Is systemic lupus erythematosus different in urban versus rural living environment? Data from the Cretan Lupus Epidemiology and Surveillance Registry.

BACKGROUND: Examining urban-rural differences can provide insights into susceptibility or modifying factors of complex diseases, yet limited data exist on systemic lupus erythematosus (SLE). OBJECTIVE: To study SLE risk, manifestations and severity in relation to urban versus rural residence. METHODOLOGY: Cross-sectional analysis of the Crete Lupus Registry. Demographics, residency history and clinical data were obtained from interviews and medical records ( N=399 patients). Patients with exclusively urban, rural or mixed urban/rural residence up to enrolment were compared. RESULTS: The risk of SLE in urban versus rural areas was 2.08 (95% confidence interval: 1.66-2.61). Compared with rural, urban residence was associated with earlier (by almost seven years) disease diagnosis - despite comparable diagnostic delay - and lower female predominance (6.8:1 versus 15:1). Rural patients had fewer years of education and lower employment rates. Smoking was more frequent among urban, whereas pesticide use was increased among rural patients. A pattern of malar rash, photosensitivity, oral ulcers and arthritis was more prevalent in rural patients. Residence was not associated with organ damage although moderate/severe disease occurred more frequently among rural-living patients (multivariable adjusted odds ratio: 2.17, p=0.011). CONCLUSION: Our data suggest that the living environment may influence the risk, gender bias and phenotype of SLE, not fully accounted for by sociodemographic factors.

A direct method to quantify methanol-soluble organic carbon for brown carbon absorption studies.

The current research provides a newly developed method to quantify methanol-soluble organic carbon (MeS_OC) in aerosol samples. This analytical procedure allows an accurate separation of MeS-OC component, which is critical for the calculation of mass absorption efficiency (MAE) of ambient Brown Carbon (BrC) and consequently its climate relevant potential. The method includes extraction, filtering and condensation stages, leading to the preparation of a highly concentrated product in which MeS-OC can be precisely quantified by a Sunset Carbon Analyzer in a single analysis step. This method can be applied on aerosol collected using either high or low volume samplers, since a relatively small filter area is required for the determination. Furthermore, it eliminates any misestimation of the MeS-OC mass that may appear in other reported techniques that don't seem to include the precise separation of methanol-soluble fraction in their quantification process.•The mass quantification of methanol-soluble organic carbon is essential, contributing up to 50% to the absorptivity of organic aerosol (BrC) at shorter wavelengths.•The method provides a direct measurement of methanol-soluble aerosol components, resolving any potential uncertainties of previously applied methods.•The adoption of this direct quantification approach leads to a rationalization of past MAE estimates for BrC with implications for radiative transfer models.

Brown carbon absorption and radiative effects under intense residential wood burning conditions in Southeastern Europe: New insights into the abundance and absorptivity of methanol-soluble organic aerosols.

Biomass burning is a major source of Brown Carbon (BrC), strongly contributing to radiative forcing. In urban areas of the climate-sensitive Southeastern European region, where strong emissions from residential wood burning (RWB) are reported, radiative impacts of carbonaceous aerosols remain largely unknown. This study examines the absorption properties of water- and methanol-soluble organic carbon (WSOC, MeS_OC) in a city (Ioannina, Greece) heavily impacted by RWB. Measurements were performed during winter (December 2019 - February 2020) and summer (July - August 2019) periods, characterized by RWB and photochemical processing of organic aerosol (OA), respectively. PM2.5 filter extracts were analyzed spectrophotometrically for water- and methanol-soluble BrC (WS_BrC, MeS_BrC) absorption. WSOC concentrations were quantified using TOC analysis, while those of MeS_OC were determined using a newly developed direct quantification protocol, applied for the first time to an extended series of ambient samples. The direct method led to a mean MeS_OC/OC of 0.68 and a more accurate subsequent estimation of absorption efficiencies. The mean winter WS_BrC and MeS_BrC absorptions at 365 nm were 13.9 Mm-1 and 21.9 Mm-1, respectively, suggesting an important fraction of water-insoluble OA. Mean winter WS_BrC and MeS_BrC absorptions were over 10 times those observed in summer. MeS_OC was more absorptive than WSOC in winter (mean mass absorption efficiencies - MAE365: 1.81 vs 1.15 m2 gC-1) and especially in summer (MAE: 1.12 vs 0.27 m2 gC-1) due to photo-dissociation and volatilization of BrC chromophores. The winter radiative forcing (RF) of WS_BrC and MeS_BrC relative to elemental carbon (EC) was estimated at 8.7 % and 16.7 %, respectively, in the 300-2500 nm band. However, those values increased to 48.5 % and 60.2 % at 300-400 nm, indicating that, under intense RWB, BrC forcing becomes comparable to that of soot. The results highlight the consideration of urban BrC emissions in radiative transfer models, as a considerable climate forcing factor.

