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Santa Cruz de Tenerife, Spain

Pey J.,CSIC - Institute of Environmental Assessment And Water Research | Alastuey A.,CSIC - Institute of Environmental Assessment And Water Research | Querol X.,CSIC - Institute of Environmental Assessment And Water Research | Rodriguez S.,Izana Atmospheric Research Center
Atmospheric Environment

Different monitoring parameters (PM mass concentrations, number-size distribution, black carbon, gaseous pollutants, and chemical composition, among others) are currently used in air quality studies. Urban aerosols are the result of several sources and atmospheric processes, which suggests that a single monitoring technique is insufficient to quantitatively evaluate all of them.This study assesses the suitability of a number of monitoring techniques (PM mass concentrations, number and size distribution of ultra-fine particles, levels of gaseous pollutants, and a complete chemical characterization of PM10 and PM2.5) by examining the response of those techniques to the different emission sources and/or atmospheric processes affecting an urban Mediterranean area (Barcelona, NE Spain).The results of this work reveal that the PM mass, the number concentration and the chemical composition give different, but complementary, information. Whereas the mineral matter, a key atmospheric aerosol component across the Mediterranean, is not properly quantitatively assessed by measuring sub-micrometric particles, the monitoring of the number concentration is indispensable to interpret the origin of specific aerosol episodes. Furthermore, the chemical composition yields very relevant information to deduce the causes of specific pollution episodes.The number concentration of ultra-fine particles in urban areas is strongly dependent upon vehicle exhaust emissions, which may cause adverse health impacts. Moreover, urban Mediterranean environments are favourable to produce nucleation-mode particles (<20 nm) with photochemical origin. In those cases, these particles are expected to be of high solubility and consequently their toxicity may differ from that of traffic-generated ultra-fine particles. Thus, the use of a single monitoring parameter to evaluate the health effects seems to be not enough. © 2010 Elsevier Ltd. Source

Rodriguez S.,Izana Atmospheric Research Center | Alastuey A.,CSIC - Institute of Environmental Assessment And Water Research | Querol X.,CSIC - Institute of Environmental Assessment And Water Research
Aeolian Research

Desert dust emitted and transported to distant regions influence on the climate, biogeochemistry and air quality of our planet. Long term (multi-decadal) measurements of aerosol dust with in situ characterization techniques are crucial for understanding the interactions of dust with the Earth system. We reviewed the programs which have been performing such long term dust monitoring. First long term observations started in the North Atlantic during the 1960s. Although dust programs rapidly expanded during the 1980s and 1990s, mostly across the Pacific and Atlantic oceans, only a few sites that have been active in the last 20-30. years continue operative nowadays. We reviewed the techniques that are available for in situ aerosol dust characterization. Techniques for long term measurement of mass concentration, size distribution, bulk composition, optical properties are nowadays available. Other techniques that are not regularly used in (or designed for) long term programs are also described; these may be incorporated into long term programs in specific periods (e.g. dust season on a year-to-year basis). Their implementation in long term programs allow us to study potential changes in the sources of some key minerals linked to changes in the strength and location of dust sources, and/or the mixing state of dust with pollutants related to the evolution of anthropogenic emissions. Given that some of these methods are not specifically designed for dust, some considerations should be addressed when the techniques are used for aerosol dust measurements. Accuracy, sources of errors, corrections and features of dust measurements are reviewed. © 2012 Elsevier B.V. Source

Dall'Osto M.,CSIC - Institute of Environmental Assessment And Water Research | Beddows D.C.S.,University of Birmingham | Pey J.,CSIC - Institute of Environmental Assessment And Water Research | Rodriguez S.,University of Huelva | And 5 more authors.
Atmospheric Chemistry and Physics

