Jorge Pey

Coarse particles from Saharan dust and daily mortality.

Background: Winds from the Sahara-Sahel desert region regularly transport large amounts of dust to the Americas, North Africa, and Europe. The presence of high dust concentrations for long periods of time, and the interaction between dust and man-made air pollution, raise concerns about adverse health effects and appropriate interventions by health authorities. This study tested the hypothesis that outbreaks of Saharan dust exacerbate the effects of man-made pollution, specifically fine and coarse particulate matter (PM2.5 and PM10-2.5, respectively) on daily mortality. Methods: We investigated the effects of exposure to PM10-2.5 and PM2.5 between March 2003 and December 2004 in Barcelona (Spain) on daily mortality; changes of effects between Saharan and non-Saharan dust days were assessed using a time-stratified case-crossover design. We studied the chemical composition of particulate matter to explain changes of effects. Results: The study included 24,850 deaths. During Saharan dust days, a daily increase of 10 &mgr;g/m3 of PM10-2.5 increased daily mortality by 8.4% (95% confidence interval = 1.5%–15.8%) compared with 1.4% (−0.8% to 3.4%) during non-Saharan dust days (P value for interaction = 0.05). In contrast, there was no increased risk of daily mortality for PM2.5 during Saharan dust days. Although coarse particles seem to be more hazardous during Saharan dust days, differences in chemical composition did not explain these observations. Conclusions: Saharan dust outbreaks may have adverse health effects. Further investigation is needed to understand the role of coarse particles and the mechanism by which Saharan dust increases mortality.

Variability of Particle Number, Black Carbon, and PM10, PM2.5, and PM1 Levels and Speciation: Influence of Road Traffic Emissions on Urban Air Quality

Measurements of particle number concentration (N), black carbon (BC), and PM 10 , PM 2.5 , and PM 1 levels and speciation were carried out at an urban background monitoring site in Barcelona. Daily variability of all aerosol monitoring parameters was highly influenced by road traffic emissions and meteorology. The levels of N, BC, PM X , CO, NO, and NO 2 increased during traffic rush hours, reflecting exhaust, and non-exhaust traffic emissions and then decreased by the effect of breezes and the reduction of traffic intensity. PM 2.5–10 levels did not decrease during the day as a result of dust resuspension by traffic and wind. N showed a second peak, registered in the afternoon and parallel to O 3 levels and solar radiation intensity, that may be attributed to photochemical nucleation of precursor gases. An increasing trend was observed for PM 1 levels from 1999 to 2006, related to the increase in the traffic flow and the diesel fleet in Barcelona. PM composition was highly influenced by road traffic emissions, with exhaust emissions being an important source of PM 1 and dust resuspension processes of PM 2.5–10 , respectively.

The effects of particulate matter sources on daily mortality: a case-crossover study of Barcelona, Spain.

Background: Dozens of studies link acute exposure to particulate matter (PM) air pollution with premature mortality and morbidity, but questions remain about which species and sources in the vast PM mixture are responsible for the observed health effects. Although a few studies exist on the effects of species and sources in U.S. cities, European cities—which have a higher proportion of diesel engines and denser urban populations—have not been well characterized. Information on the effects of specific sources could aid in targeting pollution control and in articulating the biological mechanisms of PM. Objectives: Our study examined the effects of various PM sources on daily mortality for 2003 through 2007 in Barcelona, a densely populated city in the northeast corner of Spain. Methods: Source apportionment for PM ≤ 2.5 μm and ≤ 10 µm in aerodynamic diameter (PM2.5 and PM10) using positive matrix factorization identified eight different factors. Case-crossover regression analysis was used to estimate the effects of each factor. Results: Several sources of PM2.5, including vehicle exhaust, fuel oil combustion, secondary nitrate/organics, minerals, secondary sulfate/organics, and road dust, had statistically significant associations (p < 0.05) with all-cause and cardiovascular mortality. Also, in some cases relative risks for a respective interquartile range increase in concentration were higher for specific sources than for total PM2.5 mass. Conclusions: These results along with those from our multisource models suggest that traffic, sulfate from shipping and long-range transport, and construction dust are important contributors to the adverse health effects linked to PM.