Impact of peri-urban forest fires on air quality and aerosol optical and chemical properties: The case of the August 2021 wildfires in Athens, Greece.

Wildfires occurring near urban areas are known to have exceedingly detrimental impacts on the environment, air quality, economy and human health. In this framework, this study examines the effects of peri-urban forest fires on atmospheric chemical composition, and aerosol physical-optical properties in Athens, Greece, during August 2021. Satellite imagery and air mass trajectories showed advection of intense smoke plumes over Athens from three forest fires persisting for 10 days in the greater Athens area and in Central Greece (Euboea). During August 1-20, 2021, daily PM2.5 concentrations ranged from 8.9 to 78.7 µg m-3, and were associated with high OC levels (2.3-27.8 µg m-3), while BC and BCbb concentrations on smoke-impacted days were 2.6 µg m-3 and 1.0 µg m-3, respectively (2-3 times higher than August mean levels). During the peak of biomass burning (BB) smoke transport over Athens, daily-average scattering and absorption coefficients at short wavelengths maximized at 313 Mm-1 and 171 Mm-1, respectively. There was also a large impact of ambient BrC (brown carbon) absorption (60 Mm-1), while the OC/EC ratio exhibited characteristically low values (3-4), linked to flaming combustion (modified combustion efficiency of 0.97-0.99). The absorption Ångström exponent (1.38) and single scattering albedo (0.74) indicated highly absorbing BB aerosol, deviating from the normal summer patterns. BB-tracers like nssK+ displayed strong correlations with OC, EC and BC concentrations, as well as with scattering and absorption coefficients. However, forest fires drastically modified the levels of additional chemical species, with enhancements observed for Ca2+, NO3-, Cl-, and for organic aerosol (OA) components such as BBOA and less-oxidized oxygenated OA (LO-OOA). Since under climate change conditions, the Mediterranean is anticipated to experience a dramatic rise in the frequency and intensity of wildfires, the results highlight the necessity for prevention and mitigation policies to safeguard urban air quality.

Human health risk assessment for toxic elements in the extreme ambient dust conditions observed in Sistan, Iran.

This study evaluates the bioaccessibility and health risks related to heavy metals (Cd, Cr, Co, Cu, Mn, Ni, Pb, Zn and metalloid As) in airborne dust samples (TSP and PM2.5) in Zabol, Iran during the summer dust period, when peak concentration levels of PM are typically observed. High bioaccessibilities of carcinogenic metals in PM2.5 (i.e. 53.3%, 48.6% and 47.6% for Ni, Cr and As, respectively) were calculated. The carcinogenic and non-carcinogenic health risks were assessed for three exposure pathways (inhalation, ingestion and dermal contact), separately for children and adults. Non-carcinogenic inhalation risks were very high (Hazard Index: HI > 1) both for children and adults, while the carcinogenic risks were above the upper acceptable threshold of 10-4 for adults and marginally close (5.0-8.4 × 10-5) for children. High carcinogenic risks (>10-4) were found for the ingestion pathway both for children and adults, while HI values > 1 (8.2) were estimated for children. Carcinogenic and non-carcinogenic risk estimates for dermal contact were also above the limits considered acceptable, except for the carcinogenic risk for children (7.6 × 10-5). Higher non-carcinogenic and carcinogenic risks (integrated for all elements) were associated with the inhalation pathway in adults and children with the exception of carcinogenic risk for children, where the ingestion route remains the most important, while As was linked with the highest risks for nearly all exposure pathways. A comparative evaluation shows that health risks related with toxic elements in airborne particles in Sistan are among the highest reported in the world.

Identification of key aerosol types and mixing states in the central Indian Himalayas during the GVAX campaign: the role of particle size in aerosol classification.

