Friday 3 September 12:30 > 12:45

Greenhouse gases in the urban environment of Athens, trends and sources

Dr. Aikaterini Bougiatioti Dr. Konstantinos Dimitriou Dr. Michel Ramonet Mr. Frangiskos Pierros Mr. Panagiotis Michalopoulos Dr. Eleni Liakakou Dr. Stavros Solomos Mr. Pierre-Yves Quehe Dr. Marc Delmotte Dr. Evangelos Gerasopoulos Prof. Maria Kanakidou Prof. Nikolaos Mihalopoulos
Session: 27(P) CLIMPACT: National Network for Climate Change and its impacts
CEST ID: 552 ROOM: A Paper Presentation

Yearlong greenhouse gases (CO2 and CH4) concentration measurements were performed for the first time in the city of Athens, from 21/12/2018 to 31/12/2019, and analyzed in relation to atmospheric levels, wind direction at a local, regional and long-range transport scale. Clear diurnal and seasonal variations of both greenhouse gases were detected, with elevated levels during night and early morning hours, associated with traffic/heating emissions and leakages of residential natural gas for CO2 and CH4, respectively. With the use of respective measurements at the regional background site at Finokalia, Crete, the contribution of local anthropogenic emissions within the city was estimated, compared to regional levels. For CO2, maximum levels were clearly observed during winter, suggesting an important impact of combustion of fossil fuel and especially of biomass on CO2 levels during winter. On the other hand, the local CH4 levels did not seem to exhibit a seasonal trend and were similar in all seasons, suggesting that local sources of CH4 remain quite constant year-round. Backward modeling simulations (FLEXPART) indicate an industrial zone and a petrochemical zone, situated to the north and to the west of Athens respectively, as possible CH4 regional sources as well as possible CO2 contributions from southern directions attributed to shipping emissions from the port of Piraeus. The present study provides knowledge needed for the determination of greenhouse gas emission mitigation strategies in Athens.