Interpretation of the variability of levels of regional background aerosols in the Western Mediterranean

Results on interpretation of the variability of regional background PM levels in the Western Mediterranean basin (WMB) are presented. Mean PM levels recorded at Montseny, MSY (North-Eastern Spain) in the 2002--2007 period reached 17, 13 and 11 microg/m3 of PM10, PM2.5 and PM1, respectively. The daily evolution of PM levels is regulated by the breeze circulation (mountain and sea breezes). PM levels are lower at the rural sites at night owing to the nocturnal drainage flows and to the lowering of the mixing layer height below the MSY high. These nocturnal low levels allowed us to estimate the continental background PM levels. At midday, the atmospheric pollutants accumulated in the pre-coastal depression are transported upwards by the breeze, increasing PM levels. Maximum PM10 levels were recorded in summer, and February--March and November, and minimum values in the rest of the year coinciding with the highest frequency of Atlantic advection. PM peak episodes attributed to Saharan dust outbreaks were recorded in summer and February-March. In addition, anticyclonic situations (February--March and November) may impact in elevated rural areas by increasing hourly levels of PM1 up to 75 microg/m3. This scenario induces the stagnation of pollutants in the pre-coastal depression. Solar radiation activates mountain winds, transporting polluted air masses from the valleys to elevated areas resulting in an increase of fine PM levels in areas outside the boundary layer. A significant decrease in PM annual means (40% and 34% for the entire monitoring period, 7 microgPM10/m3 and 5 microgPM2.5/m3) was recorded at MSY between 2002 and 2007. There appears to be no single cause behind these trends. This could partially be ascribed to the varying frequency and intensity of Saharan dust episodes, but also to large-scale meteorological processes or cycles, and/or to local or meso-scale processes such as nearby anthropogenic emission sources.

Short-term effects of particulate matter on total mortality during Saharan dust outbreaks: A case-crossover analysis in Madrid (Spain)

BACKGROUND The role of Saharan dust outbreaks on the relationship between particulate matter and daily mortality has recently been addressed in studies conducted in Southern Europe, although they have not given consistent results. METHODS We investigated the effects of coarse (PM(10-2.5)) and fine particulate matter (PM(2.5)) in Madrid on total mortality during Saharan dust and non-dust days using a case-crossover design. RESULTS During Saharan dust days, an increase of 10mg/m(3) of PM(10-2.5) raised total mortality by 2.8% compared with 0.6% during non-dust days (P-value for interaction=0.0165). CONCLUSION We found evidence of stronger adverse health effects of PM(10-2.5) during Saharan dust outbreaks effects for impacted European populations, but not for PM(2.5). Further research is needed to understand mechanisms by which Saharan dust increases risk of mortality.

Intense winter atmospheric pollution episodes affecting the Western Mediterranean

The geographic location of the Western Mediterranean Basin and its peculiar topography, the climatic conditions and the intense anthropogenic and natural emissions of atmospheric pollutants are key factors necessary to interpret the atmospheric aerosol phenomenology over this area. During the cold season it is common to have severe atmospheric particulate matter (PM) pollution episodes (of an anthropogenic origin) affecting this region, not only in the urban and industrial areas but also in the regional and rural sites. During these episodes, the midday hourly PM(1) levels at regional background sites are in many cases higher than those at urban areas. Around 10% of the days under winter anticyclonic conditions registered similar PM(1) levels at the regional background than at the urban area and, sporadically the daily PM(1) levels at the regional background sites may exceed those at urban sites. Furthermore, the very high hourly PM(1) levels measured at regional background sites during these episodes are not regularly attained in the closest urban areas, which leads to the hypothesis that an important formation of secondary aerosols occurs during the transport of the polluted air masses towards the elevated rural sites. The interpretation of the variability of PM levels and composition (2002-2008) at one urban site (Barcelona) and at one regional background site (Montseny) allows us to illustrate the phenomenology of these scenarios, to quantify the mean annual contributions to the PM levels and to identify their main tracers. Ammonium nitrate appears to be the most abundant compound during these scenarios, although organic species and trace metals also increase markedly. Owing to the intensity, composition and recurrence of these atmospheric pollution episodes, important health, climatic and ecological implications may be derived.

