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The relative impact of non-exhaust sources (i.e. road dust, tire wear, road wear and brake wear particles) on urban air quality is increasing. Among them, road dust resuspension has generally the highest impact on PM concentrations but its spatio-temporal variability has been rarely studied and modeled. Some recent studies attempted to observe and describe the time-variability but, as it is driven by traffic and meteorology, uncertainty remains on the seasonality of emissions. The knowledge gap on spatial variability is much wider, as several factors have been pointed out as responsible for road dust build-up: pavement characteristics, traffic intensity and speed, fleet composition, proximity to traffic lights, but also the presence of external sources. However, no parameterization is available as a function of these variables. We investigated mobile road dust smaller than 10 μm (MF10) in two cities with different climatic and traffic conditions (Barcelona and Turin), to explore MF10 seasonal variability and the relationship between MF10 and site characteristics (pavement macrotexture, traffic intensity and proximity to braking zone). Moreover, we provide the first estimates of emission factors in the Po Valley both in summer and winter conditions. Our results showed a good inverse relationship between MF10 and macro-texture, traffic intensity and distance from the nearest braking zone. We also found a clear seasonal effect of road dust emissions, with higher emission in summer, likely due to the lower pavement moisture. These results allowed building a simple empirical mode, predicting maximal dust loadings and, consequently, emission potential, based on the aforementioned data. This model will need to be scaled for meteorological effect, using methods accounting for weather and pavement moisture. This can significantly improve bottom-up emission inventory for spatial allocation of emissions and air quality management, to select those roads with higher emissions for mitigation measures. [ABSTRACT FROM AUTHOR]

Abstract: Previous studies reported significant variability of air pollutants across Europe with the lowest concentrations generally found in Northern Europe and the highest in Southern European countries. Within the MED-PARTICLES project the spatial and temporal variations of long-term PM and gaseous pollutants data were investigated in traffic and urban background sites across Southern Europe. The highest PM levels were observed in Greece and Italy (Athens, Thessaloniki, Turin and Rome) while all traffic sites showed high NO2 levels, frequently exceeding the established limit value. High PM2.5/PM10 ratios were calculated indicating that fine particles comprise a large fraction of PM10, with the highest values found in the urban background sites. It seems that although in traffic sites the concentrations of both PM2.5 and PM10 are significantly higher than those registered in urban background sites, the coarse fraction PM2.5–10 is more important at the traffic sites. This fact is probably due to the high levels of resuspended road dust in sites highly affected by traffic, a phenomenon particularly relevant for Mediterranean countries. The long-term trends of air pollutants revealed a significant decrease of the concentration levels for PM, SO2 and CO while for NO2 no clear trend or slightly increasing trends were observed. This reduction could be attributed to the effectiveness of abatement measures and strategies and also to meteorological conditions and to the economic crisis that affected Southern Europe. [Copyright &y& Elsevier]

Abstract: Simultaneous measurements of the PM concentration levels and chemical composition of atmospheric aerosols at a regional background (RB) and an urban background (UB) site, located in the same geographic region, allowed for the determination of their urban and regional contributions. In the specific case of the North-Western region of the Mediterranean the RB amount has been quantified in 18, 13 and 12 μg m−3 for PM10, PM2.5 and PM1, respectively, whereas the UB contribution reached 22, 13 and 8 μg m−3, respectively. The UB contributions in the Western Mediterranean are much higher than those observed in other European regions; especially concerning the coarse fraction. The high loads of road dust in the urban areas across the Mediterranean may account for these large differences. The urban contributions are extremely enriched in Ca, Fe, Sb, Sn, Cu, Zn, being the main tracers of the road dust, with concentrations up to 6–8 times higher than those at the RB. Elemental carbon and nitrate are mainly derived from direct vehicular emissions. Some industrial tracers (Mn, Pb, Bi) are also enriched in the urban area. The evaluation of the Cu/Sb, Cu/Zn, Cu/Cd and Cu/Pb ratios and the high enrichment of these trace elements versus the Upper Crustal Composition average values corroborates the importance of the road-traffic emissions in the study area, also influencing the RB. The supplementary results from a suburban site in the Balearic Islands and the evaluation of the V/Ni ratios evidence the strong signature of fuel-oil combustion processes, which is a general characteristic of the Mediterranean aerosols. [Copyright &y& Elsevier]

The origin of the daily exceedances of 50μg PM10m−3 (daily limit value or DLV of the EU air quality directive) and of an arbitrary daily value (DV) 35μg PM2. 5m−3 recorded in 2001–2003 in 13 regional background stations of the Iberian Peninsula were interpreted. This was carried out by means of back-trajectory analysis, available PM model outputs, satellite data and meteorological maps. This allows the detection of high PM episodes on a regional scale and the study of their seasonal and geographical variability. The number of exceedances of the PM10 DLV ranged in 2001–2003 from 6 to 41 depending on the monitoring site. For the selected PM2. 5DV, the range of daily exceedances was 0–10 in the study period. The majority of the PM10 (>70% in most stations) and PM2. 5 (17–55% in most stations) exceedances in regional background monitoring stations are caused by African dust outbreaks. These exceedances were less frequent in winter than in summer due to: (a) the frequent long range transport of dust in the warm seasons over Iberia, (b) the re-suspension associated with convective atmospheric dynamics, and (c) the relative low rainfall favouring re-suspension and high residence time of PM. Moreover, a regional contribution of secondary aerosols derived from the efficient photochemical transformation of gaseous precursors may coincide with African transport in summer. Episodes with lack of advective conditions caused 2–29% and 20–50% of the PM10 and PM2. 5 exceedances. These occurred mainly in summer due to poor renovation of air masses, increased convective re-suspension, dispersion of pollutants towards rural areas and regional re-circulation and aging of air masses which result in the proliferation of secondary inorganic species. Long-range transport of PM from continental Europe caused exceedances (9–40% and 18–38% of the PM10 and PM2. 5 exceedances, respectively), only in northern Iberia because, as the European air masses evolve towards the south, the pollutants suffer dispersion/dilution. Local exceedances are associated with the advection of the clean Atlantic air masses, which cannot increase PM levels to a great extent without the influence of a local source of PM. The proportion of local exceedances of PM10 and PM2. 5 ranged 6–33% and 17–40%, respectively. [Copyright &y& Elsevier]

