Elemental and organic carbon in the urban environment of Athens. Seasonal and diurnal variations and estimates of secondary organic carbon

Grivas, G; Cheristanidis, S; Chaloulakou, A

dc.contributor.author	Grivas, G	en
dc.contributor.author	Cheristanidis, S	en
dc.contributor.author	Chaloulakou, A	en
dc.date.accessioned	2014-03-01T02:08:51Z
dc.date.available	2014-03-01T02:08:51Z
dc.date.issued	2012	en
dc.identifier.issn	00489697	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29732
dc.subject	Athens	en
dc.subject	EC tracer method	en
dc.subject	Elemental carbon	en
dc.subject	Organic carbon	en
dc.subject	Secondary organic aerosol (SOA)	en
dc.subject	Urban air pollution	en
dc.subject.other	Athens	en
dc.subject.other	Elemental carbon	en
dc.subject.other	Secondary organic aerosols	en
dc.subject.other	Tracer methods	en
dc.subject.other	Urban air pollution	en
dc.subject.other	Air pollution	en
dc.subject.other	Atmospheric aerosols	en
dc.subject.other	Carbon	en
dc.subject.other	Fog	en
dc.subject.other	Particles (particulate matter)	en
dc.subject.other	Photochemical forming	en
dc.subject.other	Radioactive tracers	en
dc.subject.other	Transportation	en
dc.subject.other	Organic carbon	en
dc.subject.other	carbon	en
dc.subject.other	elemental carbon	en
dc.subject.other	organic carbon	en
dc.subject.other	organic matter	en
dc.subject.other	secondary organic carbon	en
dc.subject.other	unclassified drug	en
dc.subject.other	aerosol	en
dc.subject.other	atmospheric pollution	en
dc.subject.other	concentration (composition)	en
dc.subject.other	correlation	en
dc.subject.other	diurnal variation	en
dc.subject.other	organic carbon	en
dc.subject.other	photochemistry	en
dc.subject.other	regression analysis	en
dc.subject.other	sea breeze	en
dc.subject.other	seasonal variation	en
dc.subject.other	tracer	en
dc.subject.other	urban pollution	en
dc.subject.other	air pollutant	en
dc.subject.other	air pollution	en
dc.subject.other	airflow	en
dc.subject.other	article	en
dc.subject.other	calculation	en
dc.subject.other	circadian rhythm	en
dc.subject.other	concentration (parameters)	en
dc.subject.other	controlled study	en
dc.subject.other	Greece	en
dc.subject.other	measurement	en
dc.subject.other	priority journal	en
dc.subject.other	seasonal variation	en
dc.subject.other	secondary organic aerosol	en
dc.subject.other	traffic	en
dc.subject.other	urban area	en
dc.subject.other	wind	en
dc.subject.other	Athens [Attica]	en
dc.subject.other	Attica	en
dc.subject.other	Greece	en
dc.title	Elemental and organic carbon in the urban environment of Athens. Seasonal and diurnal variations and estimates of secondary organic carbon	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.scitotenv.2011.10.058	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.scitotenv.2011.10.058	en
heal.publicationDate	2012	en
heal.abstract	Elemental and organic carbon (EC and OC) hourly concentrations were measured continuously, at an urban location in central Athens, Greece, for an 8-month period (January-August). Average concentrations of 2.2μgCm-3 and 6.8μgCm-3 were observed, for EC and OC, respectively. The combined contribution of carbonaceous compounds (EC plus organic matter) to PM10 was calculated at 26%. The seasonal variability of EC was limited, while OC mean concentrations were significantly higher (by 23%), during the warm months (May-August). The weekly variation followed a different pattern, with the weekend decrease of EC levels (25%) being more pronounced than of OC (14%). EC produced a bimodal diurnal cycle, with the morning rush hour traffic mode prevailing. The OC mean circadian variation displayed those peaks as well. However, midday-to-afternoon presence of secondary organic aerosol (SOA) was strongly indicated. The conditional probability function was used to assess the impact of wind direction. High EC, OC levels were linked to southern flows, which during summer are mainly related to the appearance of sea breeze circulation. The temporal variation of EC, OC and their correlation patterns with primary and secondary gaseous pollutants, suggested that, although primary emissions affected both fractions, SOA formation is an important factor to be accounted for, especially during the photochemical season. Secondary organic carbon was estimated using the EC tracer method and orthogonal regression on OC, EC hourly concentration data. The average contributions of secondary organic carbon (SOC) to OC were calculated at 20.9% for the cold period and 30.3% for the warm period. Maximum values of 58% and 91% were estimated for daily and hourly contributions, respectively. The SOC diurnal variations suggested photochemical formation throughout the year, intensified during summer months, with the correlation coefficient between SOC and the sum of oxidants (NO2+O3) reaching up to 0.84. © 2011 Elsevier B.V.	en
heal.journalName	Science of the Total Environment	en
dc.identifier.doi	10.1016/j.scitotenv.2011.10.058	en
dc.identifier.volume	414	en
dc.identifier.spage	535	en
dc.identifier.epage	545	en