Temporal Variation of Particulate and Gaseous Air Pollutants in the Industrialized Region of Kocaeli: Long-term Air Pollution Trend (2019-2023)

Ambient air pollution is a global problem that adversely affects human health and causes premature death. In this study, for the first time, the air quality of K & ouml;rfez region in Kocaeli, an industrialized city in Turkey, was investigated during 2019-2023. The annual and monthly variations of PM10, PM2.5, SO2, NO2, and O-3 concentrations in the region were investigated. Average daily maximum 8 h average concentration values for O-3 were calculated due to the high average O-3 concentration, especially in the months representing the summer season (June, July, and August). The concentration values of five air pollutants were compared with the limit values specified in the 2005 World Health Organization Air Quality Guidelines (2005 WHO AQG), 2021 WHO AQG, and Turkish national legislation. Pearson correlation analysis was performed to determine the relationship between the concentrations of air pollutants. The annual average PM10 and PM2.5 concentrations exceeded the limit values recommended by WHO during 2019-2023. In 2022 and 2023, the annual average PM10 concentrations were 2.54 and 2.53 times higher than the limit values in the 2021 WHO AQG, while PM2.5 concentrations were 3.4 and 3.7 times higher. Average NO2 concentration was 3.58 and 2.71 times higher than the 2021 WHO AQG in 2022 and 2023, respectively. The average SO2 concentration (< 13.2 <mu>g/m(3)) did not exceed both WHO and national limit values for five years. The study demonstrated that in the study area exposure to PM10, PM2.5 and NO2 pollution is higher during the colder seasons, while exposure to O-3 pollution is higher during the summer season. Especially in July and August, the number of exceedances of the daily maximum 8-h O-3 concentration of 100 mu g/m(3) was higher. There were positive strong-very strong correlations between PM10-PM2.5, PM10-NO2, and PM2.5-NO2, while there were negative and moderate correlations between PM2.5-O-3 and NO2-O-3. Considering the concentration of air pollutants in the K & ouml;rfez region and the limit values for air pollutants, the people in this region face serious health risks, especially respiratory diseases, due to PM10, PM2.5, NO2 and O-3 pollution. These air pollutants may pose an additional health risk, especially for individuals with respiratory diseases in this region.