Browsing by Author "Gama, Carla"
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- Assessing the risk of tropospheric ozone phytotoxic effect on Southern European Mediterranean environments: a review with emphasis on vineyardsPublication . Blanco-Ward, Daniel; Miranda, Ana Isabel; Silveira, Carlos; Ascenso, Ana; Gama, Carla; Monteiro, Alexandra; Lopes, Myriam; Borrego, Carlos S.; Ribeiro, A.C.; Feliciano, Manuel; Castro, João Paulo; Andrade, João Verdial; Barreales, David; Viceto, Carolina; Rocha, Alfredo; Carlos, CristinaTropospheric ozone in Southern Europe has an increasing tendency in association with a greater incidence of warm summers and heatwaves. As there is already much evidence of the negative effects that current ambient ozone has on vegetation, there is a need for consistent risk assessment methods. Ozone plant exposure-based parameters have been used extensively to support decision-making. However, these parameters have been also criticised, as they do not relate with the actual dose of ozone entering the plant. Moreover, in Mediterranean environments, they often overestimate the risk as thresholds are exceeded without corresponding evidence of damaging effects. To overcome these limitations, dose-based approaches were developed. These approaches have a stronger biological basis as they are based on estimates of the amount of ozone molecules that diffuse into the leaf cells through the stomata. However, they have also limitations, as detoxification processes or non-stomatal uptake are not often taken into consideration. This work presents a review regarding ambient ozone effects on vegetation and the indices used to assess phytotoxic risk in southern European Mediterranean plant communities and crops. Emphasis is given to the grapevine as three southern European countries (Spain, Italy and Portugal) are major wine producers concentrating more than 20% of the area under grapevines globally. These countries hold a long winemaking tradition associated to renowned denominations of origin (DOs). Therefore, there is concern regarding climate change as a potential threat to wine typicity in these areas, most of the work focusing on atmospheric variables, bioclimatic and climate change indices only. Results from the DOUROZONE project are presented with the aim to analyse the implications climate change can have in a significant Portuguese wine region such as the Douro Demarcated Region (DDR) including ozone-related indices as a novelty among other more frequently used bioclimatic and climate change indices.
- Atlas Digital DOUROZONEPublication . Monteiro, Alexandra; Rocha, Alfredo; Viceto, Carolina; Ascenso, Ana; Gama, Carla; Blanco-Ward, Daniel; Silveira, Carlos; Ribeiro, A.C.; Castro, João Paulo; Miranda, Ana Isabel; Gonçalves, Luís JorgeUm dos objetivos do projeto DOUROZONE compreendeu a elaboração de um atlas digital para apresentação e divulgação dos seus principais resultados, recorrendo a uma plataforma on-line, de modo a uma melhor e mais eficaz disseminação de informação relativa à avaliação do risco de exposição ao ozono das vinhas da Região Demarcada do Douro, em clima presente e futuro. Este atlas digital – alojado em http://dourozone.web.ua.pt/atlas e com acesso direto através do site do projeto: http://dourozone.web.ua.pt - disponibiliza uma estrutura em árvore, com 3 opções possíveis de visualização, que permitem avaliar a situação do clima presente e o impacte de alterações climáticas (futuro de médio e de longo prazo)
- Avaliação do risco de efeito fitotóxico do ozono troposférico em ambientes Mediterrânicos do sul de Europa: uma revisão com ênfase na cultura da vinhaPublication . Blanco-Ward, Daniel; Miranda, Ana Isabel; Silveira, Carlos; Ascenso, Ana; Gama, Carla; Monteiro, Alexandra; Lopes, Myriam; Borrego, Carlos S.; Ribeiro, A.C.; Feliciano, Manuel; Castro, João Paulo; Andrade, João Verdial; Barreales, David; Viceto, Carolina; Rocha, Alfredo; Carlos, CristinaExiste uma preocupação crescente com os possíveis efeitos das alterações climáticas na indústria vitivinícola em relação à produtividade da vinha e à qualidade do vinho. Um estudo de campo que envolveu medições de ozono superficial, medições meteorológicas e observações fenológicas da vinha foi realizado numa área de produção de vinhos de renome internacional, a Região Demarcada do Douro (RDD). A avaliação dos possíveis efeitos fitotóxicos sobre a qualidade e a produção do vinho foi estimada com base num índice cumulativo de exposição ao ozono (o AOT40) e num parâmetro de dose de ozono fitotóxica (o POD6). Os padrões espaciais desses parâmetros também foram calculados através da aplicação de um modelo químico de transporte atmosférico (CHIMERE) e um modelo de deposição seca de ozono (EMEP). Os principais resultados indicam que a exposição da vinha a níveis de ozono da magnitude dos registados pode causar perdas até 10% na produtividade, porém esta relação requer estudos adicionais para uma mais correta integração das condições ambientais específicas da RDD, especialmente no que diz respeito ao comportamento das castas cultivadas na região, nas metodologias de cálculo destes parâmetros.