Studies in aerosol properties, types and sources in the Himalayas are important for atmospheric and climatic issues due to high aerosol loading in the neighboring plains. This study uses in situ measurements of aerosol optical and microphysical properties obtained during the Ganges Valley Aerosol eXperiment (GVAX) at Nainital, India over the period June 2011-March 2012, aiming to identify key aerosol types and mixing states for two particle sizes (PM1 and PM10). Using a classification matrix based on SAE vs. AAE thresholds (scattering vs. absorption Ångström exponents, respectively), seven aerosol types are identified, which are highly dependent on particle size. An aerosol type named "large/BC mix" dominates in both PM1 (45.4%) and PM10 (46.9%) mass, characterized by aged BC mixed with other aerosols, indicating a wide range of particle sizes and mixing states. Small particles with low spectral dependence of the absorption (AAE < 1) account for 31.6% and BC-dominated aerosols for 14.8% in PM1, while in PM10, a large fraction (39%) corresponds to "large/low-absorbing" aerosols and only 3.9% is characterized as "BC-dominated". The remaining types consist of mixtures of dust and local emissions from biofuel burning and display very small fractions. The main optical properties e.g. spectral scattering, absorption, single scattering albedo, activation ratio, as well as seasonality and dependence on wind speed and direction of identified types are examined, revealing a large influence of air masses originating from the Indo-Gangetic Plains. This indicates that aerosols over the central Himalayas are mostly composed by mixtures of processed and transported polluted plumes from the plains. This is the first study that identifies key aerosol populations in the central Indian Himalayas based on in situ measurements and the results are highly important for aerosol-type inventories, chemical transport models and reducing the uncertainty in aerosol radiative forcing over the third pole.

Apportionment of black and brown carbon spectral absorption sources in the urban environment of Athens, Greece, during winter.

This study examines the spectral properties and source characteristics of absorbing aerosols (BC: Black Carbon; BrC: Brown Carbon, based on aethalometer measurements) in the urban background of Athens during December 2016-February 2017. Using common assumptions regarding the spectral dependence of absorption due to BC (AAEBC = 1) and biomass burning (AAEbb = 2), and calculating an optimal AAEff value for the dataset (1.18), the total spectral absorption was decomposed into five components, corresponding to absorption of BC and BrC from fossil-fuel (ff) combustion and biomass burning (bb), and to secondary BrC estimated using the BC-tracer minimum R-squared (MRS) method. Substantial differences in the contribution of various components to the total absorption were found between day and night, due to differences in emissions and meteorological dynamics, while BrC and biomass burning aerosols presented higher contributions at shorter wavelengths. At 370 nm, the absorption due to BCff contributed 36.3% on average, exhibiting a higher fraction (58.1%) during daytime, while the mean BCbb absorption was estimated at 18.4%. The mean absorption contributions due to BrCff, BrCbb and BrCsec were 6.7%, 32.3% and 4.9%, respectively. The AbsBCff,370 component maximized during the morning traffic hours and was strongly correlated with NOx (R2 = 0.76) and CO (R2 = 0.77), while a similar behavior was seen for the AbsBrCff,370 component. AbsBCbb and AbsBrCbb levels escalated during nighttime and were highly associated with nss-K+ and with the organic aerosol (OA) components related to fresh and fast-oxidized biomass burning (BBOA and SV-OOA) as obtained from ACSM measurements. Multiple linear regression was used to attribute BrC absorption to five OA components and to determine their absorption contributions and efficiencies, revealing maximum contributions of BBOA (33%) and SV-OOA (21%). Sensitivity analysis was performed in view of the methodological uncertainties and supported the reliability of the results, which can have important implications for radiative transfer models.

Chemical characterization, sources and potential health risk of PM2.5 and PM1 pollution across the Greater Athens Area.

