Variability in regional background aerosols within the Mediterranean

The main objective of this study is the identification of major factors controlling levels and chemical composition of aerosols in the regional background (RB) along the Mediterranean Basin (MB). To this end, data on PM levels and speciation from Montseny (MSY, NE Spain), Finokalia (FKL, Southern Greece) and Erdemli (ERL, Southern Turkey) for the period 2001 to 2008 are evaluated. Important differences on PM levels and composition are evident when comparing the Western and Eastern MBs. The results manifest W-E and N-S PM(10) and PM(2.5) gradients along the MB, attributed to the higher frequency and intensity of African dust outbreaks in the EMB, while for PM(1) very similar levels are encountered

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Secondary organic aerosol origin in an urban environment: influence of biogenic and fuel combustion precursors

International audienceSource contributions of organic aerosol (OA) are still not fully understood, especially in terms of quantitative distinction between secondary OA formed from anthropogenic precursors vs. that formed from natural precursors. In order to investigate the OA origin, a field campaign was carried out in Barcelona in summer 2013, including two periods characterized by low and high traffic conditions. Volatile organic compound (VOC) concentrations were higher during the second period, especially aromatic hydrocarbons related to traffic emissions, which showed a marked daily cycle peaking during traffic rush hours, similarly to black carbon (BC) concentrations. Biogenic VOC (BVOC) concentrations showed only minor changes from the low to the high traffic period, and their intra-day variability was related to temperature and solar radiation cycles, although a decrease was observed for monoterpenes during the day. The organic carbon (OC) concentrations increased from the first to the second period, and the fraction of non-fossil OC as determined by C-14 analysis increased from 43% to 54% of the total OC. The combination of C-14 analysis and Aerosol Chemical Speciation Monitor (ACSM) OA source apportionment showed that the fossil OC was mainly secondary (> 70%) except for the last sample, when the fossil secondary OC only represented 51% of the total fossil OC. The fraction of non-fossil secondary OC increased from 37% of total secondary OC for the first sample to 60% for the last sample. This enhanced formation of non-fossil secondary OA (SOA) could be attributed to the reaction of BVOC precursors with NOx emitted from road traffic (or from its nocturnal derivative nitrate that enhances night-time semi-volatile oxygenated OA (SV-OOA)), since NO2 concentrations increased from 19 to 42 mu g m(-3) from the first to the last sample

Intercomparison of source apportionment approaches within the EU\u2010MED APICE project

The EU-MED APICE project (Common Mediterranean strategy and local practical Actions for the mitigation of Port, Industries and Cities Emissions; www.apiceproject.eu) aims to quantify the impact of harbour and harbour related activities to PM concentration observed in 5 Mediterranean harbours: Barcelona (Spain), Marseille (France), Genoa (Italy), Venice (Italy) and Thessaloniki (Greece). For that purpose, long term monitoring campaigns are currently underway in these 5 harbours by each of the local scientific partner of the project. In order to intercompare source apportionment approaches used by each partner and to harmonize the methodologies between areas under study, a 6 weeks intercomparison campaign has been conducted in Marseille during winter 2011. Marseille is the most important harbour of the Mediterranean Sea. It handles twice the traffic compared to Genoa, and nearly three times the traffic of Barcelona or Valencia. A huge petrochemical area, among other industrial plants (steel mill, coke plant...), is also located close to Marseille, the second most populated city in France with more than 1 million inhabitants. Industrial and shipping emissions of PM are generally among the least well known sources in the field of atmospheric research and largely merit in depth studies in this context. Furthermore, this intercomparison campaign is also the ideal framework to test our ability to apportion such specific sources among many others in a densely populated area. Comprehensive chemical characterization of PM2.5 and PM10 have been performed by each partner on the same 24h basis during this 6 week-long campaign, including measurements of major ions, OC/EC, metals/elements and organic markers (hopanes, levoglucosan, PAHs, n-alkanes, fatty acids, resin acids, methoxy phenol,..). Independent results from each partner are now intercompared. High temporal resolution measurements were also achieved with high-resolution time-of-flight aerosol mass spectrometers (HR-ToFAMS), aethalometer, multi-angle absorption photometer ( AAP), scanning mobility particle sizer (SMPS) and proton transfer reaction mass spectrometer (PTR-MS) for VOC measurements. Positive Matrix Factorization (PMF) and Chemical Mass Balance (CMB) were used to apportion sources. Preliminary example of source apportionment is presented with figure 1. In this presentation, we will compare several source apportionment approaches: - CMB with organics markers and elements/metals, - PMF with elements/metals and major aerosol fractions (OC/EC, major ons), - PMF with elements/metals, organic markers and major aerosol fractions (OC/EC, major ions) (figure 1), - AMS/PMF. Combination of CMB and PMF has also been performed (i.e. factors derived from PMF analysis have been injected as source profiles in CMB calculation). This combined approach is particularly interesting for sources such as mineral or road dust, for which no source profile exists or presents too much variability between environments to be considered as scientifically sounded)