Abstract: The majority of the Spanish urban population breathe air containing inhalable ambient airborne particles at average concentrations of 30–46μgm−3 (PM10) and 20–30μgm−3 (PM2.5). Even though the average weight of inhaled urban aerosol is commonly similar, however, there can be large chemical differences between the ambient dusts from different towns, including the more bioreactive elements such as some metals. In this context, we compare the source-apportioned trace metal content of airborne PM10 and PM2.5 collected daily over a 1-year period from six population centres in Spain: Barcelona, Alcobendas, Llodio, Huelva, Tarragona and Las Palmas de Gran Canaria. Total average trace metal (ΣTM) PM10 and PM2.5 contents vary by up to a factor of around 3, reaching a maximum of ΣTM10 811ngm−3 and ΣTM2.5 503ngm−3 at Llodio, an industrial but humid site with the lowest PM10 mass levels but high contamination by Zn, Pb, Mn, Sn, Ni and Cr. In contrast, pollution at Huelva, although another industrially influenced site, instead emphasises Cu and As, whereas Barcelona, where traffic emissions and resuspension contribute to some of the highest average PM10 levels in Spain, has unusually raised levels of Ti, V and Ba. Such variations in both daily and annual average PM bulk chemistry, particularly in potentially toxic trace metals concentrated in the finer aerosols (such as Cd, As, Pb, Hg and Ni), predict that PM health effects on resident populations from different towns are unlikely to be the same. [Copyright &y& Elsevier]

Abstract: A 12-month study of PM10 and gases in the industrial Spanish town of Puertollano reveals striking variations in pollutant concentrations. The normal daily pollution pattern is characterised by a daily double peak for NO x and CO and associated double trough for ozone (morning and evening), a midday atmospheric fumigation peak for SO2 and PM10 (1–2h later in winter), and a late morning through afternoon maximum for ozone (shorter and lower in winter). Superimposed upon this are: (1) seasonal variations, which accentuate the PM10 and SO2 mid-morning peaks in winter (when the peak occurs later than in summer), raise NO2, ozone and background particulate levels during the summer, and favour enhanced levels of NO during the winter; (2) local pollution spikes, particularly those associated with SO2 release from nearby industrial sources; (3) regional atmospheric stagnation episodes, which enhance concentrations of all pollutants and (4) intrusion of exotic pollutants, notably desert dust from North Africa. Given that air pollutants are known adversely to influence human health, understanding and predicting such diurnal variations in concentrations of inhalable pollutants is especially relevant to susceptible individuals such as asthmatics. [Copyright &y& Elsevier]

Abstract: The area of Castilla-La Mancha in central Spain is repeatedly visited by mineral dust incursions from the deserts of NW Africa. Such exotic atmospheric intrusions raise background PM10 levels, making urban areas much more likely to exceed daily limits of 50μgm−3 and become subject to fines under European environmental law. Data from a 3-year (2001–2003) study of hourly PM10 values demonstrate that average background dust levels in remote sites rise from 6–8μgm−3 when Atlantic-derived W/SW winds are blowing, to 24–7μgm−3 when African events take place. In four Castilla-La Mancha towns, numbers of exceedence days (ED: when PM10>50μgm−3) per year averaged 31 in Guadalajara (suburban site with annual daily PM10 average ADPM10=27μgm−3), 68 in Toledo (ADPM10=38μgm−3) and 139 in Albacete (ADPM10=47μgm−3; both urban sites), and 151 in Puertollano (industrial urban site with ADPM10=51μgm−3). Thirty-four percent of ED occurred during African dust incursions, and current law allows exclusion of such days from annual data (which also reduces the ADPM10 by 2–4μgm−3). Rather than simply excluding such days, a more scientifically satisfactory approach would be to allow subtraction of the estimated component of exotic background dust present daily at every urban monitoring station, and thus identify towns subject to high levels of locally derived anthropogenic PM10. Such an approach reduces ADPM10 values by the same amount as above (2–4μgm−3) if only African-derived PM10 values (as measured at remote background stations) are subtracted, although ΣED shows a relative increase. If, however, an attempt is made to estimate and subtract the total amount of exotic PM10 (i.e. not just African non-locally derived) at the four sites, this reduces the ADPM10 by 8–12μgm−3, and ΣED also drops significantly. Whichever approach is adopted, however, our data confirm that the legally allowable number of ED is far more strict than the annual limit value. This inconsistency will make it especially difficult for many southern European towns, with their abundant dry dust resuspension and regular incursions of African dust, to achieve PM exceedence targets in 2005. We argue that further refinement of aerosol pollution law is necessary to ensure that penalties for exceeding legally acceptable levels of atmospheric particulates are scientifically well founded and fair. [Copyright &y& Elsevier]