With the principal aim to assess the typical Mediterranean profile of the PM2.5 and PM1 pollution, three intensive monitoring campaigns took place simultaneously within different types of environment across an urban location of the basin. Focusing on the PM components with numerous anthropogenic sources and increased potential health risk, the samples were chemically analyzed for 20 p.m.-bound Polycyclic Aromatic Hydrocarbons (PAHs). Carbonaceous and ionic constituents were quantified as well. In order to uncover the spatiotemporal variation of the PM profile the key sources were identified, the seasonal effects and the role of the prevailing mesoscale atmospheric circulation were evaluated and most importantly the potential health risk was estimated. In general, the pollution status of the basin was the result of a complex interaction between the local and external input with Particulate Organic Matter (POM) and Secondary Inorganic Aerosols (SIA) being the main aerosols' components. PM1 was a better indicator of the anthropogenic emissions while according to the results of factor analysis the co-existence of various combustion sources was determinant. Chemically, the maxima of the ΣPAHs, the differentiation of their structure in accordance with their molecular weight and the distribution of the individual compounds confirmed the significance of the emission sources. Similarly, the estimated carcinogenicity/mutagenicity was emission-dependent with the maximum contribution coming from B[a]P, IndP, B[ghi]Per, B[e]P and B[b]F. Seasonally, the highest potential health risk of the PAHs' mixture was recorded during the cold season while meteorologically, it was mostly associated with the south flow.

Long-term brown carbon spectral characteristics in a Mediterranean city (Athens).

This study analyses 4-years of continuous 7-λ Aethalometer (AE-33) measurements in an urban-background environment of Athens, to resolve the spectral absorption coefficients (babs) for black carbon (BC) and brown carbon (BrC). An important BrC contribution (23.7 ± 11.6%) to the total babs at 370 nm is estimated for the period May 2015-April 2019, characterized by a remarkable seasonality with winter maximum (33.5 ± 13.6%) and summer minimum (18.5 ± 8.1%), while at longer wavelengths the BrC contribution is significantly reduced (6.8 ± 3.6% at 660 nm). The wavelength dependence of the total babs gives an annual-mean AAE370-880 of 1.31, with higher values in winter night-time. The BrC absorption and its contribution to babs presents a large increase reaching up to 39.1 ± 13.6% during winter nights (370 nm), suggesting residential wood burning (RWB) emissions as a dominant source for BrC. This is supported by strong correlations of the BrC absorption with OC, EC, the fragment ion m/z 60 derived from ACSM and PMF-analyzed organic fractions related to biomass burning (e.g. BBOA). In contrast, BrC absorption decreases significantly during daytime as well as in the warm period, reaching to a minimum during the early-afternoon hours in all seasons due to photo-chemical degradation. Estimated secondary BrC absorption is practically evident only during winter night-time, implying the fast oxidation of BrC species from RWB emissions. Changes in mixing-layer height do not significantly affect the BrC absorption in winter, while they play a major role in summer.

Indoor and outdoor PM mass and number concentrations at schools in the Athens area.

Simultaneous indoor and outdoor PM10 and PM2.5 concentration measurements were conducted in seven primary schools in the Athens area. Both gravimetric samplers and continuous monitors were used. Filters were subsequently analyzed for anion species. Moreover ultrafine particles number concentration was monitored continuously indoors and outdoors. Mean 8-hr PM10 concentration was measured equal to 229 +/- 182 microg/m3 indoors and 166 +/- 133 microg/m3 outdoors. The respective PM2.5 concentrations were 82 +/- 56 microg/m3 indoors and 56 +/- 26 microg/m3 outdoors. Ultrafine particles 8-h mean number concentration was measured equal to 24,000 +/- 17,900 particles/cm3 indoors and 32,000 +/- 14,200 particles/cm3 outdoors. PM10 outdoor concentrations exhibited a greater spatial variability than the corresponding PM2.5 ones. I/O ratios were close or above 1.00 for PM10 and PM2.5 and smaller than 1.00 for ultrafine particles. Very high I/O ratios were observed when intense activities took place. The initial results of the chemical analysis showed that SO4(-2) accounts for the 6.6 +/- 3.5% of the PM10 and NO3(1) for the 3.1 +/- 1.4%.The corresponding results for PM2.5 are 12.0 +/- 7.7% for SO4(-2) and 3.1 +/- 1.9% for NO3-. PM2.5 SO4(-2) indoor concentrations were highly correlated with outdoor ones and the regression line had the largest slope and a very low intercept, indicative of no indoor sources of fine particulate SO4(-2). The results of the statistical analysis of indoor and outdoor concentration data support the use of SO4(-2) as a proper surrogate for indoor PM of outdoor origin.

Past, Present and Future Atmospheric Nitrogen Deposition.

