Polycyclic aromatic hydrocarbons (PAHs) in the atmospheres of two French alpine valleys: sources and temporal patterns

Abstract

Abstract. Alpine valleys represent some of the most important crossroads for international heavy-duty traffic in Europe, but the full impact of this traffic on air quality is not known due to a lack of data concerning these complex systems. As part of the program "Pollution des Vallées Alpines" (POVA), we performed two sampling surveys of polycyclic aromatic hydrocarbons (PAHs) in two sensitive valleys: the Chamonix and Maurienne Valleys, between France and Italy. Sampling campaigns were performed during the summer of 2000 and the winter of 2001, with both periods taking place during the closure of the "Tunnel du Mont-Blanc". The first objective of this paper is to describe the relations between PAH concentrations, external parameters (sampling site localization, meteorological parameters, sources), and aerosol characteristics, including its carbonaceous fraction (OC and EC). The second objective is to study the capacity of PAH profiles to accurately distinguish the different emission sources. Temporal evolution of the relative concentration of an individual PAH (CHR) and the PAH groups BghiP+COR and BbF+BkF is studied in order to differentiate wood combustion, gasoline, and diesel emissions, respectively. The results show that the total particulate PAH concentrations were higher in the Chamonix valley during both seasons, despite the cessation of international traffic. Seasonal cycles, with higher concentrations in winter, are also stronger in this valley. During winter, particulate PAH concentration can reach very high levels (up to 155 ng.m −3 ) in this valley during cold anticyclonic periods. The examination of sources shows the impact during summer of heavy-duty traffic in the Maurienne valley and of gasoline vehicles in the Chamonix valley. During winter, Chamonix is characterized by the strong influence of wood combustion in residential fireplaces, even ifCorrespondence to: N. Marchand (n.marchand@opgc.univ-bpclermont.fr) the temporal evolution of specific PAH ratios are difficult to interpret. Information on sources given by PAH profiles can only be considered in qualitative terms.

Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

“…This is higher than what is measured in the present study, but it shall be noted that WSOC is a very variable fraction of OC, generally representing 30 to 80% of OC and, in addition, includes most exclusively the oxygenated fraction of OC Duarte et al, 2007;Salma et al, 2007). The differences may also result from the sampling period and location especially considering the singularity of the valley of Chamonix during winter characterised by high primary emissions from both road traffic and residential heating (Marchand et al, 2004) associated with unfavourable conditions for SOA formation and chemical aging due to low temperatures (−3.5 to −15.6 • C), low solar irradiance, and a lack of long range transport of the aerosol. The relatively low carbonyl content found in 20 Chamonix OA compared to the high carbonyl functionalisation rates measured for the photooxidation experiments (6 to 11%) supports the assumption that the Chamonix winter OA is mainly of primary origin, considering the abundance of carbonyl as a marker for SOA.…”

“…Samples from a narrow alpine valley during winter appear as an interesting case study since chemical aging can be neglected as a first approximation. In addition, vehicular emissions and wood combustion can be considered as the two principal primary sources of urban background aerosol in winter (Schauer and Cass, 2000;Zheng et al, 2002) and in an alpine valley (Marchand et al, 2004;Sandradewi et al, 2008). In a first approach, the functional groups fingerprint derived from the photooxidation of o-xylene is considered here as a fair approximation for SOA in such conditions (high NO x concentrations: 178.4 ppb in average, low O 3 concentrations: 3.2 ppb in average, and low biogenic activity, as measured during our sampling campaign) (Finlayson-Pitts and Pitts, 2000;Atkinson and Arey, 2003).…”

“…The sampling site (Clos de l'Ours) has been described by Marchand et al (2004 PM 10 were colleted on 150 mm quartz fiber filters (QM-A, Whatman) using a DA-80 high volume sampler (30 m 3 h −1 ). The sampling was split in 12 h periods, from 06:00 a.m. to 06:00 p.m. (UTC) for daytime samples, and from 06:00 p.m. to 06:00 a.m. (UTC) for nighttime samples.…”

Seasonal trends and spatial variations of PM10-bounded polycyclic aromatic hydrocarbons in Veneto Region, Northeast Italy

“…PAHs are ubiquitously distributed in the troposphere due to natural combustions (e.g. volcanic activities, wildfires), although their presence in densely populated areas is largely due to anthropogenic processes including mobile sources, domestic heating, waste incineration, asphalt production, agricultural biomass burning, oil refining and many industrial activities (Boström et al, 2002;Marchand et al, 2004;Ravindra et al, 2008;Zhang and Tao, 2009). Being generally partitioned between the gaseous and particulate phases (e.g.…”

Study on Evaluvation of Benzo (a) Pyrene Soluble Fraction in Respirable Suspended Particulate Matter in Peenya Industrial Area by GCMS

“…Mass concentration may not be the most appropriate exposure parameter for the assessment of health risks of atmospheric pollution [15]. Many aromat ic compounds, commonly identified in airborne particles, are suspected genotoxic agents and carcinogens, and some of them may also cause acute health effects [16,17]. PAHs with four or more structural rings were concern treated on the fine and ultrafine particles, and various PAH investigations can be performed equally well fro m both the PM2.5 and the PM 10 samples [14].…”