A study by researchers at Istanbul Technical University (ITU) found that sulfur dioxide concentrations in Istanbul fell by about 24% between 2016 and 2025, reflecting the impact of energy transition and emission control policies.
The study analyzed data from air quality monitoring stations operated by the Ministry of Environment, Urbanization and Climate Change and the Istanbul Metropolitan Municipality. According to the findings, the city's average sulfur dioxide concentration declined from 5.4 micrograms per cubic meter in 2016 to 4.1 micrograms per cubic meter in 2025, a statistically significant decrease.
Researchers found that sulfur dioxide, once one of Istanbul's main air pollution indicators, now remains at much lower levels. However, the decline was not uniform across the city, with only the Kandilli monitoring station recording a statistically significant decrease after detailed analysis.
The study also showed that sulfur dioxide levels were higher during winter, averaging 4.9 micrograms per cubic meter, compared with 3.8 micrograms per cubic meter in summer. Researchers attributed the seasonal increase to residential heating and weather conditions that allow pollutants to accumulate in the atmosphere.
