Source apportionment of fine PM and sub-micron particle number concentrations at a regional background site in the western Mediterranean: a 2.5 year study

Abstract

The chemical composition and sources of ambient fine particulate matter (PM₁) over a period of 2.5 years for a regional background site in the western Mediterranean are presented in this work. Furthermore, sub-micron particle number concentrations and the sources of these particles are also presented. The mean PM₁ concentration for the measurement period was 8.9 μg m⁻³, with organic matter (OM) and sulphate comprising most of the mass (3.2 and 1.5 μg m⁻³ respectively). Six sources were identified in PM₁ by Positive Matrix Factorisation (PMF): secondary organic aerosol, secondary nitrate, industrial, traffic + biomass burning, fuel oil combustion and secondary sulphate. Typically anthropogenic sources displayed elevated concentrations during the week with reductions at weekends. Nitrate levels were elevated in winter and negligible in summer, whereas secondary sulphate levels underwent a contrasting seasonal evolution with highest concentrations in summer, similar to the fuel oil combustion source. The SOA source was influenced by episodes of sustained pollution as a result of anticyclonic conditions occurring during winter, giving rise to thermal inversions and the accumulation of pollutants in the mixing layer. Increased levels in summer were owing to higher biogenic emissions and regional recirculation of air masses. The industrial source decreased in August due to decreased emissions during the vacation period. Increases in the traffic + biomass burning source were recorded in January, April and October, which were attributed to the occurrence of the aforementioned pollution episodes and local biomass burning emission sources, which include agriculture and domestic heating systems. Average particle number concentrations (N_{9-825 nm}) from 5/11/2010 to 01/06/2011 and from 15/10/2011 to 18/12/2011 reached 3097 cm⁻³. Five emission sources of particle of sub-micron particles were determined by Principal Component Analysis (PCA); industrial + traffic + biomass burning, new particle formation + growth, secondary sulphate + fuel oil combustion, crustal material and secondary nitrate. The new particle formation + growth source dominated the particle number concentration (56% of total particle number concentration), especially for particles < 100 nm, followed by industrial + traffic + biomass burning (13%). Secondary sulphate + fuel oil combustion (8%), nitrate (9%) and crustal material (2%) were dominant for particles of larger diameter (> 100 nm) and thus did not influence the particle number concentration significantly

Spatial extent of new particle formation events over the Mediterranean Basin from multiple ground-based and airborne measurements

“…New particle formation (NPF) events have been widely observed in the atmosphere in different environments from remote areas at high altitude or latitude to polluted environments in different climates (Pey et al, 2008;Manninen et al, 2010;Yli-Juuti et al, 2011;Cusack et al, 2013). However, the exact mechanism and chemical species involved in the NPF process are not fully identified, especially regarding the diversity of environments to consider.…”

“…Although the Mediterranean area is particularly sensitive to the future evolution of atmospheric pollutants and climate change, only a few studies related to NPF in this area have been reported so far. Intensive campaigns were conducted on the eastern Spanish coast, in Barcelona and at the Montseny site (Pey et al, 2008;Cusack et al, 2013), while long-term measurements are performed at the Finokalia (Crete) station (Kalivitis et al, 2008(Kalivitis et al, , 2015Manninen et al, 2010;Pikridas et al, 2012), where NPF event days are close to 30 %. The Mediterranean Basin is at the cross section of many different influences: there is a strong anthropogenic influence from densely populated coastal zones, in addition to marine and dust sources, as well as with emissions from Mediterranean forests and shrublands that emit both terpenes and isoprene.…”

PM&lt;sub&gt;1&lt;/sub&gt; measurements at a site close to an oil/gas pre-treatment plant (Agri Valley – southern Italy): a preliminary study

“…3). By comparing the mean value of the PM 1 daily concentrations registered in Viggiano with those reported in other studies, it can be observed that it is generally lower than those found at other sites (Cusack et al, 2013;Onat et al, 2013;Perrone et al, 2014;Theodosi et al, 2011;Caggiano et al, 2010;Pérez et al, 2008a, b;Marenco et al, 2006;Gomišček et al, 2004) and, in particular, it is lower than the PM 1 concentration mean value (11.0±5.1 µg m −3 ) measured close to the COVA plant from July to November 2011 (Trippetta et al, 2013). Regarding the latter, this could be due to the combination of two factors: the geographical position of Viggiano with respect to the COVA plant, and the wind features of the area.…”

“…The presence of K may also suggest the influence of the biomass and wood burning in this component. In fact, K is the most common inorganic species used to trace this kind of source (Cusack et al, 2013;Kim et al, 2010). Therefore, PC 1 identifies the PM 1 crustal fraction, with a minor contribution of biomass and wood burning.…”

The Association between Intermodal (PM1-2.5) and PM1, PM2.5, Coarse Fraction and Meteorological Parameters in Various Environments in Central Europe

“…The summer environmental category urban_TSP, where PM 1-2.5 also depended on PM 1 , included measurement sites heavily influenced by exhaust emission from traffic and, thus, dominant PM 1 source (for instance: Guigliano et al, 2005;Pérez et al, 2010;Ondráček et al, 2011;Cusack et al, 2013). On the other hand, the second summer urban (urban_PM 10 ) environment represented only one measurement site directly situated closed to university botanical garden (35,000 m 2 ).…”