Air quality in Oporto área: comparative analysis

A partir de 1986-1987, on observe une tendance irrégulière de l'augmentation des concentrations moyennes mensuelles d'acidité forte et fumées noires. Les concentrations correspondant aux jours de la semaine sont supérieures à celles obtenues les week-ends et jours fériés, lesquelles mettent en évidence l'apport de l'activité industrielle et du trafic. Aucune corrélation mathématique significative traduisant l'évolution croissante des concentrations moyennes annuelles n'a été mise en évidence. Dans les stations les plus représentatives, les valeurs guides ont été dépassées, les concentrations étant proches de la limite. Bien que nous n'ayons pas enregistré d'épisodes aigus de pollution, l'évolution vérifiée durant la période prise en compte traduit un aggravement de la qualité de l'air. Cette tendance à la hausse est contraire à celle observée dans d'autres pays, où les niveaux d'acidité forte et fumées noires tendent à baisser grâce aux mesures de protection de l'environnement mises en pratique. Les niveaux de monoxyde de carbone, d'oxydes d'azote et d'ozone, observés en 1992 sont plus bas que dans d'autres régions.It was recorded an irregular trend upward for strong acidity and black smoke average monthly concentrations since 1986-1987. Levels in the working days are higher than those monitored in the week-end and days off, which proves the effect of traffic and industrial activities on air quality. It was not possible to establish any overall correlation fiable to express the increase in annual average concentrations. At the most representative stations, the exceedance of guideline values was recorded and concentrations reached values close to the limit. No acute episodes of air pollution were recorded, although the trend patterns monitored show an aggravation of air quality during this period of time. This trend is contrary to the one derived in foreign networks, where strong acidity and black smoke levels have been decreasing in consequence of environmental protection measures put into practice. Carbon monoxyde, nitrogen oxydes and ozone levels measured in 1992 are lower when compared with those monitored in other regions

Study of an ethylic biodiesel integrated process: Raw-materials, reaction optimization and purification methods

No studies are reported on ethylic biodiesel integrated processes, considering raw materials, reaction optimization and product purification. The present study aims to: i) select key variables for experimental optimization of ethanolysis using a virgin vegetable oil; ii) perform an optimization study using a waste oil; and iii) evaluate the effectiveness of water free purification methods. Sunflower oil ethanolysis was conducted at different temperatures (30 - 80 degrees C), catalyst concentrations (0.3 - 2 wt.%), reaction times (0.5 - 4 h) and ethanol: oil molar ratios (2:1 - 12:1). Optimization experiments on waste oil ethanolysis were performed at different temperatures (30 50 C) and ethanol: oil molar ratios (6:1 - 12:1), during 1 h and using 1 wt.% catalyst. Quality parameters were measured according to EN 14214. A cation-exchange resin and a ceramic membrane were evaluated for water-free purification. Regarding sunflower oil ethanolysis, when successful, conversion ranged from 75.2 to 97.7 wt.%. Using both oils under optimized conditions (45 degrees C, 6:1 ethanol:oil molar ratio), a product with a very high purity (>98.0 wt.%) was obtained after water washing purification. The 0.1 mu m ceramic membrane was more effective than the cation-exchange resin, but it was not possible to obtain a good quality product using both methods

Indoor air pollution on nurseries and primary schools: impact on childhood asthma – study protocol