In this study a set of 340 PM10 and PM2.5 samples collected throughout 16 months at rural, an urban kerbside and an industrial background site (affected by the emissions from the ceramic manufacture and other activities) were interpreted. On the regional scale, the main PM10 sources were mineral dust (mainly Al2O3, Fe, Ti, Sr, CaCO3, Mg, Mn and K), emissions derived from power generation (SO4&z.dbnd6;, V, Zn and Ni), vehicle exhausts (organic and elemental carbon, NO3- and trace elements) and marine aerosol (Na, Cl and Mg). The latter was not identified in PM2.5. At the industrial site, additional PM10 sources were identified (tile covering in the ceramic production, petrochemical emissions and bio-mass burning from a large orange tree cultivation area). The contribution of each PM source to PM10 and PM2.5 levels experiences significant variations depending on the type of PM episode (Local-urban mainly in autumn–winter, regional mainly in summer, African or Atlantic episode), which are discussed in this study. The results show that it would be very difficult to meet the EU limit values for PM10 established for 2010. The annual mean PM levels are 22.0 μg PM10/m3 at the rural and 49.5 μg PM10/m3 and 33.9 μg PM2.5/m3 at the urban site. The natural contribution in this region, estimated at 6 μg/m3 of natural mineral dust (resulting from the African events and natural resuspension) and 2 μg/m3 of marine aerosol, accounts for 40% of the 2010 EU annual limit value (20 μg PM10/m3). Mineral dust concentrations at the urban and industrial sites are higher than those at the rural site because of the urban road dust and the ceramic-production contributions, respectively. At the urban site, the vehicle exhaust contribution (17 μg/m3) alone is very close to the 2010 EU PM10 limit value. At the rural site, the African dust is the main contributor to PM10 levels during the highest daily mean PM10 events (100th–97th percentile range). At the urban site, the vehicle exhaust product is the main contributor to PM10 and PM2.5 levels during the highest daily mean PM events (100th–85th percentile range). Mineral dust concentrations during African dust events accounts for 20–30 μg/m3 in PM10 and 10–15 μg/m3 in PM2.5. During non-African dust events, mineral dust derived from anthropogenic activities (e.g. urban road dust) is also a significant contributor to PM10, but not to PM2.5. [Copyright &y& Elsevier]

Concentrations of airborne particulates undergo a seasonal evolution characterised by a summer maximum in rural areas in Eastern Spain. In the summer months the daily mean concentrations of PM10 and TSP (PM) experience wide variations. In 3-day periods, increases in the PM concentrations from 15 to 30–40 μg/m3 are frequently reported, and increases from 15 to 40–60 μg/m3 occur several times throughout the summer. These variations are simultaneously reported at rural stations throughout the flat Ebro basin (600 m a.s.l.) and at mountain sites located at high altitude (>1000 m a.s.l.). The origin of high and low PM episodes was investigated by correlating PM levels with the concentrations of gaseous pollutants, and making use of meteorological analysis and satellite observations. The highest PM events (daily concentrations in the range 40–60 μg/m3) were documented during outbreaks of African dust. The second highest PM events (daily concentrations in the range 20–45 μg/m3) were recorded during regional episodes associated with ozone events. These summer regional PM episodes were induced by the abrupt orography surrounding the Western Mediterranean and by the regional meteorology, which favour the ageing of polluted air masses into the basin. These regional events occur in a synoptic meteorological context characterised by a weak pressure horizontal gradient over the Western Mediterranean often associated with the development of the Iberian thermal low, when advection of air masses is not significant. In this meteorological context, the transport of particulate pollutants from urban/industrial to rural sites is brought about by the breeze circulation at the coastal (sea breeze) and mountain (mountain breeze) sites. The persistence of this breeze circulation for several days (periods of up to 2 weeks were reported) results in a low renovation of air masses leading to an accumulation of airborne particulates in the regional atmosphere. The lowest PM events (daily concentrations <20 μg/m3) were reported during abrupt entries of Atlantic air into the Mediterranean. [Copyright &y& Elsevier]

Air pollution coming from industrial activities is a matter of interest since their emissions can seriously affect to the human health of nearby populations. A more detailed study about industrial emissions is required in order to discriminate different activities contributing to pollutant sources. In this sense, gaseous pollutants (NO 2 , SO 2 and O 3) and PM10 levels has been studied in a complex industrial area in the southwest of Spain (La Rabida and the nearby city of Huelva) during the period 1996–2017. Hourly, daily, monthly and annual variations of PM10 and gaseous pollutants concentrations point to the industrial activity as the main SO 2 source. Furthermore, traffic and resuspension emissions contribute to the NO 2 and PM10 levels, respectively. Results from chemical composition of PM10 at both sites during the period 2015–2017 are characterized by high concentrations of the crustal components derived from natural and local resuspension. Arsenic is found to be the main geochemical anomaly at La Rabida (annual mean of 7 ng m−3), exceeding the European annual target of 6 ng m−3, which supposes a risk for the nearby population. An emission source from Cu-smelter has been identified in La Rabida and Huelva. A second source corresponding to emissions from polymetallic sulfides handling in a port area has been described for the first time in La Rabida. In addition, arsenic speciation results have identified three different As impacts scenarios as a function of the dominant wind direction, the SO 2 episodes and the As extraction efficiency: impact of the Cu-smelter, impact of the bulk polymetallic sulfides and a mixed impact of both sources. Image 1 • Trends of PM10 and gaseous pollutants were studied in SW Spain in a 21-year period. • High As concentrations were observed for the period 2015–2017 at the sampling site. • Cu smelter and polymetallic sulfides were identified as the As emissions sources. • As speciation analysis allowed to discriminate two industrial emission sources. [ABSTRACT FROM AUTHOR]