Short-term effects of particulate matter on mortality during forest fires in Southern Europe: Results of the MED-PARTICLES project

Background: An association between occurrence of wildfires and mortality in the exposed population has been observed in several studies with controversial results for cause-specific mortality. In the Mediterranean area, forest fires usually occur during spring-summer, they overlap with Saharan outbreaks, are associated with increased temperature and their health effects are probably due to an increase in particulate matter. Aim and methods: We analysed the effects of wildfires and particulate matter (PM10) on mortality in 10 southern European cities in Spain, France, Italy and Greece (2003-2010), using satellite data for exposure assessment and Poisson regression models, simulating a case-crossover approach. Results: We found that smoky days were associated with increased cardiovascular mortality (lag 0-5, 6.29%, 95% CIs 1.00 to 11.85). When the effect of PM10 (per 10 mg/m3) was evaluated, there was an increase in natural mortality (0.49%), cardiovascular mortality (0.65%) and respiratory mortality (2.13%) on smoke-free days, but PM10-related mortality was higher on smoky days (natural mortality up to 1.10% and respiratory mortality up to 3.90%) with a suggestion of effect modification for cardiovascular mortality (3.42%, p value for effect modification 0.055), controlling for Saharan dust advections. Conclusions: Smoke is associated with increased cardiovascular mortality in urban residents, and PM10 on smoky days has a larger effect on cardiovascular and respiratory mortality than on other days

Mechanisms of Climate Variability, Air Quality and Impacts of Atmospheric Constituents in the Mediterranean Region

This chapter describes the physicochemical mechanisms that formulate the air quality over the Mediterranean region and the resulted impacts on the regional climate. At first, a detailed description of the teleconnections and regional flow patterns that dominate in the region is provided. The dominant flow patterns during the different seasons of the year determine the transport paths of air pollutants and aerosols towards and across the study area. The analysis on the characteristics of the air pollution transport is separated for the different parts of the Mediterranean region (eastern, western and entire), since the sources of pollutants that reach at different points in the region vary, while specific pollutant transport paths may influence the wider Mediterranean area. Similarities and differences in patterns are discussed. The air quality over the region, as recorded from black/organic carbon, ozone, aerosol observations, is extensively discussed, along with seasonal variabilities and annual trends. There is particular discussion on the suspension of naturally-produced aerosols and especially desert dust particles in the region and their spatial influence on the aerosol levels. At the last part of the chapter, the major impacts of the transport and transformation processes (natural and anthropogenic pollutants) on the regional climate are discussed. The impacts of aerosols are distinguished in direct (the impacts on radiation budget), health (the amounts of inhaled particles and impacts on health) and indirect effects (impacts on clouds and precipitation), are discussed on qualitative and quantitative way. © 2013, Springer Science+Business Media Dordrecht