Reactive nitrogen emissions into the atmosphere are increasing due to human activities, affecting nitrogen deposition to the surface and impacting the productivity of terrestrial and marine ecosystems. An atmospheric chemistry-transport model (TM4-ECPL) is here used to calculate the global distribution of total nitrogen deposition, accounting for the first time for both its inorganic and organic fractions in gaseous and particulate phases, and past and projected changes due to anthropogenic activities. The anthropogenic and biomass burning ACCMIP historical and RCP6.0 and RCP8.5 emissions scenarios are used. Accounting for organic nitrogen (ON) primary emissions, the present-day global nitrogen atmospheric source is about 60% anthropogenic, while total N deposition increases by about 20% relative to simulations without ON primary emissions. About 20-25% of total deposited N is ON. About 10% of the emitted nitrogen oxides are deposited as ON instead of inorganic nitrogen (IN) as is considered in most global models. Almost a 3-fold increase over land (2-fold over the ocean) has been calculated for soluble N deposition due to human activities from 1850 to present. The investigated projections indicate significant changes in the regional distribution of N deposition and chemical composition, with reduced compounds gaining importance relative to oxidized ones, but very small changes in the global total flux. Sensitivity simulations quantify uncertainties due to the investigated model parameterizations of IN partitioning onto aerosols and of N chemically fixed on organics to be within 10% for the total soluble N deposition and between 25-35% for the dissolved ON deposition. Larger uncertainties are associated with N emissions.

Sources of atmospheric aerosol from long-term measurements (5 years) of chemical composition in Athens, Greece.

To identify the sources of aerosols in Greater Athens Area (GAA), a total of 1510 daily samples of fine (PM 2.5) and coarse (PM 10-2,5) aerosols were collected at a suburban site (Penteli), during a five year period (May 2008-April 2013) corresponding to the period before and during the financial crisis. In addition, aerosol sampling was also conducted in parallel at an urban site (Thissio), during specific, short-term campaigns during all seasons. In all these samples mass and chemical composition measurements were performed, the latest only at the fine fraction. Particulate organic matter (POM) and ionic masses (IM) are the main contributors of aerosol mass, equally contributing by accounting for about 24% of the fine aerosol mass. In the IM, nss-SO4(-2) is the prevailing specie followed by NO3(-) and NH4(+) and shows a decreasing trend during the 2008-2013 period similar to that observed for PM masses. The contribution of water in fine aerosol is equally significant (21 ± 2%), while during dust transport, the contribution of dust increases from 7 ± 2% to 31 ± 9%. Source apportionment (PCA and PMF) and mass closure exercises identified the presence of six sources of fine aerosols: secondary photochemistry, primary combustion, soil, biomass burning, sea salt and traffic. Finally, from winter 2012 to winter 2013 the contribution of POM to the urban aerosol mass is increased by almost 30%, reflecting the impact of wood combustion (dominant fuel for domestic heating) to air quality in Athens, which massively started in winter 2013.

PM10 and PM2.5 composition over the Central Black Sea: origin and seasonal variability.

Daily PM10 and PM2.5 samples were collected between April 2009 and July 2010 at a rural site (Sinop) situated on the coast of the Central Black Sea. The concentrations of PM10 and PM2.5 were 23.2 ± 16.7 and 9.8 ± 6.9 µg m(-3), respectively. Coarse and fine filters were analyzed for Cl(-), NO3(-), SO4(2-), C2O4(2-), PO4(3-), Na(+), NH4(+), K(+), Mg(2+), and Ca(2+) by using ion chromatography. Elemental and organic carbon content in bulk quartz filters were also analyzed. The highest PM2.5 contribution to PM10 was found in summer with a value of 0.54 due to enhanced secondary aerosols in relation to photochemistry. Cl(-), Na(+), and Mg(2+) illustrated their higher concentrations and variability during winter. Chlorine depletion was chiefly attributed to nitrate. Higher nssCa(2+) concentrations were ascribed to episodic mineral dust intrusions from North Africa into the region. Crustal material (31%) and sea salt (13%) were found to be accounted for the majority of the PM10. The ionic mass (IM), particulate organic matter (POM), and elemental carbon (EC) explained 13, 20, and 3% of the PM10 mass, correspondingly. The IM, POM, and EC dominated the PM2.5 (~74%) mass. Regarding EU legislation, the exceeded PM2.5 values were found to be associated with secondary aerosols, with a particular dominance of POM. For the exceeded PM10 values, six of the events were dominated by dust while two and four of these exceedances were caused by sea salt and mix events, respectively.