Abstract Investigations into the respiratory health impacts of coal mine particulate matter (PM) face the challenge of understanding its chemical complexity. This includes highly variable concentrations of trace metals and metalloids such as Fe, Ti, Mn, Zn, Ni, V, Cr, Cu, Pb, Cd, Sb, As and Sn, which may be capable of inducing cell damage. Analysis of PM 10 and PM 2.5 samples size-separated from deposited coal mine dusts collected on PVC flat surfaces at a height of 1.5-2 m inside the second level in the Velenje lignite mine, Slovenia, demonstrates that some of these metallic elements (in this case Cu, Sb, Sn, Pb, Zn, As, Ni) can be concentrated in PM 2.5 , the most deeply inhalable and therefore potentially most bioreactive size fraction. These elements are likely to be mainly present in silicates, oxides, and perhaps antimonides and arsenides, rather than in the calcareous, carbonaceous or sulphide components which show no obvious affinity for PM 2.5. Whereas in the Velenje lignites concentrations of these metallic elements are low and so do not present any obvious extra health risk to the miners, this is unlikely to be the case in mines where unusually metal-enriched coals are being excavated. We therefore recommend that levels of potentially toxic elements in PM 2.5 should be assessed where metal- and metalloid-rich coals are being mined worldwide, especially given uncertainties relating to the efficiency of current dust suppression and respiratory protective equipment for such fine particle sizes. Highlights • The reasons for recent resurgence of coal mining lung disease are unclear. • We review metallic elements of potential health concern in coal dust. • Coal dust chemistry changes as particle size decreases. • Cu, Sb, Sn, Pb, Zn, As and Ni concentrate into the PM2.5 of airborne coal dust. [ABSTRACT FROM AUTHOR]

Abstract: The present work shows a straightforward procedure to indirectly estimate the chemical composition at a given site only from the determination of the PM concentrations, and the classification of the days according to the main meteorological scenarios. A previous study based on the mean chemical composition associated to the main meteorological scenarios is required. This experiment has been carried out with data from two monitoring sites in the North-Western Mediterranean, one regional and one suburban background. At both sites, one-year datasets on chemical PM10 composition were obtained. Based on these datasets, the mean PM10 compositions according to the most relevant meteorological situations were calculated for both locations. After that, the reconstruction of the chemical composition for all the days with available PM10 concentrations was completed. Subsequently, the estimated PM10 composition was compared with that determined experimentally. The comparison between the rebuilt and the experimental results was very satisfactory in the case of the regional background site, and relatively replaced in the other case. Furthermore, the validation of the method at the regional background site has been conducted from the reconstruction of a 4-year data base, and subsequent comparison with the experimental chemical composition. Our results show that it is possible to attain a good approach to the chemical composition at regional background sites, where local emission sources are negligible. Conversely, when the local sources rise in importance, i.e., at a suburban background site, the approach is suitable only for those components with a more regional origin and/or those from long range transport of air masses. [ABSTRACT FROM AUTHOR]

Abstract: This study has investigated the influence of synoptic weather patterns and long-range transport episodes on the concentration levels of airborne particulate matter (TSP, PM10 and PM2.5) and some major ions (SO4 2−, NO3 − and NH4 +) at a background rural station in central Spain. Air mass back-trajectories arriving at the site in 1999–2005 have been analysed by statistical methods. First, cluster analysis was used to group trajectories into 8 clusters depending on their direction and speed. Meteorological scenarios associated to each cluster have been obtained and interpreted. Then, the incidence of different air mass transport patterns on particle concentrations and composition recorded at this station was evaluated. This evaluation included PM10 and PM2.5 concentrations and chemical composition data, obtained at three representative sites of the Madrid air basin during sampling campaigns carried out in the course of the 1999–2005 period. Finally, a residence time analysis of trajectories was also performed to detect remote sources and transport pathways. Significantly elevated concentrations of TSP and PM10 were observed for Northern African flows as a consequence of the transport of mineral dust. Significant inter-cluster differences were also observed for PM2.5 and secondary inorganic compounds, with the highest concentrations associated with low baric gradient situations and Southern European flows. The residence time analysis confirmed that current TSP and PM10 concentrations in central Spain are likely to be influenced significantly by long-range transport of desert dust from different desert regions in North Africa. Furthermore, emissions from continental Europe with a high time of residence in the western and central areas of the Mediterranean basin, seem to significantly influence PM2.5 and secondary inorganic aerosol concentrations in this region. [Copyright &y& Elsevier]

Abstract: Puertollano is the largest industrial centre in central Spain, and includes fossil fuel burning power plants as well as petrochemical and fertilizer complexes. The coal-fired power plants use locally mined coal from extensive coal deposits which continue to be exploited and used locally. The coal deposits have a distinctive geochemistry, being particularly enriched in Sb and Pb, as well as several other metals/metalloids that include Zn and As. ICP-AES and ICP-MS chemical analysis of particulate matter samples (both PM10 and PM2.5) collected at Puertollano over a 57-week period in 2004–2005 reveals enhanced levels of several metallic trace elements, especially in the finer (PM2.5) aerosol fraction. Factor analysis applied to the data indicates that at least some of these metallic elements are likely to originate from hydrocarbon combustion: Sb and Pb are markers linked to the local coals, whereas V and Ni are, at least in the finer (PM2.5) fraction, likely associated with other anthropogenic sources. Other factors measured are related to natural sources such as crustal/mineral and sea spray particles. Our study provides an example of how chemical analysis of large numbers of ambient PM samples, combined with statistical factor analysis and coal geochemistry, can reveal airborne emissions from the combustion of specifically identifiable fuels. [Copyright &y& Elsevier]

