Elemental Composition and Source Apportionment of Fine and Coarse Particles at Traffic and Urban Background Locations in Athens, Greece

Georgios Grivas; Stavros Cheristanidis; Archontoula Chaloulakou; Petros Koutrakis; Nikos Mihalopoulos

doi:10.4209/aaqr.2017.12.0567

Elemental Composition and Source Apportionment of Fine and Coarse Particles at Traffic and Urban Background Locations in Athens, Greece

$Bivariate polar plots for conditional probabilities of threshold exceedance, for fractional source contributions estimated at the urban background site, regarding the road traffic (TRA), biomass burning (BB) and oil combustion (OIL) sources in PM2.5.$

Georgios Grivas ¹^,2, Stavros Cheristanidis², Archontoula Chaloulakou², Petros Koutrakis³, Nikos Mihalopoulos¹^,4

¹Institute for Environmental Research and Sustainable Development, National Observatory of Athens, 15236 Athens, Greece
²School of Chemical Engineering, National Technical University of Athens, 15780 Athens, Greece
³Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
⁴Environmental Chemistry Processes Laboratory, Department of Chemistry, University of Crete, 71003 Heraklion, Greece

Received: December 8, 2017
Revised: February 6, 2018
Accepted: February 8, 2018
Download Citation: ||https://doi.org/10.4209/aaqr.2017.12.0567

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Cite this article:
Grivas, G., Cheristanidis, S., Chaloulakou, A., Koutrakis, P. and Mihalopoulos, N. (2018). Elemental Composition and Source Apportionment of Fine and Coarse Particles at Traffic and Urban Background Locations in Athens, Greece. Aerosol Air Qual. Res. 18: 1642-1659. https://doi.org/10.4209/aaqr.2017.12.0567

HIGHLIGHTS

Large roadside increments for toxic trace elements at fine and coarse size ranges.
Inter-site discrepancies in relative inputs of traffic and regional/secondary sources.
Natural sources account for 8–13% of PM₁₀ indicating limits to regulatory compliance.
High inter-site temporal covariance but different levels of net source contributions.
Control of traffic emissions could produce significant effects for the greater area.

ABSTRACT

Athens is one of the European cities most burdened by particle pollution; thus, characterizing the aerosol composition and sources is imperative for addressing health concerns and undertaking mitigation measures. In this study, PM₁₀ and PM_2.5 ambient samples, collected at a roadside traffic and at an urban background site throughout an annual period, were analyzed for their elemental composition and light-absorbing carbon. Positive Matrix Factorization (PMF) analysis was performed to identify sources and quantify their contributions to the PM_2.5 and PM_10–2.5 fractions. Above a two-fold roadside enhancement of concentrations was observed for a number of vehicle-emitted and road-dust resuspended species (BC, Cu, Zn, Fe and Ca), with increments for trace elements being more notable in the coarse fraction. Source apportionment indicated that road traffic and sulfate-rich regional aerosols were the key contributors to the fine particles, with the former being dominant at the roadside site (43%) and the latter accounting for the majority (52%) of the particle mass at the background location. Other fine particle sources included biomass burning -mainly during wintertime-, heavy oil combustion, mineral dust and sea salt. For coarse particles, the PMF-extracted factors were associated with vehicular emissions and road dust (prevailing at the roadside site, with a combined contribution of 60%), mineral dust and sea salt (52% cumulatively at the background site). Regional contributions of secondary and natural particles were comparable in level and well correlated among the sites. On the contrary, the net contributions from traffic related sources exhibited large concentration gradients; however, high spatial correlations were observed, especially in cases with favorable wind circulations from the city center towards the background site. It appears that controlling traffic related emissions, in the absence of significant point sources in the area, could have a pronounced effect on a wide spatial scale within Athens, with broad implications for the protection of public health.

Keywords: PM2.5; PM10-2.5; XRF; Spatial variability; Receptor modelling.