Airborne mineral components and trace metals in Paris region: spatial and temporal variability.

A variety of mineral components (Al, Fe) and trace metals (V, Cr, Mn, Ni, Cu, Zn, Cd, Pb) were simultaneously measured in PM2.5 and PM10 fractions at three different locations (traffic, urban, and suburban) in the Greater Paris Area (GPA) on a daily basis throughout a year. Mineral species and trace metal levels measured in both fractions are in agreement with those reported in the literature and below the thresholds defined by the European guidelines for toxic metals (Cd, Ni, Pb). Size distribution between PM2.5 and PM10 fractions revealed that mineral components prevail in the coarse mode, while trace metals are mainly confined in the fine one. Enrichment factor analysis, statistical analysis, and seasonal variability suggest that elements such as Mn, Cr, Zn, Fe, and Cu are attributed to traffic, V and Ni to oil combustion while Cd and Pb to industrial activities with regional origin. Meteorological parameters such as rain, boundary layer height (BLH), and air mass origin were found to significantly influence element concentrations. Periods with high frequency of northern and eastern air masses (from high populated and industrialized areas) are characterized by high metal concentrations. Finally, inner city and traffic emissions were also evaluated in PM2.5 fraction. Significant contributions (>50 %) were measured in the traffic site for Mn, Fe, Cr, Zn, and Cu, confirming that vehicle emissions contribute significantly to their levels, while in the urban site, the lower contributions (18 to 33 %) for all measured metals highlight the influence of regional sources on their levels.

Physical and chemical processes of air masses in the Aegean Sea during Etesians: Aegean-GAME airborne campaign.

High-resolution measurements of gas and aerosols' chemical composition along with meteorological and turbulence parameters were performed over the Aegean Sea (AS) during an Etesian outbreak in the framework of the Aegean-GAME airborne campaign. This study focuses on two distinct Etesian patterns, with similarities inside the Marine Atmospheric Boundary Layer (MABL) and differences at higher levels. Under long-range transport and subsidence the pollution load is enhanced (by 17% for CO, 11% for O3, 28% for sulfate, 62% for organic mass, 47% for elemental carbon), compared to the pattern with a weaker synoptic system. Sea surface temperature (SST) was a critical parameter for the MABL structure, turbulent fluxes and pollutants' distribution at lower levels. The MABL height was below 500 m asl over the eastern AS (favoring higher accumulation), and deeper over the western AS. The most abundant components of total PM1 were sulfate (40-50%) and organics (30-45%). Higher average concentrations measured over the eastern AS (131 ± 76 ppbv for CO, 62.5 ± 4.1 ppbv for O3, 5.0 ± 1.1 µg m(-3) for sulfate, 4.7 ± 0.9 µg m(-3) for organic mass and 0.5 ± 0.2 µg m(-3) for elemental carbon). Under the weaker synoptic system, cleaner but more acidic air masses prevailed over the eastern part, while distinct aerosol layers of different signature were observed over the western part. The Aitken and accumulation modes contributed equally during the long-range transport, while the Aitken modes dominated during local or medium range transport.

Influenza: recommendations for vaccination and treatment.

Influenza kills millions of people each year and has the potential to kill even more if proper vaccination and treatment protocols are not followed. This review provides the Louisiana State Office of Public Health and the Centers for Disease Control recommendations for vaccination and treatment of influenza.

Assessment of PM2.5 and PM1 chemical profile in a multiple-impacted Mediterranean urban area: origin, sources and meteorological dependence.

Airborne particulate matter in the PM2.5 and PM1 size ranges has been sampled at three sites within the Mediterranean urban area of the Athens Basin, representing background, roadside-industrialized and coastal background locations. With the principal aim to identify the sources and discriminate the contribution of the regional input versus the local one, simultaneous chemical characterization with respect to carbonaceous and ionic species was also carried out on the collected samples. In general, the average recorded values were within the Mediterranean concentration range. The constant prevalence of the ionic mass (52%-79%) over one of the carbonaceous, being combined with the occurrence of its maximum rates at the coastal background environment (74%-79% and 73%-77% for PM2.5 and PM1, respectively) leads to the hypothesis that the fine PM pollution in the basin, especially for the remote locations, is evidently governed by the external intrusion. Even at the polluted atmosphere of the roadside-industrialized environment, the PM mass was regionally originated, with the corresponding input reaching up to 87% (northward flow). Applying factor analysis on the PM2.5 database it came obvious that the sources which were responsible for the configured PM burden were not fully differentiated not only between the different types of environment but also between the exceedances and the clean air events. The contribution of the secondary, marine and combustion processes was constant at all the stations of the network, while a continuous input of crustal particles characterized both the roadside-industrialized and the coastal atmosphere. Finally, the episodic values show a general common signal of secondary mixed ΡΜ emissions, high influence of both regional and local pollution spikes, confirming the earlier findings for the significance of transportation.