BACKGROUND: Several studies have demonstrated an association between the exposure to indoor air pollution (IAP) and childhood asthma. Evidence is suggesting that several air pollutants may contribute to both exacerbation and development of asthma, but some uncertainty remains concerning the specific causative role of IAP. This paper reports an epidemiologic study aiming to reduce the existing lacks on the association between long-term exposure to pollution mixtures and the development and exacerbation of childhood asthma. METHODS/DESIGN: Based on the implementation of the study in 8 nurseries and 8 primary schools, from which, 2 nurseries and 2 primary schools in sites influenced by traffic and other 2 nurseries and 2 primary schools in background sites at urban and rural areas, the study will analyse the exposure to both urban and rural pollution as well as to traffic emissions (some homes of the children will be included in the study). Furthermore, based on the answers to validated questionnaires (as those used in the International Study of Asthma and Allergies in Childhood - ISAAC) filled in by the parents and on medical exams, the study will assess the prevalence, incidence and exacerbation of asthma, thus considering both short and long-term effects. The approximate number of children in the study will never be less than 600, guaranteeing 80% of study power (significant at a 5% level). DISCUSSION: This study intends to contribute for the understanding of the role of environmental factors, namely indoor air pollution, on asthma considering a risk group of different ages, and for the development of preventive measures, which are considered priority issues by the European Commission, according to the European Environmental Agency and the World Health Organization

Exploratory study on internal recycling of crude glycerol for biodiesel production: Catalyst replacement

The present study evaluated the recycling of crude glycerol as source of catalyst for biodiesel production. For that purpose, two sets of experiments were conducted. In the first set A, biodiesel was synthesized by conventional methanolysis of sunflower oil using NaOH as catalyst at 65 degrees C during 1 h and varying catalyst concentration (0.4-1.2 wt%) or methanol to oil mole ratio (6:1-12:1). The second set (B) was performed by replicating the conditions of set A and considering the use of crude glycerol as source of catalyst. The evaluation of excess methanol and catalyst distribution in the crude products was performed. For both sets of experiments, product yield and quality (viscosity and purity) were determined. Methanol was predominantly in the glycerol phase (54-68%), with negligible effect of variation in catalyst concentration and higher percentages found when higher methanol to oil mole ratios were used, due to a higher polarity of this phase. In most cases, catalyst was predominantly in the crude glycerol (53 wt. % in average) and no clear relation was found between catalyst distribution and the different reaction conditions studied. The results from set A showed a clear influence of catalyst concentration in biodiesel conversion and a minor effect of methanol to oil molar ratio. The best conditions were 6:1 methanol to oil mole ratio and 0.6 wt. % of catalyst leading to a product yield of 95.1 wt. %, a purity of 99.3% and a viscosity of 4.59 ma The second set of experiments, B, showed different trends and variability compared to the first one, and the results indicated that catalyst might be altered during glycerol storage. It was found that the methanol to oil mole ratio affected the reaction conversion, with the highest purity (96.9 wt. %) being obtained when the highest mole ratio was used (12:1), possibly due to the reduced mass transfer limitations. Overall, the results clearly show the potential of using crude glycerol as source of catalyst, avoiding the use of new catalyst and allowing a more sustainable biodiesel production

Films negros en edifícios históricos de Oporto: caracterización y experiencias de limpieza

Los films negros constituyen el principal motivo de las intervenciones de limpieza de fachadas de edificios históricos en la ciudad de Oporto, Portugal, construidos con el granito de Oporto de dos micas, de grano medio a grueso, compuesto de cuarzo, microclina, plagioclasa, muscovita y biotita. Varios estudios realizados sobre la calidad del aire urbano y la deposición de partículas atmosféricas apuntan a un origen antropogénico de estas capas de alteración. El estudio llevado a cabo sobre muestras de films negros del “Hospital de Santo António” revela la presencia de hidrocarburos aromáticos policíclicos (PAH) en cantidades apreciables, detectada por LC-FD (Cromatografía líquida con detector de fluorescencia). El análisis por SEM-EDX (Microscopía electrónica de barrido con microanálisis de rayos X) de estos films muestra que están constituidos por una gran cantidad de partículas de dimensión reducida (que raramente pasan los 10-20 m), asociadas a una matriz de material homogéneo de naturaleza probablemente amorfa. Estas partículas se caracterizan por una gran complejidad mineralógica y morfológica, destacándose partículas ricas en Fe, partículas ricas en Pb, no cristalinas, cenizas volantes esféricas de superficie lisa de Si y Al. Las consecuencias de la presencia de estos compuestos en la superficie de los materiales pétreos son su oscurecimiento. Estas capas de alteración se diferencian de las costras negras debido a su textura, forma, exposición a la acción del agua de la lluvia y composición mineralógica. En consecuencia, las técnicas aplicables a su limpieza son también distintas de las habitualmente usadas para las costras negras. Finalmente, se describen experiencias en operaciones de limpieza llevadas a cabo en edificios de la ciudad de Porto con métodos abrasivos y químicos y se discuten posibilidades tecnológicas y parámetros de control de calidad de las intervenciones.Tópico 6: Patrimonio Urbano de los siglos XVIII al XX. Técnicas de Limpieza y de Conservación

