Enrique Mantilla

Meteorology and photochemical air pollution in Southern Europe: Experimental results from EC research projects

The MECAPIP project of EC has served to document the summer atmospheric circulations and the related air pollution dynamics over Spain and the Western Mediterranean. The first includes surface wind convergence over the Iberian peninsula, large-scale compensatory subsidence over the surrounding coastal areas, and the formation of re-circulatory cells as a result of the sea breezes combining with up-slope winds and their return and compensatory flows. With respect to the second, experimental evidence indicates that, (a) during the day the sea breezes can transport ozone 60 to 100, or more, km inland, (b) during the afternoon, photo-oxidants are injected 3 to 5 km into the mid-troposphere over the Spanish Central plateau, and (c) stratified reservoir layers, stacked up to ≈2–3 km high, build up along the Mediterranean coast. These retain ozone from one day to the next and following days. The lowermost layers are drawn inland by the sea breeze during the day, and the aged pollutants can react with new coastal emissions. All of these processes have a marked diurnal cycle and can recur for many consecutive days or weeks. Tracer experiments show that the average return times for pollutants can be of the order of 2–3 d. This includes first emission on the coast in the morning, travel inland with sea breeze, convective and/or orographic injection in return flows followed by layering and subsidence over the sea, and their final re-entry with the sea breeze a few days later. All together, those mechanisms can be considered to form a large “photochemical reactor” which operates almost every day from spring to fall. It can generate ozone levels 2 to 3 times higher than EC directives for damages to vegetation 65 μg m−3 (≈32 ppbv), 24 h avg. This work presents a summary of results illustrating some of the above-mentioned processes. Similar situations are also expected to occur in other Mediterranean regions.

Comparative PM10-PM2.5 source contribution study at rural, urban and industrial sites during PM episodes in Eastern Spain

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=, 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 microg PM10/m3 at the rural and 49.5 microg PM10/m3 and 33.9 microg PM2.5/m3 at the urban site. The natural contribution in this region, estimated at 6 microg/m3 of natural mineral dust (resulting from the African events and natural resuspension) and 2 microg/m3 of marine aerosol, accounts for 40% of the 2010 EU annual limit value (20 microg 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 microg/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 microg/m3 in PM10 and 10-15 microg/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.

Ozone Cycles in the Western Mediterranean Basin: Interpretation of Monitoring Data in Complex Coastal Terrain

Abstract In summer, the complex layout of the coasts and mountains surrounding the western Mediterranean basin favors the development of mesoscale atmospheric recirculations and the formation of ozone reservoir layers above the coastal areas and the sea. Tropospheric ozone cycles vary here according to location and exposure of the monitoring station in relation to the flows and reservoir layers, and large differences can be encountered within tens of kilometers. The basic premise for this work is that the representativeness of any station is determined by the (fore)knowledge of the processes affecting the site, at the proper timescales and space scales within its region. Thus, available data have been combined with mesoscale analysis and modeling to interpret the observed summer ozone cycles for the monitoring network at Castellon, on the Spanish east coast. The area is approximately 120 km by 120 km, is backed by coastal mountains, and includes the following: a conurbation, industries, and a densely trav...

Seasonal evolution of suspended particles around a large coal-fired power station: particulate levels and sources

The present work focuses on the seasonal evolution of suspended particles (TSP and PM10) around the Teruel power station in NE Spain. The specific objectives are the determination of the spatial and time variability of levels of suspended particles, and their relationship with the power plant emissions and other natural or anthropogenic (local or external) particulate sources. The results show a marked seasonal trend, along the study period (July 1995–August 1996) which is characterized by particulate levels that were higher in spring–summer and decreased progressively towards winter. This trend may be related to (a) higher summer oxidation which increased levels of secondary particles, (b) higher convective circulation in summer which raised levels of soil-related particles and anthropogenic particles, (c) higher frequency of intrusion episodes of Sahara air masses in summer and spring, and (d) lower aerosol scavenging potential in summer. The similarity between the seasonal evolutions of daily mean levels of SO2 and particulates is due to the fact that both are partially controlled by the solar cycle. The long range transport particulate inputs affecting this area of the Mediterranean Basin (mainly Sahara air mass intrusions) account for major particulate peaks recorded at the monitoring stations. The influence of the emissions from the power plant in the PM10 and TSP levels is evidenced only in periods with a low background particulate levels. The results demonstrate that even PM10 levels are still highly influenced by the Saharian and European particulate inputs. Therefore, for an accurate environmental assessment, probably PM2.5 should be monitored instead of TSP or PM10, in order to quantify the influence of the power plant emissions on the bulk atmospheric particulate levels. The results obtained from the air back-trajectory analysis and their comparison with the time series of daily PM10 levels allowed the classification of the major external particulate inputs as a function of the particulate levels.