• Desert dust episodes were more intense and frequent in Ahvaz than in Tehran. • The effect of PM10 in mortality was higher for dust than non-dust days in Ahvaz. • In Tehran the PM10 effect was slightly higher during non-dust days. • Effects were evidenced for PM2.5 only in Tehran for non-dust days at lags 2 and 3. • Middle East desert dust is an important risk factor to human health in this region. Increased atmospheric particulate matter (PM) concentrations are commonly observed during desert dust days in Iran, but there is still no evidence of their effects on human health. We aimed to evaluate the association between daily mortality and exposure to PM 10 and PM 2.5 during dust and non-dust days in Tehran and Ahvaz, two major Middle Eastern cities with different sources, intensity, and frequency of desert dust days. We identified desert dust days based on exceeding a daily PM 10 concentration threshold of 150 µg/m3 between 2014 and 2017, checking for low PM 2.5 /PM 10 ratio typical of dust days. We used a time-stratified case-crossover design to estimate the short-term effects of PM 10 and PM 2.5 concentrations on daily mortality during dust and non-dust days. Data was analyzed using conditional Poisson regression models. Higher concentrations of PM and frequency of desert dust days were observed in Ahvaz rather than Tehran. In Ahvaz, the effect of PM 10 at lag 0 was much higher during dust days, an increment of 10 μg/m3 was associated with 3.28% (95%CI = [2.42, 4.15]) increase of daily mortality, than non-dust days, 1.03% (95%CI = [−0.02, 2.08]), while in Tehran, was slightly higher during non-dust days, 0.72% (95%CI = [0.23, 1.23]), than in dust days, 0.49% (95%CI = [−0.22, 1.20]). No statistically significant associations were observed between PM 2.5 and daily mortality in Ahvaz, while in Teheran the effect of PM 2.5 increased significantly during non-dust days at lag 2, 1.89% (95%CI = [0.83, 1.2.95] and lag 3, 1.88% (95%CI = [0.83, 1.2.95]). The study provides evidence that exposure to PM during Middle East dust days is an important risk factor to human health in arid regions and areas affected by desert dust events. [ABSTRACT FROM AUTHOR]

The occurrence of African dust outbreaks over specific areas of the Mediterranean basin has been associated with increases in the PM 10 concentration levels and also in the mortality rates. Different hypothesis have been proposed in the last years to explain the processes by which African dust storms generates negative health effect over urban areas in southern Europe but are still not clear. Some authors have suggested the existence of an interaction between air pollutants from local sources and the occurrence of African dust outbreaks, with a consequent increase in the risk of mortality due to exposure to these anthropogenic emissions. This study sought to identify such a synergistic effect in the Madrid metropolitan area. To this end, an assessment of the influence of African dust on air quality levels, the vertical structure of the atmosphere over Madrid and daily mortality was carried out. Our results indicated that African dust caused a reduction of the mixing layer height and the surface wind speed, by reducing the amount of solar radiation reaching the ground. These facts favored the accumulation of air pollutants emissions from local anthropogenic sources. Moreover, when the dust contribution to PM 10 levels exceeded a threshold value (8 μg/m3), particulate matter mass (PM 10 , PM 2.5) and number (ultra-fine particles) concentration as well as levels of gaseous air pollutants (CO, NO and NO 2) registered at urban-background and urban-traffic monitoring sites, increased with statistical significance. In these conditions, it was found a statistically significant increase in risk of daily mortality in the PM 10 exposure. Hence, ambient air in Madrid was more toxic during African dust events of increasing intensity due to this synergistic effect. Because it can be envisaged that the frequency, duration and intensity of dust storms will increase in the north of Africa due to climate change, it will be a priority to put forward and assess proposals to mitigate the adverse effects on health, focused on the reduction of air pollutant emissions from local sources, as well as proposals regarding the adaptation of the population in urban areas across the Mediterranean basin. • African dust produced a reduction of the mixing layer height over Madrid. • Air pollutants emissions from local sources accumulated in the reduced mixing layer. • This synergistic effect made more toxic the ambient air in Madrid. • Risk of daily mortality in the PM 10 exposure increased in intense African dust events. • Measures for reducing harmful effects should focus on local anthropogenic sources. [ABSTRACT FROM AUTHOR]

