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.
•Severe concentration levels of As and heavy metals in airborne dust in Zabol.•Large bioaccessibility fractions (∼50%) for carcinogenic elements Ni, Cr, Cd, As.•Carcinogenic and non-carcinogenic risks was very higher than acceptable thresholds.•The inhalation pathway, and As, Cr exposures are associated with the highest risks.
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•Pronounced seasonal variation in aerosol absorption in Athens over a 4-year period.•Significant BrC contribution (23.7%) to the total aerosol absorption at 370 nm.•Strong winter-time ...correlations between BrC and BB-related organic aerosols.•The BrCsec absorption is related to residential wood burning during winter nights.
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.
Elemental and organic carbon (EC and OC) hourly concentrations were measured continuously, at an urban location in central Athens, Greece, for an 8-month period (January–August). Average ...concentrations of 2.2μgCm−3 and 6.8μgCm−3 were observed, for EC and OC, respectively. The combined contribution of carbonaceous compounds (EC plus organic matter) to PM10 was calculated at 26%. The seasonal variability of EC was limited, while OC mean concentrations were significantly higher (by 23%), during the warm months (May–August). The weekly variation followed a different pattern, with the weekend decrease of EC levels (25%) being more pronounced than of OC (14%). EC produced a bimodal diurnal cycle, with the morning rush hour traffic mode prevailing. The OC mean circadian variation displayed those peaks as well. However, midday-to-afternoon presence of secondary organic aerosol (SOA) was strongly indicated. The conditional probability function was used to assess the impact of wind direction. High EC, OC levels were linked to southern flows, which during summer are mainly related to the appearance of sea breeze circulation. The temporal variation of EC, OC and their correlation patterns with primary and secondary gaseous pollutants, suggested that, although primary emissions affected both fractions, SOA formation is an important factor to be accounted for, especially during the photochemical season. Secondary organic carbon was estimated using the EC tracer method and orthogonal regression on OC, EC hourly concentration data. The average contributions of secondary organic carbon (SOC) to OC were calculated at 20.9% for the cold period and 30.3% for the warm period. Maximum values of 58% and 91% were estimated for daily and hourly contributions, respectively. The SOC diurnal variations suggested photochemical formation throughout the year, intensified during summer months, with the correlation coefficient between SOC and the sum of oxidants (NO2+O3) reaching up to 0.84.
► Long term measurements of EC–OC, with a high time resolution, are reported for the first time in Athens. ► Mean OC concentrations ranked in the upper echelon of levels observed in Europe. ► Seasonal and diurnal patterns indicate the importance of SOA. ► Hourly variations of SOA are estimated for the first time in Athens. ► The conservative average estimate for the secondary component of OC, at an urban location, is 25%.
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.
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•New approach to apportion BC - BrC absorption from biomass and fossil fuel burning•Combination of “Brown Carbon” and “Aethalometer” models in winter data in Athens•Biomass burning is the dominant nighttime BrC absorption source at 370–660 nm.•In daytime, traffic controls BC absorption and also affects near-UV BrC absorption.•Regressing BrC on ACSM PMF-resolved OA components provides their MAE and AAE values.
Coarse particles of aerodynamic diameter between 2.5 and 10 μm (PMc) are produced by a range of natural (windblown dust and sea sprays) and anthropogenic processes (non-exhaust vehicle emissions, ...industrial, agriculture, construction and quarrying activities). Although current ambient air quality regulations focus on PM2.5 and PM10, coarse particles are of interest from a public health point of view as they have been associated with certain mortality and morbidity outcomes.
In this paper, an analysis of coarse particle levels in three European capitals (London, Madrid and Athens) is presented and discussed. For all three cities we analysed data from both traffic and urban background monitoring sites. The results showed that the levels of coarse particles present significant seasonal, weekly and daily variability. Their wind driven and non-wind driven resuspension as well as their roadside increment due to traffic were estimated. Both the local meteorological conditions and the air mass history indicating long-range atmospheric transport of particles of natural origin are significant parameters that influence the levels of coarse particles in the three cities especially during episodic events.
