Browsing by Author "Canha, Nuno"
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- Air pollution at an urban traffic tunnel in Lisbon, PortugalPublication . Almeida-Silva, Marina; Canha, Nuno; Freitas, Maria do Carmo; Dung, H. M.; Dionísio, I.In this study, the results of chemical concentrations inside and outside of a Lisbon (Portugal) traffic tunnel were compared, during one week. They were obtained by Instrumental Neutron Activation Analysis (INAA). The tunnel values largely exceed the Air Ambient legislated values and the Pearson Correlations Coefficients point out to soil re-suspension/dispersed road dust (As, Ce, Eu, Hf, Fe, Mo, Sc, Zn), traffic-markers (Ba, