Percorrer por autor "Cerqueira, Mário"
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- School air quality and thermal comfort: a multi-pollutant seasonal assessmentPublication . Charres, Isabel; Furst, Leonardo; Vicente, Estela D.; Soares, Marlene; Viegas, Carla; Cervantes, Renata; Pena, Pedro; Cerqueira, Mário; Feliciano, Manuel; Alves, CéliaAs evidence of children's vulnerability to air pollution grows, research on school air quality has increased significantly in the 21st century. Given the complex factors influencing indoor and outdoor air quality in schools, each study offers valuable insights. This study contributes by assessing particulate matter, gaseous pollutants, thermal comfort, and microorganisms in a large school encompassing different education levels over two seasons. The assessment combined passive and continuous sampling using various techniques, including chromatography and estimations of air change and ventilation rates. Classroom ventilation was insufficient to ensure adequate air renewal. During class hours, CO2 concentrations ranged from 760 to 1,118 ppm in winter and from 807 to 1,022 ppm in spring, repeatedly exceeding 1,000 ppm. CO2 and PM10 concentrations were significantly higher during school hours than when the classrooms were empty, indicating the strong influence of school activities. In contrast, PM1 and PM2.5 concentrations were more influenced by external factors, especially outside of school hours. The lack of thermal comfort created an unhealthy environment. Carbonyl concentrations were higher in classrooms (average: 68.8 μg m−3) compared to the schoolyard (3.86 μg m−3), in both seasons. Microbial analysis revealed the presence of fungi with toxigenic potential, with the highest fungal diversity observed in spring. These findings highlight that while some pollutant levels may appear low, they can occasionally reach extremely high levels, even in newer buildings. The novelty of this research lies in demonstrating that, despite recent improvements and numerous studies, significant progress is still needed to ensure healthier school settings.
- Size distribution of polycyclic aromatic hydrocarbons in a roadway tunnel in Lisbon, PortugalPublication . Oliveira, Cesar; Martins, Natércia; Tavares, João; Pio, Casimiro; Cerqueira, Mário; Matos, Manuel; Silva, Hugo; Oliveira, Cristina; Camões, FilomenaAtmospheric aerosols of four aerodynamic size ranges were collected using high volume cascade impactors in an extremely busy roadway tunnel in Lisbon (Portugal). Dust deposited on the tunnel walls and guardrails was also collected. Average particle mass concentrations in the tunnel atmosphere were more than 30 times higher than in the outside urban background air, revealing its origins almost exclusively from fresh vehicle emissions. Most of the aerosol mass was concentrated in submicrometer fractions (65%), and polycyclic aromatic hydrocarbons (PAH) were even more concentrated in the finer particles with an average of 84% of total PAH present in sizes smaller than 0.49 mu m. The most abundant PAH were methylated phenanthrenes, fluoranthene and pyrene. About 46% of the total PAH mass was attributed to lower molecular weight compounds (two and three rings), suggesting a strong influence of diesel vehicle emissions on the production of local particulate PAH. The application of diagnostic ratios confirmed the relevance of this source of PAH in the tunnel ambient air. Deposited dust presented PAH profiles similar to the coarser aerosol size range, in agreement with the predominant origin of coarser aerosol particles from soil dust resuspension and vehicle wear products. (c) 201 1 Elsevier Ltd. All rights reserved.
- Size-segregated chemical composition of aerosol emissions in an urban road tunnel in PortugalPublication . Pio, Casimiro; Mirante, Fátima; Oliveira, Cesar; Matos, Manuel; Caseiro, Alexandre; Oliveira, Cristina; Querol, Xavier; Alves, Célia; Martins, Natércia; Cerqueira, Mário; Camões, Filomena; Silva, Hugo; Plana, FelicianoAn atmospheric aerosol study was performed in 2008 inside an urban road tunnel, in Lisbon, Portugal. Using a high volume impactor, the aerosol was collected into four size fractions (PM0.5, PM0.5-1, PM1-2.5 and PM2.5-10) and analysed for particle mass (PM), organic and elemental carbon (OC and EC), polycyclic aromatic hydrocarbons (PAH), soluble inorganic ions and elemental composition. Three main groups of compounds were discriminated in the tunnel aerosol: carbonaceous, soil component and vehicle mechanical wear. Measurements indicate that Cu can be a good tracer for wear emissions of road traffic. Cu levels correlate strongly with Fe, Mn, Sn and Cr, showing a highly linear constant ratio in all size ranges, suggesting a unique origin through sizes. Ratios of Cu with other elements can be used to source apportion the trace elements present in urban atmospheres, mainly on what concerns coarse aerosol particles. (C) 2013 Elsevier Ltd. All rights reserved.