# Evaluation of Turkey's Road-Based Greenhouse Gas Inventory and Future Projections
## 3 Results
### Greenhouse Gas Emission Calculations from State Roads
Emission estimates were assessed for statistical reliability using RSE values. CO\({}_{2}\), NH\({}_{3}\), NO\({}_{\chi}\), PM, SO\({}_{2}\), CO, and NMVOC emissions showed low uncertainty, with RSE values generally below 10%, indicating high reliability. CO\({}_{2}\) estimates, in particular, had RSEs of 5.54% (PC), 9.49% (LCV), and 2.12% (HDV), with a total value of 3.29%. In contrast, N\({}_{2}\)O emissions exhibited high uncertainty across all categories, with RSEs of around 45%. Overall, the results confirm that most emission estimates are statistically robust, except for N\({}_{2}\)O. Figure 3 displays the distribution of overall CO\({}_{2}\), N\({}_{2}\)O, NH\({}_{3}\), NO\({}_{\chi}\), SO\({}_{2}\), CO, NMVOC, and PM emissions between 2010 and 2020, originating from vehicles that were in transit on the roadways included in the research, categorized by vehicle type. Automobiles account for 58% of all emissions. When assessing pollutant sources, PCs are shown to be responsible for 65% of N\({}_{2}\)O, 95% of NH\({}_{3}\), 59% of SO\({}_{2}\), 86% of CO, and 77% of NMVOC pollutants. In contrast, HDVs accounted for 52% of CO\({}_{2}\), 74% of NO\({}_{\chi}\), and 67% of PM pollutants. One kilogram of gasoline in a car emits 3.18 g of CO\({}_{2}\), while one kilogram of diesel fuel emits 3.14 g [34]. Compared to gasoline-powered vehicles, diesel vehicles release fewer CO\({}_{2}\) emissions. However, HDVs are accountable for 52% of CO\({}_{2}\) since diesel fuel use, in contrast to gasoline, has been on the rise over time. Given that diesel fuel is used as the primary source of energy in HDVs, it would be advantageous to implement enhancements focused on fuel to mitigate emissions of CO\({}_{2}\), NO\({}_{\chi}\), and PM. To analyze the spread of emissions from automobiles on state highways in Turkey, emission distribution maps for 2010 and 2020 were generated using QGIS. The resulting maps are shown in Figure 4. The charts clearly illustrate that the emission levels in 2010 were more significant in western and central Anatolia. Furthermore, it is evident that emissions continued to increase until 2020. The results are summarized by the item below:  
* The daily CO\({}_{2}\) ranged from 47.8 to 2429 kg in 2010 and increased from 98.74 to 3024.8 kg in 2020. In 2010, Konya province had the highest recorded CO\({}_{2}\) emissions. In contrast, Ankara province had the highest values reported in 2020. * The daily N\({}_{2}\)O in 2010 ranged from 1.21 to 69.53 kg/day, whereas in 2020, it ranged from 1.72 to 97.94 kg/day. Emissions were significantly elevated, particularly in central Turkey. In 2010, the province with the highest emissions was Bursa. In 2020, it was Antalya. * The daily CO ranged from 406.06 to 26,895.91 kg/day in 2010 and from 599.12 to 34,543.22 kg/day in 2020. In 2010, Antalya province had the highest recorded emission amount. In 2020, it was Ankara. * NH\({}_{3}\) was calculated in the range of 2.75-196.82 kg/day in 2010 and 3.63-209.54 kg/day in 2020. The highest emission quantity was calculated in Antalya in 2010 and in Ankara in 2020. * When NMVOC levels were examined, the values ranged between 64.83 and 4030.7 kg/day in 2010. Antalya has the highest calculated emissions. In 2020, there was a change between 94.42 and 5436.84 kg/day, and the highest emission was calculated in Ankara. * NOx amounts were calculated as 330.67-19,470.02 kg/day and 446.55-25,733.49 kg/day for 2010 and 2020, respectively. The calculated maximum emissions were for Konya and Ankara, respectively. * The daily quantity of PM10 was calculated to be 9.20-551.12 kg in 2010 and 15.51-835.51 kg in 2020. The provinces of Konya and Ankara had the highest emission quantities for 2010 and 2020, respectively. * In Turkey, the amount of SO\({}_{2}\) emissions was calculated to be 0.35-20.19 kg/day in 2010 and 0.44-25.30 kg/day in 2020. Antalya (in 2010) and Ankara (in 2020) were determined to have the maximum emission quantities.