Five-Year Analysis of Air Pollution in Istanbul Including Also the Impact of the COVID-19 Pandemic

Abstract

INTRODUCTION: Particulate matter, sulfur dioxide, ozone, and nitrogen oxide compounds are the main air pollutants. The purpose of this research is to analyze the five-year air quality of Istanbul and examine the effect of movement restrictions due to the COVID-19 pandemic on pollutants. METHODS: The public data of the National Air Quality Observation Network has been utilized. The research has been conducted based on the five-year daily averages of PM10, NO2, and NOx pollutants for Istanbul between 2016 - 2020. The data of stations which measured for 75% and more throughout the year has been used. The effect of lockdowns enforced due to COVID-19 was revealed by comparing data of pollutants from April and May of 2020 to the same period in 2019. RESULTS: There were 12 stations between 2016 – 2018, and 39 stations in 2019 and 2020 which measured particulate matter and nitrogen oxide compounds. Only 9 stations reached the standard of measuring pollution for 75% and more throughout the year. The PM10, NO2, and NOx levels measured by all the 9 stations between 2016 - 2020 are above the limit values set by the World Health Organization (WHO). The lockdowns in 2020 have not been helping improvements in air pollution issue. However, there have been regressions of 33.4%, 59.6%, and 52.6% in the overall average particulate matter, nitrogen oxide, and nitrogen dioxide concentrations during the lockdowns between 23-26 of April, 1-3 of May, and 23-26 of May, respectively. DISCUSSION AND CONCLUSION: The air pollution issue in Istanbul has not improved in a meaningful and significant manner for the last five years. There is a significant deficiency in measuring traffic pollution. It has been found that two days long lockdowns and physical movement restrictions due to COVID-19 have significantly contributed to a significant regression in the overall concentration of air pollutants.