Carbonaceous and ionic compositional patterns of fine particles over an urban Mediterranean area.

A carefully designed experimental study based on the monitoring of fine airborne particles, was carried out at three different locations (suburban background, traffic-industrial, coastal background) of an urban Mediterranean area, the Athens Basin. Understanding of the PM(2.5) and PM(1) nature has an important policy implication. In total, five hundred and nineteen samples were chemically analyzed with respect to carbonaceous (organic/elemental carbon) and ionic (NH(4)(+), K(+), Mg(2+), Ca(2+), NO(3)(-), Cl(-), SO(4)(2-)) species. The dataset consists one of the very few in the Mediterranean which simultaneously deals with the carbonaceous and ionic components of fine aerosol fractions, especially for PM(1). Daily PM(2.5) averages often exceeded the E.U. limit values, with their mass being mainly composed of PM(1). The most important constituents of secondary particles were SO(4)(2-) and organic carbon, with both accounting for 56.4%-64.3% and 60.5%-62.3% of the total PM(2.5) and PM(1) mass, respectively. Regional sources, marine/crustal elements, combustion sources and traffic were indicated by factor analysis as the greatest contributors to the mass of both PM(2.5) and PM(1) fractions, accounting for 85.3% and 83.6%, respectively of the total variance in the system. It is worthy to note, the key role of the prevailing atmospheric conditions to the configuration of the obtained picture of the particulate pollution.

Aerosol chemical composition over Istanbul.

This study examines the chemical composition of aerosols over the Greater Istanbul Area. To achieve this 325 (PM(10)) aerosol samples were collected over Bosphorus from November 2007 to June 2009 and were analysed for the main ions, trace metals, water-soluble organic carbon (WSOC), organic (OC) and elemental carbon (EC). PM(10) levels were found to be in good agreement with those measured by the Istanbul Municipality air quality network, indicating that the sampling site is representative of the Greater Istanbul Area. The main ions measured in the PM(10) samples were Na(+), Ca(2+) and non-sea-salt sulphates (nss-SO(4)(2-)). On average, 31% of Ca(2+) was found to be associated with carbonates. Trace elements related to human activities (as Pb, V, Cd and Ni) obtained peak values during winter due to domestic heating, whereas natural origin elements like Al, Fe and Mn peaked during the spring period due to dust transport from Northern Africa. Organic carbon was found to be mostly primary and elemental carbon was strongly linked to fuel oil combustion and traffic. Both OC and EC concentrations increased during winter due to domestic heating, while the higher WSOC to OC ratio during summer can be mostly attributed to the presence of secondary, oxidised and more soluble organics. Factor analysis identified six components/sources for aerosol species in PM(10), namely traffic/industrial, crustal, sea-salt, fuel-oil combustion, secondary and ammonium sulfate.

CH4 and CO emissions from rice straw burning in South East Asia.

Atmospheric samples collected during rice straw burning at four different locations in Viet-Nam during the dry (March 1992, February 1993) and wet season (August 1992) were analysed for CO2, CO, and CH4. The emission ratios relative to CO2 for CO and CH4 for rice straw burning during the dry season were comparable to those observed on samples collected during burning of savanna in Africa or forest in the USA. During the wet season, however the emission ratios for CO and CH4 relative to CO2 were 3 to 10 times higher. With these emission ratios and estimates of rice production from Southeastern Asia, we estimated that burning of rice straw emits annually about 2.2 Tmol of CO (26 TgC) and 0.2 Tmol of CH4 (2.4 TgC) to the atmosphere. Taking into account these new results, CO and CH4 fluxes from biomass burning could be reevaluated by 5-21% and 5-24%, respectively, in respect with previous estimates of these gas emissions from all biomass burning activities.