► Coarse particle levels in Athens, Madrid and London. ► Wind driven and non-wind driven resuspension of coarse particles. ► Long-range atmospheric transport and roadside increment of coarse particles.
In the present paper, 1-year PM10 and PM2.5 data from roadside and urban background monitoring stations in Athens (Greece), Madrid (Spain) and London (UK) are analysed in relation to other air ...pollutants (NO, NO2, NOx, CO, O3 and SO2) and several meteorological parameters (wind velocity, temperature, relative humidity, precipitation, solar radiation and atmospheric pressure), in order to investigate the sources and factors affecting particulate pollution in large European cities. Principal component and regression analyses are therefore used to quantify the contribution of both combustion and non-combustion sources to the PM10 and PM2.5 levels observed. The analysis reveals that the EU legislated PM10 and PM2.5 limit values are frequently breached, forming a potential public health hazard in the areas studied. The seasonal variability patterns of particulates varies among cities and sites, with Athens and Madrid presenting higher PM10 concentrations during the warm period and suggesting the larger relative contribution of secondary and natural particles during hot and dry days. It is estimated that the contribution of non-combustion sources varies substantially among cities, sites and seasons and ranges between 38–67% and 40–62% in London, 26–50% and 20–62% in Athens, and 31–58% and 33–68% in Madrid, for both PM10 and PM2.5. Higher contributions from non-combustion sources are found at urban background sites in all three cities, whereas in the traffic sites the seasonal differences are smaller. In addition, the non-combustion fraction of both particle metrics is higher during the warm season at all sites. On the whole, the analysis provides evidence of the substantial impact of non-combustion sources on local air quality in all three cities. While vehicular exhaust emissions carry a large part of the risk posed on human health by particle exposure, it is most likely that mitigation measures designed for their reduction will have a major effect only at traffic sites and additional measures will be necessary for the control of background levels. However, efforts in mitigation strategies should always focus on optimal health effects.
•Sources and factors affecting PM are investigated in Athens, London and Madrid.•EU PM limit values are frequently breached forming a potential public health hazard.•Contribution of secondary/natural PM in summertime is higher in Athens and Madrid.•Contribution of non-combustion sources varies among cities, sites and seasons.•Non-combustion fraction of both PM metrics is higher during summer at all sites.
Air quality degradation events in the urban environment are often attributed to anthropogenic aerosol sources related to combustion of liquid or solid fuels in various activities. The effects of ...massive cooking emissions during Greek nationwide traditional festivities were investigated by a combined characterization of particulate matter (PM) levels and organic aerosol (OA) sources. Focus was centered on periods around two major festivities, namely “Fat Thursday” and Easter Sunday along six different years. OA sources were apportioned through Positive Matrix Factorization (PMF) on Aerosol Chemical Speciation Monitor (ACSM) mass spectra, while the spatial characteristics of the episodes were assessed through a low-cost, sensor-based PM2.5 monitoring network operating in Athens and other Greek cities. Contrasts were examined by considering a 15-day period around each event, while the effect of the 2020–2021 mobility restrictions, related to COVID-19, was also assessed. An episode-specific cooking organic aerosol (COA) spectral profile was delineated, and can be considered as a reference for ambient COA from meat grilling. Severe pollution episodes that affected the entire Athens basin were recorded, with PM2.5 concentrations exceeding 300 μg m−3 on occasions. COA contributions dominated primary organic aerosol (POA) and made up almost half of OA concentrations. During “Fat Thursday” COA concentrations and contributions peaked during night-time (23.2 μg m−3 and 46 %, respectively) while for Easter Sunday COA maxima were recorded in the early afternoon (27.4 μg m−3 and 39 %). Analyzing a full-year OA source dataset, revealed a pronounced recreational cooking pattern in central Athens, with COA concentrations rising towards the weekend, reflecting the impact of the food service sector. In view of the upcoming review of the EU air quality directive, foreseeing stricter annual PM2.5 limits as well as 24-h limit values and related alerts, the mitigation of cooking emissions appears as a potent instrument for achieving tangible air quality benefits.