Dust is a mixture of natural and anthropogenic particles originated from multiple sources, which can represent an hazard for human health. Playgrounds are a site of particularly concern, due to sand dust ingestion by toddlers and inhalation. In this study, 37 sands used in public playgrounds in the city of Barcelona were physico-chemically characterized also in relation to routine maintenance activities such as disinfection and sand renewal. The analyzed sands show a felsic mineralogy dominated by Na-feldspar, quartz, and, to a lesser extent, K-feldspar, with minor amounts of clay minerals, carbonates and hematite. Particle fractions below 10, 2.5 and 1 μm represent, on average, 0.65%, 0.17% and 0.07% of bulk volume, respectively, although, due to the human grinding, these initial fractions increased every year by a 18%, 5% and 2% respectively. Disinfection of sands effectively reduced only the NH 4 + concentration, among inorganic species. The average metal content was anthropogenically enriched, with respect to the upper continental crust, only for Sb and As. Both elements show high spatial variation indicating local sources such as road traffic for Sb (contributing mostly to the total concentration), and industry for As (also contributing with highly bioaccessible Sb, Cu and Zn). A clear inverse relationship between total concentrations of some elements and their leachable (Sb) and bioaccessible (Sb and Cr) fractions is observed. The most bioaccessible elements were Ca > Ni > Cu > Sr > Cd > Pb, all above the 25% of the total concentration. Bioaccessibility was higher for the carbonate-bearing particles and for the anthropic emitted metals (>50% of Ba, Cu, K, Pb and Zn). [ABSTRACT FROM AUTHOR]

Water spraying and/or chemical suppressants such as salts and polymers have been suggested to reduce road dust resuspension due to their capability to increase adhesion, and therefore the effective size and weight of particles, but contrasting results have been obtained so further testing are needed. This study presents the first results of street washing and Calcium Magnesium Acetate (CMA) efficiencies at two industrial roads (paved and unpaved) in the Mediterranean region where the high solar radiation, warm climate, and scarce precipitation, may play a key role in determining the efficiency of mitigation techniques Results show that, at both sites, street washing (water only) was more effective than CMA. Street washing made observe 18% (daily basis) and >90% (first hour) reductions of kerbside PM10 concentrations for the paved and unpaved road respectively, while with CMA PM10 decrease was generally lower and with less statistical significance. [ABSTRACT FROM AUTHOR]

In recent years monitoring the presence of psychotropic compounds in wastewater has been proposed as a tool to estimate community drug use. Measurement of drugs of abuse (DAs) in airborne particulate is currently being explored as an additional tool to evaluate drug use patterns in time and space, and identify potential emission sources. In this study, we comprehensively monitor the occurrence of 22 licit and illicit DAs and transformation products, belonging to 6 different chemical groups, in airborne particulate matter (PM10) in the city of Barcelona. In order to study spatial and temporal variations, samples were collected from 12 different selected locations on one weekday (Wednesday) and one weekend day (Saturday), during five consecutive weeks. A previously developed analytical methodology, based on pressurized liquid extraction (PLE) followed by liquid chromatography–tandem mass spectrometry (LC–MS/MS) determination, was adapted for analysis of the target compounds with satisfactory performance, ensuring reliability of results. Among the investigated compounds, cannabinol (CBN), cocaine (COC), and methamphetamine (MA) were found to be the most ubiquitous and abundant compounds in PM10 with concentrations ranging from 0.7 pg/m 3 (MA) to 6020 pg/m 3 (CBN). Significant differences in total DA concentrations in PM10 were observed across sampling days and locations. DA emissions were identified in highly densely populated areas, where popular commercial and nightlife zones are located. Psychoactive effects due to inhalation of measured concentrations are probably negligible; however, potential health effects due to chronic exposure have not been explored yet. [ABSTRACT FROM AUTHOR]

Abstract: This work was carried out in the framework of the Cal-Mex project, which focuses on investigating the atmosphere along Mexico–California border region. Sampling was carried out at two sites located in Tijuana urban area: Parque Morelos and Metales y Derivados. PM2.5 and PM10 24 h samples were collected every three days from 17th May 2010 to 27th June 2010, and were used for gravimetric and chemical analyses (major and minor elements, inorganic ions, organic and elemental carbon) of PM. A subsequent Positive Matrix Factorization (PMF) analysis was performed. PM2.5 and PM10 average concentrations during Cal-Mex were relatively lower compared to usual annual averages. Trace elements concentrations recorded in the present study were lower than those recorded in Mexico City in 2006, with the exception of Pb at Metales y Derivados, attributed to the influence of a specific industrial source, which also includes As, Cd and Tl. Apart from this industrial source, both urban sites were found to be affected by similar sources with respect to bulk PM. Fine PM (PM2.5) was mainly apportioned by fueloil and biomass combustion and secondary aerosols, and road traffic. Coarse PM (PM2.5–10) was mainly apportioned by a mineral source (sum of road dust resuspension, construction emissions and natural soil) and fresh and aged sea salt. The road traffic was responsible for more than 60% of the fine elemental carbon and almost 40% of the fine organic matter. [Copyright &y& Elsevier]

Abstract: This work presents a summary of the results obtained from a study of the impact of African dust on levels of atmospheric suspended particulate matter registered among different monitoring sites in the Madrid Air Basin, in the centre of the Iberian Peninsula. African dust outbreaks were identified over the period 2001–2008. Lidar measurements helped to assess the temporal evolution of the dust layers and subsequent impact on the surface boundary layer. Monthly trends were analyzed, revealing a late spring/summer maximum occurrence of episodes. The most common synoptic meteorological situations causing the transport of the African dusty air masses were also identified over the seasons. Time series of particulate matter daily concentrations recorded across Air Quality Network monitoring stations and sampling campaigns were collected and analysed. Our results show the contribution of mineral dust to PM10 (particulate matter lower than 10μm, aerodynamic diameter) during African dust outbreaks to be significantly high at rural and urban sites of the Madrid Air Basin, giving rise to exceedances of the PM10 daily limit value (50μg/m3). This result is especially relevant since European directive 2008/50/EC on air quality, takes into account the potential exceedance of the PM10 daily limit value, due to the transport of natural particles from arid regions. [Copyright &y& Elsevier]

