Characterization and source apportionment of carbonaceous aerosols in fine particles at urban and suburban atmospheres of Ankara, Turkey

Impact of COVID-19 lockdown on carbonaceous aerosols in a polluted city: Composition characterization, source apportionment, influence factors of secondary formation

“…OC3 of LP was significantly lower throughout the day, which was closely related to vehicle emissions ( Qi et al, 2018 ; Koçak et al, 2021 ). OC1, OC2, and OC3 all showed daily variation characteristics of lower daytime concentrations than nighttime concentrations during the two periods, which might be due to the more accumulation and less dispersion of the pollutants at the night.…”

“…Almost all the EC x had higher concentrations during NP than during LP, with the largest difference for EC3, followed by EC4, EC2, and EC1, with little difference for EC5 and EC6. Combined with the source emission changes during LP, it was assumed that the reduction in EC x was mainly caused by the reduction in anthropogenic primary source emissions, such as vehicle emission and industry ( Chatterjee et al, 2021 ; Koçak et al, 2021 ). Detailed discussions are in Text S3.…”

“…Liu et al (2006) also researched that OC (120 °C) and OC (250 °C) were partially associated with coal combustion. In addition, Koçak et al (2021) attributed OC2 (310–475 °C) partially to coal combustion, and SO 2 and CO were evident tracers from coal combustion ( Vodička et al, 2015 ). There was also some EC1 loading (17% and 60%) in this factor, which also accorded with the previous study conducted in Haikou, China ( Liu et al, 2018 ).…”

“…The chemical profile of factor 3 was defined by NO 2 (the loadings of 80% and 70% during the normal and lockdown periods), EC1 (the loadings of 76% and 40%), OC2 (the loadings of 54% and 52%), and OC3 (the loadings of 60% and 32%), mainly derived from gasoline vehicles ( Chow et al, 2004 ; Cao et al, 2005 ; Mcdonald et al, 2013 ; Liu et al, 2018 ; Koçak et al, 2021 ). Thus, factor 3 was identified as the emissions of gasoline vehicles, and this factor was the major contributor to OC (44% and 37%) and TC (47% and 37%) across all the research periods.…”

“…The main carbonaceous fractions defining factor 5 were EC2, EC3, and EC4, which were closely related to diesel vehicle emissions ( Liu et al, 2018 ; Qi et al, 2018 ; Koçak et al, 2021 ). Also, the partial apportionment of NO 2 in this factor suggested the emission of diesel vehicles.…”