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•Severe air quality degradation documented during festivities involving meat grilling•During meat grilling events COA contributions to organic aerosol mass nearly doubled•Urban extent of cooking aerosols spatially expands during meat grilling events.•COA temporal variability under normal conditions follows a recreational pattern.•Meat charbroiling ambient COA spectrum extracted from extended “Fat Thursday” measurements
The present study analyzes PM₁₀ concentration data collected by the Greek air quality monitoring network at 8 sites over the Greater Athens Area, for the period of 2001-2004. The primary objectives ...were to assess the degree of compliance with the EU-legislated air quality standard for PM₁₀ and also provide an overall statistical examination of the factors controlling the seasonal and spatial variation of concentrations, over the wider urban agglomeration. Daily concentrations, averaged over the whole study period, ranged between 32.3 and 60.9 μg m-³. The four-year average concentration of PM₁₀ at five sites exceeded the annual limit value of 40 μg m-³, while most of the sites surpassed the allowed percentage of exceedances of the daily limit value (50 μg m-³), for each of the four years. The seasonal variation of PM₁₀ levels was not found to be uniform across the eight sites, with average cold-period concentrations being higher at four of them and warm period concentrations being significantly higher at three sites, which also displayed recurring annual variation of monthly concentrations. Concentration levels displayed moderate spatial heterogeneity. Nevertheless significant inter-site correlations were observed (ranging between 0.55 and 085). The determination of the spatial correlation levels relied mainly on site types rather than on inter-site distances. Monitoring sites were classified accordingly using cluster analysis in two groups presenting distinct spatiotemporal variation and affected by different particle formation processes. The group including urban sites was mainly affected by primary, combustion-related processes and especially vehicular traffic, as it was also deduced through the examination of the diurnal distribution of particulate levels and through factor analysis. On the contrary, suburban background sites seemed more affected by particle transport from more polluted neighboring areas and secondary particle formation through gaseous precursors, both processes aided from favoring meteorological conditions. The association of the PM₁₀ levels with backwards trajectories was also examined, in an attempt to account for the possible long range transport of particles in Athens. It was found that a notable part of area-wide episodic events could be attributed to trans-boundary transport of particles, with the origins of some severe dust outbreaks traced back to the Sahara desert and the Western Mediterranean.
ObjectivesTo assess how biomarkers indicating central nervous system insult (neurobiomarkers) vary in peripheral blood with exertional-heat stress from prolonged endurance ...exercise.DesignObservational study of changes in neuron specific enolase (NSE), S100 calcium-binding protein B (S100β), Glial Fibrillary Acid Protein (GFAP) and Ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1) at Brighton Marathon 2022.MethodsIn 38 marathoners with in-race core temperature (Tc) monitoring, exposure (High, Intermediate or Low) was classified by cumulative hyperthermia – calculated as area under curve of Time × Tc > 38 °C – and also by running duration (finishing time). Blood was sampled for neurobiomarkers, cortisol and fluid-regulatory stress surrogates, including copeptin and creatinine (at rested baseline; within 30 min of finishing; and at 24 h).ResultsFinishing in 236 ± 40 min, runners showed stable GFAP and UCH-L1 across the marathon and next-day. Significant (P < 0.05) increases from baseline were shown post-marathon and at 24 h for S100β (8.52 3.65, 22.95 vs 39.0 26.48, 52.33 vs 80.3 49.1, 99.7 ng·L−1) and post-marathon only for NSE (3.73 3.30, 4.32 vs 4.85 4.45, 5.80 μg·L−1, P < 0.0001). Whilst differential response to hyperthermia was observed for cortisol, copeptin and creatinine, neurobiomarker responses did not vary. Post-marathon, only NSE differed by exercise duration (High vs Low, 5.81 ± 1.77 vs. 4.69 ± 0.73 μg·L−1, adjusted P = 0.0358).ConclusionsSuccessful marathon performance did not associate with evidence for substantial neuronal insult. To account for variation in neurobiomarkers with prolonged endurance exercise, factors additional to hyperthermia, such as exercise duration and intensity, should be further investigated.
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