- First exploratory study of gaseous pollutants (NO2, SO2, O3, VOCs and carbonyls) in the Luanda metropolitan area by passive monitoringPublication . Alves, Célia; Feliciano, Manuel; Gama, Carla; Vicente, Estela D.; Furst, Leonardo; Leitão, AnabelaAn air quality monitoring campaign for gaseous pollutants using passive sampling techniques was carried out, for the first time, at 25 locations in the metropolitan area of Luanda, Angola, in June 2023. Concentrations of benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes, SO2 and NO2 were generally higher in locations more impacted by traffic. Benzene, SO2 and NO2 levels did not exceed the World Health Organisation guidelines. Ozone concentrations surpassed those documented for other African regions. Higher O3 formation potential values were recorded at heavy-trafficked roads. The top 5 species with potential for ozone formation were m,pxylene, toluene, formaldehyde, propionaldehyde and butyraldehyde. The Mulenvos landfill presented a distinctive behaviour with a very low toluene/benzene ratio (0.47), while values close to 5 were obtained at traffic sites. The maximum levels of α-pinene, D-limonene, formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, butyraldehyde, benzaldehyde, valeraldehyde, hexaldehyde and crotonaldehyde were recorded at the landfill. The formaldehyde/acetaldehyde ratio ranged from 0.40 at the Mulenvos landfill to 3.0, averaging 1.8, which is a typical value for urban atmospheres. Acetaldehyde/propionaldehyde ratios around 0.4–0.6 were found in locations heavily impacted by traffic, whereas values between 0.7 and 1.2 were observed in green residential areas and in places with more rural characteristics. All hazard quotient (HQ) values were in the range from 1 to 10, indicating moderate risk of developing non-cancer diseases. The exception was the Mulenvos landfill for which a HQ of 11 was obtained (high risk). The cancer risks exceeded the tolerable level of 1 × 10-4, with special concern for the landfill and sites most impacted by traffic. A mean lifetime cancer risk of 9 × 10-4 was obtained. The cancer risk was mainly due to naphthalene, which accounted, on average, for 94.6% of the total.
- Investigating ozone episodes in Portugal: a wavelet-based approachPublication . Monteiro, Alexandra; Gouveia, Sónia; Scotto, Manuel González; Lopes, José Fortes; Gama, Carla; Feliciano, Manuel; Miranda, Ana IsabelDuring the summer season, ozone concentrations regularly exceed the legislation limits in the North of Portugal, namely at Douro Norte monitoring station. The origin of such ozone episodes has been widely reported in several studies although uncertainties regarding its origin still remain. This work intends to investigate how the ozone concentrations measured at the Douro Norte nearest stations, located at west and east directions, are related to those measured at Douro Norte by means of coherence and phase transformations methods. The episodes were selected according to the magnitude of the hourly ozone peaks and the occurrence of exceedances of the threshold value at least in two sites. The results point out that 60 % of the selected episodes highlight significant dependence between Douro Norte station and the other two monitoring sites, with different phase signal and a delay range from 2 to 4 h.
- Ozone effects on Douro vineyards under climate changePublication . Ascenso, Ana; Gama, Carla; Silveira, Carlos; Viceto, Carolina; Rocha, Alfredo; Lopes, Myriam; Miranda, Ana IsabelTropospheric ozone (O3) levels in southern Europe have an increasing tendency, in close relation with the higher incidence of hot summers and heatwaves. Given that O3 is one of the most damaging pollutants for vegetation, known to affect productivity and quality of crops, it is necessary to develop more rigorous and consistent methods of risk assessment that consider climate change conditions. Studying the O3 deposition over the Douro Demarcated Region (DDR), which is one of the most productive wine areas in Portugal, and assessing its potential effects under a climate change scenario, was the purpose of this study. To that end, the chemical transport model CHIMERE, with a spatial resolution of 1 km2, fed by meteorological data from the WRF model, was applied for a recent past climate (2003 to 2005) and future mid-term (2049 and 2064) and long-term (2096 and 2097) scenarios. Simulations for future climate were performed considering: (i) only the climate change effect, and (ii) the effect of climate change together with future air pollutant emissions. The assessment of the potential damage in terms of wine productivity and quality (sugar content) was performed through analysis of O3 deposition and the application of concentration–response functions, based on AOT40 values. Modeling results show that a reduction in emission of O3 precursors can successfully decrease AOT40 levels in the DDR, but it is not enough to accomplish the European Commission target value for the protection of vegetation. If the emissions remain constant, the exposure–response functions indicate that, in the long-term, AOT40 levels could worsen wine productivity and quality.