Mineral composition of atmospheric particulates around a large coal-fired power station

Abstract The present work is a mineralogical study of atmospheric particulates around a large coal-fired power station in NE Spain. After a mineralogical study of the fly ash sampled in the electrostatic precipitators of the power station, several chemical and mineralogical patterns of the fly ash were employed as tracers of the power station emissions. At the same time, the study focused on the downwind evolution of secondary particulate matter, especially particulate sulphate. The studies on the mineralogy of air borne dust allowed us to distinguish between natural and anthropogenic particles. The major mineral phases identified in the samples studied were: gypsum, calcite, clay minerals (kaolinite, clinochlore and illite), quartz, talc and hematite. In addition to these mineral phases which are frequently present in the atmospheric particulate matter of the studied area, other mineral phases, such as feldspars, mullite, and copper sulphates, were detected in minor proportions. The results show that some mineralogical and morphological characteristics of the atmospheric particulate matter may be used as tracers of the influence of coal-fired power plant emissions. These characteristics include spherical morphologies, aluminosilicate glass, mullite, hematite and sulphate-fly ash associations. The possible buffering effect of atmospheric Ca-bearing minerals to neutralize the sulphate deposition is investigated.

Seasonal evolution of suspended particles around a large coal-fired power station: Chemical characterization

Abstract The present work focuses on the seasonal evolution of total suspended particles (TSP) around the Teruel power station in Northeastern Spain. The results show a marked seasonal trend, along the sampling period (July 1995–July 1996), which is characterized by levels of the elements studied in TSP that were higher (up to one order of magnitude) in spring-summer and decreased progressively towards winter. This trend contrasts with the seasonal evolution reported by most of the studies carried out in industrial and urban areas in Central and Northern Europe. The origin of this seasonal TSP trend may be related to: (a) higher summer oxidation which increased levels of secondary TSP; (b) higher convective circulation in summer which raised levels of soil-related particles and primary anthropogenic particles; (c) higher frequency of intrusion episodes of Sahara air masses in summer and spring; and (d) lower aerosol scavenging potential in summer. A clear grain-size fractionation was observed for the different ions determined. SO 4 2− and NH 4 + were concentrated in the finest grain-size fraction (0.3−0.6 μm); NO 3 − , Cl − , K + , Mg 2+ , Na + and minor amounts of NH 4 + were concentrated in the 1.2−5.0 μm fractions; and Ca 2+ increased with the particle diameter. S-bearing species were (NH 4 ) 2 SO 4 (mascagnite), (NH 4 ) 2 Ca(SO 4 ) 2 · H 2 O (koktaite) and CaSO 4 · 2H 2 O (gypsum). Mascagnite was the dominant species in the finest grain size fraction (0.3−0.6 μm), whereas koktaite was also present in the 0.6−1.2 μm fraction, and gypsum predominated in the other fractions.

Climatic feedbacks and desertification: The Mediterranean model

Abstract Mesometeorological information obtained in several research projects in southern Europe has been used to analyze perceived changes in the western Mediterranean summer storm regime. A procedure was developed to disaggregate daily precipitation data into three main components: frontal precipitation, summer storms, and Mediterranean cyclogenesis. Working hypotheses were derived on the likely processes involved. The results indicate that the precipitation regime in this Mediterranean region is very sensitive to variations in surface airmass temperature and moisture. Land-use perturbations that accumulated over historical time and greatly accelerated in the last 30 yr may have induced changes from an open, monsoon-type regime with frequent summer storms over the mountains inland to one dominated by closed vertical recirculations where feedback mechanisms favor the loss of storms over the coastal mountains and additional heating of the sea surface temperature during summer. This, in turn, favors Medite...

