a threat to public health in the existence of other sources. With the implementation of signal optimization, the PM10 pollution is reduced by 10-50% at intersections. Cumulative model validation is employed including other PM10 sources in the study area. PM10 contribution of other sources at Zonguldak air quality monitoring station is determined by the AERMOD model. Finally, the sum of model outputs is validated against measured concentrations. According to the validation, both models are found as satisfactory and AERMOD performed better than CAL3QHCR.

Cost analysis of plastic solid waste recycling in an urban district in Turkey.

The usage of plastics has exponentially increased in our daily lives over the past 50 years because of its durability, low costs and potential for diverse applications, such as widespread use as disposable items. In this study, first, the recycling cost of plastic wastes has been estimated by using actual data taken from a recycling centre, where plastic solid wastes were collected separately. The total amount of plastic wastes recycled at the centre was approximately 695 tonnes. The operating cost of plastics separation at the recycling centre, the transport of plastic wastes, labouring, maintenance, electricity, insurance and chemical costs were taken into consideration in the cost evaluation. Accordingly, the unit cost of recycling was calculated as US$0.40 kg-1 of plastic waste. This cost was compared with the predicted plastic recycling cost in the same region using statistical values. The predicted recycling cost was estimated based on assuming segregated collection by the municipalities of all PSW in municipal solid waste. Then the resulting unit cost of recycling was found to be US$0.25 kg-1 of plastic waste. In addition, the recycling costs were also evaluated including the revenue from the sales of recycled plastic granular. According to the evaluated total cost of plastic recycling, it can be concluded that mechanical recycling of plastics can only be an economical option if the recovery of plastics is improved.