Saharan dust, particulate matter and cause-specific mortality: A case–crossover study in Barcelona (Spain)

BACKGROUND Studies measuring health effects of Saharan dust based on large particulate matter (PM) fraction groups may be masking some effects. Long distant transport reduces the amount of heavier and larger particles in the Saharan air masses increasing the relative contribution of smaller particles that may be more innocuous. This study investigates the association between different PM fractions and daily mortality during Saharan and non-Saharan days in Barcelona, Spain. METHODS We collected daily PM(1), PM(2.5-1) and PM(10-2.5) fractions, and cause-specific mortality (cardiovascular, respiratory and cerebrovascular) between March 2003 and December 2007. Changes of effects between Saharan and non-Saharan dust days were assessed using a time-stratified case-crossover design. RESULTS During non-Saharan dust days we found statistically significant (p<0.05) effects of PM(10-2.5) for cardiovascular (odds ratio for increase of an interquartile range, OR=1.033, 95% confidence interval: 1.006-1.060) and respiratory mortality (OR=1.044, 95% CI: 1.001-1.089). During Saharan dust days strongest cardiovascular effects were found for the same fraction (OR=1.085, 95% CI: 1.017-1.158) with an indication of effect modification (p=0.111). Effects of PM(2.5-1) during Saharan dust days were about the double than in non-dust days for cardiovascular and respiratory mortality, but these differences were not statistically significant. CONCLUSION Our results using independent fractions of PMs provide further evidence that the effects of short-term exposure to PM during Saharan dust days are associated with both cardiovascular and respiratory mortality. A better understanding of which of the different PM size fractions brought by Saharan dust is more likely to accelerate adverse effects may help better understand mechanisms of toxicity.

Natural sources of atmospheric aerosols influencing air quality across Europe

Atmospheric aerosols are emitted by natural and anthropogenic sources. Contributions from natural sources to ambient aerosols vary widely with time (inter-annual and seasonal variability) and as a function of the distance to source regions. This work aims to identify the main natural sources of atmospheric aerosols affecting air quality across Europe. The origin, frequency, magnitude, and spatial and temporal variability of natural events were assessed for the years 2008 and 2009. The main natural sources of atmospheric aerosols identified were African dust, sea spray and wildfires. Primary biological particles were not included in the present work. Volcanic eruptions did not affect air quality significantly in Europe during the study period. The impact of natural episodes on air quality was significant in Southern and Western Europe (Cyprus, Spain, France, UK, Greece, Malta, Italy and Portugal), where they contributed to surpass the PM10 daily and annual limit values. In Central and Northern Europe (Germany, Austria and Latvia) the impact of these events was lower, as it resulted in the exceedance of PM daily but not annual limit values. Contributions from natural sources to mean annual PM10 levels in 2008 and 2009 ranged between 1 and 2 μg/m(3) in Italy, France and Portugal, between 1 and 4 μg/m(3) in Spain (10 μg/m(3) when including the Canary Islands), 5 μg/m(3) in UK, between 3 and 8 μg/m(3) in Greece, and reached up to 13 μg/m(3) in Cyprus. The evaluation of the number of monitoring stations per country reporting natural exceedances of the daily limit value (DLV) is suggested as a potential tool for air quality monitoring networks to detect outliers in the assessment of natural contributions. It is strongly suggested that a reference methodology for the identification and quantification of African dust contributions should be adopted across Europe.

