Evaluation of the effects of Covid-19 lockdowns and strict restrictions on İstanbul's air quality

Abstract

The Covid-19 pandemic, which started in Wuhan, China, led to several strict restrictions and lockdowns in Turkey, like many other countries. Although lockdowns have had a socially and economically negative impact, they have affected the air quality in a positive way. The aim of this study is to examine the spatial impact of lockdowns on air quality in İstanbul and to determine the correlation of polluting indicators. In line with the determined purpose, PM10, SO2, NO2, CO and NOx parameters were spatialized with ordinary kriging method in 5 different time intervals and the relativity levels between meteorology, transportation and particles that cause pollution were examined with the Pearson correlation method. As a result, lockdowns caused an increase on CO and SO2 by up to 28%, while other particles decreased by 2% to 23%. Compared to 2019, a decrease of up to 60% in all particles except CO and SO2 has shown that lockdowns have a positive effect on air quality. It was observed that the pollution, which was concentrated in urban areas before the pandemic, spread to rural areas with the precautions taken. Temperature, number of vehicles and traffic index were found to play an important role in the emission of particles, while wind speed and direction played an important role in the displacement of pollution. It has been observed that finding a positive correlation between pollutants and the factors that trigger pollution has rapidly changed the ecosystem of the city along with the policies affecting air quality.