Differential mobility particle sizer (DMPS) aerosol concentrations (N13-800) were collected over a one-year-period (2004) at an urban background site in Barcelona, North-Eastern Spain. Quantitative contributions to particle number concentrations of the nucleation (33-39%), Aitken (39-49%) and accumulation mode (18-22%) were estimated. We examined the source and time variability of atmospheric aerosol particles by using both K-means clustering and Positive Matrix Factorization (PMF) analysis. Performing clustering analysis on hourly size distributions, nine K-means DMPS clusters were identified and, by directional association, diurnal variation and relationship to meteorological and pollution variables, four typical aerosol size distribution scenarios were identified: traffic (69% of the time), dilution (15% of the time), summer background conditions (4% of the time) and regional pollution (12% of the time). According to the results of PMF, vehicle exhausts are estimated to contribute at least to 62-66% of the total particle number concentration, with a slightly higher proportion distributed towards the nucleation mode (34%) relative to the Aitken mode (28-32%). Photochemically induced nucleation particles make only a small contribution to the total particle number concentration (2-3% of the total), although only particles larger than 13 nm were considered in this study. Overall the combination of the two statistical methods is successful at separating components and quantifying relative contributions to the particle number population. © 2012 Author(s). Source

Martin J.L.,Canary Islands Agency for Climate Change and Sustainable Development | Bethencourt J.,Canary Islands Agency for Climate Change and Sustainable Development | Cuevas-Agullo E.,Izana Atmospheric Research Center
Climatic Change

Temperature variation is studied at different altitudes and orientation on the island of Tenerife, according to the trends in the mean, maximum and minimum at 21 meteorological stations. Reference series are obtained by sectors, along with a representative overall series for Tenerife, in which temperature shows a statistically significant growth trend of 0.09 ± 0.04°C/decade since 1944. Night-time temperatures have risen most (0.17°C ± 0.04°C/decade), while by day they have been more stable. Consequently, the diurnal temperature range between day and night has narrowed. By regions, warming has been much more intense in the high mountains than the other sectors below the inversion layer between 600 and 1,400 m altitude, and progressively milder towards the coast. The temperature rise on the windward (north-northeast) slopes is greater than on the leeward side and could be related to the increase in cloudiness on the northern side. The general warming of the island is less than in continental areas at between 24 and 44°N, being closer to the sea surface temperature in the same area. This is probably explained largely by the insular conditions. In fact warming is more evident in the high mountains (0.14 ± 0.07°C/decade), where the tempering effect of the ocean and the impact of changes in the stratocumulus is weaker, being similar to the mean continental values in the northern hemisphere. © 2012 Springer Science+Business Media B.V. Source

Cuevas E.,Izana Atmospheric Research Center | Gonzalez Y.,Izana Atmospheric Research Center | Rodriguez S.,Izana Atmospheric Research Center | Guerra J.C.,University of La Laguna | And 6 more authors.
Atmospheric Chemistry and Physics

An analysis of the 22-yr ozone (O3) series (1988-2009) at the subtropical high mountain Izaña∼station (IZO; 2373 m a.s.l.), representative of free troposphere (FT) conditions, is presented. Diurnal and seasonal O3 variations as well as the O3 trend (0.19 ± 0.05 % yr-1 or 0.09 ppbv yr-1), are assessed. A climatology of O 3 transport pathways using backward trajectories shows that higher O3 values are associated with air masses travelling above 4 km altitude from North America and North Atlantic Ocean, while low O3 is transported from the Saharan continental boundary layer (CBL). O3 data have been compared with PM10, 210Pb, 7Be, potential vorticity (PV) and carbon monoxide (CO). A clear negative logarithmic relationship was observed between PM10 and surface O3 for all seasons. A similar relationship was found between O3 and 210Pb. The highest daily O3 values (90th percentile) are observed in spring and in the first half of summer time. A positive correlation between O3 and PV, and between O 3 and 7Be is found throughout the year, indicating that relatively high surface O3 values at IZO originate from the middle and upper troposphere. We find a good correlation between O3 and CO in winter, supporting the hypothesis of long-range transport of photochemically generated O3 from North America. Aged air masses, in combination with sporadic inputs from the upper troposphere, are observed in spring, summer and autumn. In summer time high O3 values seem to be the result of stratosphere-to-troposphere (STT) exchange processes in regions neighbouring the Canary Islands. Since 1995-1996, the North Atlantic Oscillation has changed from a predominantly high positive phase to alternating between negative, neutral or positive phases. This change results in an increased flow of the westerlies in the mid-latitude and subtropical North Atlantic, thus favouring the transport of O3 and its precursors from North America, and a higher frequency of storms over North Atlantic, with a likely higher incidence of STT processes in mid-latitudes. These processes lead to an increase of tropospheric O3 in the subtropical North Atlantic region after 1996 that has been reflected in surface O3 records at IZO. © 2013 Author(s). Source

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