Desert Dust Outbreaks in Southern Europe: Contribution to Daily PM10 Concentrations and Short-Term Associations with Mortality and Hospital Admissions

Background: Evidence on the association between short-term exposure to desert dust and health outcomes is controversial. Objectives: We aimed to estimate the short-term effects of particulate matter ≤ 10 μm (PM10) on mortality and hospital admissions in 13 Southern European cities, distinguishing between PM10 originating from the desert and from other sources. Methods: We identified desert dust advection days in multiple Mediterranean areas for 2001–2010 by combining modeling tools, back-trajectories, and satellite data. For each advection day, we estimated PM10 concentrations originating from desert, and computed PM10 from other sources by difference. We fitted city-specific Poisson regression models to estimate the association between PM from different sources (desert and non-desert) and daily mortality and emergency hospitalizations. Finally, we pooled city-specific results in a random-effects meta-analysis. Results: On average, 15% of days were affected by desert dust at ground level (desert PM10 > 0 μg/m3). Most episodes occurred in spring–summer, with increasing gradient of both frequency and intensity north–south and west–east of the Mediterranean basin. We found significant associations of both PM10 concentrations with mortality. Increases of 10 μg/m3 in non-desert and desert PM10 (lag 0–1 days) were associated with increases in natural mortality of 0.55% (95% CI: 0.24, 0.87%) and 0.65% (95% CI: 0.24, 1.06%), respectively. Similar associations were estimated for cardio-respiratory mortality and hospital admissions. Conclusions: PM10 originating from the desert was positively associated with mortality and hospitalizations in Southern Europe. Policy measures should aim at reducing population exposure to anthropogenic airborne particles even in areas with large contribution from desert dust advections. Citation: Stafoggia M, Zauli-Sajani S, Pey J, Samoli E, Alessandrini E, Basagaña X, Cernigliaro A, Chiusolo M, Demaria M, Díaz J, Faustini A, Katsouyanni K, Kelessis AG, Linares C, Marchesi S, Medina S, Pandolfi P, Pérez N, Querol X, Randi G, Ranzi A, Tobias A, Forastiere F, MED-PARTICLES Study Group. 2016. Desert dust outbreaks in Southern Europe: contribution to daily PM10 concentrations and short-term associations with mortality and hospital admissions. Environ Health Perspect 124:413–419; http://dx.doi.org/10.1289/ehp.1409164

Chemical fingerprint and impact of shipping emissions over a western Mediterranean metropolis: Primary and aged contributions

An intensive monitoring campaign was carried out in the harbor of Barcelona (Spain) to quantify the contribution of primary shipping emissions (PSE) on PM10. Chemical composition of inorganic species, as well as OC and EC, was completed, and a source apportionment analysis by Positive Matrix Factorization was conducted. Among the 6 sources extracted, two were linked to harbor emissions: dusty materials released in different areas along the harbor and fuel-oil combustion. On average, harbor emissions accounted for 31% of the PM10 mass. Since the chemical signature of PSE was not determined neither their contribution was obtained, additional approaches were followed and mainly consisted in: 1) the evaluation of V/Ni and V/Cu ratios to identify those days affected by PSE; 2) the identification of the chemical components increasing under the influence of PSE; 3) the calculation of the daily and average PSE from their experimentally-determined chemical signature and the experimental concentrations of vanadium. As a result, the contribution of PSE was estimated in 0.84 μg m(-3) (2.7% of PM10) and the residual fuel-oil combustion factor (3.6 μg m(-3), 12% of PM10) was interpreted as aged shipping emissions. The present study splits the contribution of shipping emissions into primary and aged, and highlights the importance of atmospheric mixing and aging processes in western Mediterranean atmospheres. In the case of shipping emissions, the aged products were found to be dominant with respect to the primary ones even in the vicinity of the source.