Identification and chemical characterization of industrial particulate matter sources in Southwest Spain

Abstract A detailed physical and chemical characterization of coarse particulate matter (PM10) and fine particulate matter (PM2.5) in the city of Huelva (in Southwestern Spain) was carried out during 2001 and 2002. To identify the major emission sources with a significant influence on PM10 and PM2.5, a methodology was developed based on the combination of: (1) real-time measurements of levels of PM10, PM2.5, and very fine particulate matter (PM1); (2) chemical characterization and source apportionment analysis of PM10 and PM2.5; and (3) intensive measurements in field campaigns to characterize the emission plumes of several point sources. Annual means of 37, 19, and 16 μg/m3 were obtained for the study period for PM10, PM2.5, and PM1, respectively. High PM episodes, characterized by a very fine grain size distribution, are frequently detected in Huelva mainly in the winter as the result of the impact of the industrial emission plumes on the city. Chemical analysis showed that PM at Huelva is characterized by high PO4 3− and As levels, as expected from the industrial activities. Source apportionment analyses identified a crustal source (36% of PM10 and 31% of PM2.5); a traffic-related source (33% of PM10 and 29% of PM2.5), and a marine aerosol contribution (only in PM10, 4%). In addition, two industrial emission sources were identified in PM10and PM2.5: (1) a petrochemical source, 13% in PM10 and 8% in PM2.5; and (2) a mixed metallurgical-phosphate source, which accounts for 11–12% of PM10 and PM2.5. In PM2.5 a secondary source has been also identified, which contributed to 17% of the mass. A complete characterization of industrial emission plumes during their impact on the ground allowed for the identification of tracer species for specific point sources, such as petrochemical, metallurgic, and fertilizer and phosphate production industries.

Indoor and outdoor air concentrations of BTEX and determinants in a cohort of one-year old children in Valencia, Spain.

BTEX is the commonly used term for a group of toxic compounds (benzene, toluene, ethyl benzene, ortho-xylene and meta- and para-xylene), some of which, most notably benzene, are known carcinogens. The aim of this study is to measure the BTEX levels both inside and outside the homes of 352 one-year old children from the Valencia cohort of the INMA study (Spain) and to analyze the determinants of these levels. Passive samplers were used to measure BTEX levels during a 15day period and a questionnaire was administered to gather information on potentially associated factors (sociodemographics, residential conditions, and lifestyle). The average concentrations of benzene, toluene, ethyl benzene, ortho-xylene, and meta- and para-xylene were 0.9, 3.6, 0.6, 0.6, and 1.0μg/m(3), respectively. On average, the indoor levels of all the compounds were approximately 2.5 times higher than those observed outdoors. Factors associated with higher BTEX concentrations inside the home were being the child of a mother of non-Spanish origin, living in a house that had been painted within the last year, living in an apartment, and not having air conditioning. Higher outdoor concentrations of BTEX depend on the residence being situated in a more urban zone, being located within the city limits, having living in a building with more than one story, residing in an area with a greater frequency of traffic, and the season of the year in which the sample was taken. The data thus obtained provide helpful information not only for implementing measures to reduce exposure to these pollutants, but also for evaluating the relation between such exposure and possible health risks for the children in the cohort.

Outdoor, but not indoor, nitrogen dioxide exposure is associated with persistent cough during the first year of life☆

BACKGROUND AND AIMS Because their lungs and immune system are not completely developed, children are more susceptible to respiratory disease and more vulnerable to ambient pollution. We assessed the relation between prenatal and postnatal nitrogen dioxide (NO(2)) levels and the development of lower respiratory tract infections (LRTI), wheezing and persistent cough during the first year of life. METHODS The study population consisted of 352 children from a birth cohort in Valencia, Spain. Prenatal exposure to NO(2), a marker of traffic related air pollution was measured at 93 sampling sites spread over the study area during four different sampling periods of 7 days each. It was modeled for each residential address through land use regression using the empirical measurements and data from geographic information systems. Postnatal exposure was measured once inside and outside each home using passive samplers for a period of 14 days. Outcomes studied were any episode of LRTI during the childs first year of life diagnosed by a doctor (bronchitis, bronchiolitis or pneumonia), wheezing (defined as whistling sounds coming from the chest), and persistent cough (more than three consecutive weeks). Outcomes and potential confounders were obtained from structured questionnaires. Multiple logistic regression was used to identify associations. RESULTS The cumulative incidence (CI) at first year of life was 30.4% for LRTI (23.0% bronchiolitis, 11.9% bronchitis and 1.4% pneumonia), 26.1% for wheezing and 6.3% for persistent cough. The adjusted odds ratio (95% confidence interval) per 10μg/m(3) increment in postnatal outdoor NO(2) concentration was 1.40 (1.02-1.92) for persistent cough. We also found some pattern of association with LRTI, bronchiolitis, bronchitis, wheezing and persistent cough in different prenatal periods, although it was not statistically significant. CONCLUSIONS Our results indicate that exposure to outdoor, but not indoor, NO(2) during the first year of life increases the risk of persistent cough.