Avaliação das concentrações pré-industriais e actuais de ozono superficial através de séries temporais

A importância do estudo das concentrações de ozono superficial está relacionada com os seusefeitos nocivos quando se atingem níveis elevados deste poluente.Do ozono existente actualmente na troposfera, apenas 20% se deve à intrusão estratosférica,resultando os restantes 80% da formação fotoquímica. No entanto, quando as emissõesantropogénicas ainda não afectavam a qualidade do ar, o ozono troposférico tinha origemfundamentalmente no transporte a partir da estratosfera. Assim, a análise no período pré-industrial, quando a formação fotoquímica era insignificante, fornece informações importantessobre a contribuição da actividade humana no aumento das concentrações superficiais de ozono.Com o objectivo de avaliar essa contribuição na área do Porto, foram comparadas concentraçõesem duas épocas com emissões atmosféricas completamente distintas: um período recente (2002-2003) e um período anterior ao desenvolvimento industrial da região (1861-1897). Foramestudadas as correlações mensais entre a concentração de ozono e a humidade relativa, na erapré-industrial. Foram comparadas as evoluções sazonais e as médias anuais dos dois períodosestudados e avaliados os impactes na saúde comparando as concentrações com os limiareslegislados. A análise comparativa das séries temporais das concentrações de ozono e dastemperaturas máxima e mínima, velocidade do vento e precipitação, permitiu a identificação deciclos de concentrações que foram relacionados com a actividade humana em cada um dosperíodos.Os resultados obtidos permitem concluir que as concentrações superficiais de ozono têm sofridoum elevado aumento desde a era pré-industrial, tendo-se observado um aumento de 250% nomês de Maio. A análise de séries pré-industriais revelou que os ciclos existentes são sazonaisexcluindo a influência das actividades humanas. No período recente, os ciclos de 8 hencontrados nas concentrações de ozono, provam a grande influência dos factoresantropogénicos, sendo os factores meteorológicos responsáveis pelos ciclos de 12 h e 24 hidentificados

Evaluation of Low-Cost Mitigation Measures Implemented to Improve Air Quality in Nursery and Primary Schools

Indoor air pollution mitigation measures are highly important due to the associatedhealth impacts, especially on children, a risk group that spends significant time indoors. Thus,the main goal of the work here reported was the evaluation of mitigation measures implementedin nursery and primary schools to improve air quality. Continuous measurements of CO2, CO,NO2, O3, CH2O, total volatile organic compounds (VOC), PM1, PM2.5, PM10, Total SuspendedParticles (TSP) and radon, as well as temperature and relative humidity were performed in twocampaigns, before and after the implementation of low-cost mitigation measures. Evaluation of thosemitigation measures was performed through the comparison of the concentrations measured in bothcampaigns. Exceedances to the values set by the national legislation and World Health Organization(WHO) were found for PM2.5, PM10, CO2 and CH2O during both indoor air quality campaigns.Temperature and relative humidity values were also above the ranges recommended by AmericanSociety of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). In general, pollutantconcentrations measured after the implementation of low-cost mitigation measures were significantlylower, mainly for CO2. However, mitigation measures were not always sufficient to decrease thepollutants' concentrations till values considered safe to protect human health