Seasonal variation of carbonaceous PM2.5 in an Istanbul traffic site

Özet

The seasonal variation offine carbonaceous aerosol was evaluated in an urban traffic site in Istanbul. PM2.5samples were collected on selected days during four seasons between Jan 2017–Jan 2018. Daily PM2.5con-centrations were obtained experimentally by the gravimetric method in Beşiktaş, while hourly concentrationswere obtained from the Air Quality Monitoring Network of Istanbul in Çatladıkapı, Silivri, Kağıthane, andÜmraniye. Organic carbon (OC) and elemental carbon (EC) concentrations were determined by a thermo-opticalcarbon analyzer for samples collected in Beşiktaş. The 24-h US-EPA air quality standard of 35μgm−3wasexceeded 13, 25, 41, 42, and 57% of the time in Çatladıkapı, Silivri, Kağıthane, Ümraniye, and Beşiktaş, re-spectively. These exceedances occurred mainly during the fall and winter owing to a combination of emissionsfrom fuel combustion for residential heating, traffic and industry, and poor air dispersion due to weak atmo-spheric motion and low mixing heights. Average OC concentrations ranged as 6.62–7.32μgm−3during springand summer, and 13.76–14.1μgm−3during fall and winter. The OC concentrations observed in this workduring the summer and winter were 2–4 and 3–6 times higher than concentrations observed in the USA andEurope, respectively. The EC concentrations did not show considerable seasonal variation, with values between2.16 and 3.26μgm−3. EC concentrations in Beşiktaşwere 7 and 9 times higher than concentrations observed inthe USA and Europe, in order. Results obtained in this study could be helpful for future implementation ofpolicies and strategies to reduce emissions from combustion sources in order to comply with the air qualitystandards.