Abstract: In spite of the high air quality and health relevance of PM emissions from road dust resuspension in large cities, very little is known on their temporal variability, severely hampering a reliable description of population exposure by dispersion models. We have experimentally monitored the mobile dust load (only inhalable fraction) in two different European urban environments resulting in the first empirical description of the temporal variation of road dust emission strength. In Central (The Netherlands) and Southern (Spain) European environments the loadings of mobile road dust particles <10 μm were found to be generally constant on a day-to-day scale, except during and in the hours immediately after rain events when the mobility of particles drops dramatically to values close to zero. After the rain event the mobile dust load increases exponentially tending to reach again the maximum value, result of the equilibrium between mobilization/buildup of dust and moistening/resuspension processes. The mobilization/buildup of particles smaller than 10 μm was found to be three times faster in Barcelona than in Utrecht, in relation to higher solar radiation. In Barcelona the recovery of mobile road dust reached 50%, 75%, and 90% of the maximum value after 8, 16 and 27 h, respectively. These values were independent of amounts of rain. In Utrecht the same thresholds were reached after, 28, 55 and 90 h, respectively. Our observations may suggest that, for reducing road dust emissions, light but frequent moistening of roads might be more effective than intensive occasional cleanings. [Copyright &y& Elsevier]

Abstract: The primary aim of this study was to quantify the contribution of road dust to airborne particulate matter (PM10) and evaluate the effects of street washing on the mitigation of resuspension. With this purpose an intensive campaign was carried out in a heavily trafficked central road of Madrid (Spain) including PM10 sampling and chemical analysis. PM10 daily levels during dry, unwashed conditions were 2–15% higher than those present during the day after nightly street washing. However, this reduction is lower than the standard deviation of the PM10 measurements. The diurnal variation of PM10 revealed that a reduction in PM10 was noticeable only during the morning hours. The emission sources for the urban area of Madrid were resolved by means of a receptor model, Positive Matrix Factorization, PMF. The results showed that the main sources were vehicle emissions, road dust, secondary aerosol including sulphate and nitrate, and soil. Vehicle emissions and road dust were the major contributor to PM10 particle mass with similar average contributions of 31% and 29% respectively. The effect of street washing was also evaluated by examining the daily variation of the road dust source contribution between days with and without street washing. The mass contribution from the road dust source was ∼2 μg m−3 lower during the days that street washing was implemented with this corresponding to a reduction of 15% of its mass contribution during the days that the road surface was left untreated. [Copyright &y& Elsevier]

Abstract: Samples of particulate matter were collected during the period from October 2006 through September 2007 in a rural station located 12 km from the city of Colima. A total of 3600 particles were analyzed by SEM-EDS and then classified by their chemical composition and morphology in order of abundance: those rich in C, Fe, Si–Al, Cl–Na, Ca, Ba; and to a lesser abundance, particles rich in heavy metals such as Pb and V–Ni were observed. A factorial analysis was carried out to determine the main elements related with the emission sources such as crustal/farming; fuel-oil; marine; volcanic activity and industry. Trough the seasons, the dominant winds causes the presence of anthropogenic particles in the rural site. The information presented in this study aims to give insight and detailed of the analysis of the morphological characteristics and chemical composition of atmospheric particles at individual level in a rural site from Colima State, Mexico. [Copyright &y& Elsevier]

This paper synthesizes data on aerosol (or particulate matter, PM) chemical characteristics, which were obtained in European aerosol research activities at natural, rural, near-city, urban, and kerbside sites over the past decade. It includes only two (nearby) sites in the semi-arid Mediterranean area, and lacks data from Eastern Europe. PM chemical compositions are compared with the PM mass concentrations in PM10, PM2.5, and further size resolved PM fractions (chemical mass closure). Such data sets are more comprehensive than those currently provided by air quality monitoring networks (e.g. EMEP, EUROAIRNET). Data available from 24 sites in Europe were reviewed. They were processed and plotted to allow comparisons in spite of differences in the sampling and analytical techniques used in various studies. A number of conclusions are drawn among which are the following.Organic matter appears to be the major component of PM10 and PM2.5, except at natural and rural background sites, where sulphate contribution may be larger. Mineral dust shows up as a major component of PM10 at kerbside sites. Black carbon contributes 5–10% to PM2.5 and somewhat less to PM10 at all sites, including the natural background sites. Its contribution seems higher (15–20%) at some of the kerbside sites, but these data may be affected by analytical artefacts. On days when PM10 >50 μg m−3, nitrate concentrations can overtake organic matter concentrations in PM10 and PM2.5. High PM concentration episodes are often observed in cold periods, when the pollutant dispersion is least. Measurements indicate that the condensation in the particle phase of semi-volatile species like nitrate and (unspecified) organics is also favoured by cold temperatures. In particles with a diameter <150 nm (i.e., most atmospheric particles), organic matter and black carbon are by far the major components.More data are known to be available within the scientific community, which could enrich the present data set and strengthen the conclusions made above. Most of them are not made available yet. The investment in new approaches, which would bridge the technological gap between scientific measurements and regulatory monitoring networks, is strongly needed. [Copyright &y& Elsevier]

This paper synthesizes data on aerosol (particulate matter, PM) physical characteristics, which were obtained in European aerosol research activities at free-troposphere, natural, rural, near-city, urban, and kerbside sites over the past decade. It covers only two sites in the semi-arid Mediterranean area, and lacks data from Eastern Europe. The data include PM10 and/or PM2.5 mass concentrations, and aerosol particle size distributions. Such data sets are more comprehensive than those currently provided by air quality monitoring networks (e.g. EMEP, EUROAIRNET). Data available from 31 sites in Europe (called “The Network”) were reviewed. They were processed and plotted to allow comparisons in spite of differences in the sampling and analytical techniques used in various studies. A number of conclusions are drawn as follows:Background annual average PM10 and PM2.5 mass concentrations for continental Europe are 7.0±4.1 and 4.8±2.4 μg m−3, respectively.The EU 2005 annual average PM10 standard of 40 μg m−3 is exceeded at a few sites in The Network. At all near city, urban and kerbside sites, the EU 2010 annual average PM10 standard of 20 μg m−3, as well as the US-EPA annual average PM2.5 standard of 15 μg m−3 are exceeded. In certain regions, PM10 and PM2.5 in cities are strongly affected by the regional aerosol background.There is no “universal” (i.e. valid for all sites) ratio between PM2.5 and PM10 mass concentrations, although fairly constant ratios do exist at individual sites. There is no universal correlation between PM mass concentration on the one hand, and total particle number concentration on the other hand, although a ‘baseline’ ratio between number and mass is found for sites not affected by local emissions. This paper is the first part of two companion papers of which the second part describes chemical characteristics. [Copyright &y& Elsevier]

Road dust resuspension has a significant contribution to the atmospheric particulate matter levels in urban areas, but loadings, emission factors, and chemical source profiles vary geographically, hampering the accuracy of emission inventories and source contribution estimates. Given the dearth of studies on the variability of road dust, in the present study, an in-situ resuspension chamber was used to collect PM 10 samples from seven representative streets in Viana do Castelo, the northernmost coastal city in Portugal. PM 10 samples were analysed for organic and elemental carbon by a thermo-optical technique, elemental composition by ICP-MS and ICP-AES, and organic constituents by GC–MS. Emission factors were estimated to be, on average, 340 and 41.2 mg veh−1 km−1 for cobbled and asphalt pavements, respectively. Organic carbon accounted for 5.56 ± 1.24% of the PM 10 mass. Very low concentrations of PAHs and their alkylated congeners were detected, denoting a slight predominance of petrogenic compounds. Si, Al, Fe, Ca and K were the most abundant elements. The calculation of various geochemical indices (enrichment factor, geoaccumulation index, pollution index and potential ecological risk) showed that road dust was extremely enriched and contaminated by elements from tyre and brake wear (e.g. Sb, Sn, Cu, Bi and Zn), while lithophile elements showed no enrichment. For As, the geochemical and pollution indices reached their maximum in the street most influenced by agricultural activities. Sb, Cd, Cu and As can pose a very high ecological risk. Sb can be regarded as the pollutant of highest concern, since it represented 57% of the total ecological risk. Hazard indices higher than 1 for some anthropogenic elements indicate that non-carcinogenic effects may occur. Except for a street with more severe braking, the total carcinogenic risks can be considered insignificant. Unlabelled Image • The thoracic fraction of road dust was sampled with an in-situ resuspension chamber. • Emission factors of 340 (cobbled) and 41 (asphalt) mg PM 10 veh−1 km−1 were estimated. • Road dust was extremely contaminated by elements from tyre and brake wear. • Elements from tyre and brake wear can pose a very high ecological risk. • High pollution indices for arsenic in samples impacted by agricultural activities. [ABSTRACT FROM AUTHOR]

Biomass burning is a major air pollution problem all around the world. However, the identification and quantification of its contribution to ambient aerosol levels is a difficult task due to the generalized lack of observations of molecular markers. This paper presents the results of a yearlong study of organic constituents of the atmospheric aerosol at a rural site in southern Spain (Villanueva del Arzobispo, Jaén). Sampling was performed for PM 10 and PM 2.5 , and a total of 116 and 115 samples, respectively, were collected and analyzed by GC/MS, quantifying 77 organic compounds. Higher levels of organic pollutants were recorded from November to March, coinciding with the cold season when domestic combustion is a common practice in rural areas. This jointly with adverse meteorological conditions, e.g. strong atmospheric stability, produced severe pollution episodes with high PM x ambient levels. High daily concentrations of tracers were reached, up to 26 ng m−3 for B(a)P and 6065 ng m−3 for levoglucosan in PM 2.5 , supporting that biomass burning is a major source of pollution at rural areas. A multivariate statistical study based on factor and cluster analysis, was applied to the data set with the aim to distinguish sources of organic compounds. The main resulting sources were related with biomass combustion, secondary organic aerosol (SOA), biogenic emissions, lubricating oil and soil organic components. A preliminary organic source profile for olive wastes burning was evaluated, based on cluster results, showing anhydrosacharides and xylitol are the main emitted compounds, accounting for more than 85% of the quantified compounds. Other source compounds were fatty acids, diacids, aliphatics, sugars, sugar alcohols, PAHs and quinones. • Air pollution exceeds PM10 & PM2.5 limit values in Spanish rural areas in winter. • GC/MS characterization of 77 polar and apolar organic compounds. • Daily concentrations up to 26 ng m−3 of Benzo(a)pyrene were reached. • Biomass burning was identified as the main source of many organic compounds. • Other sources were biogenic emissions, SOA, soil dust and lubricating oil. [ABSTRACT FROM AUTHOR]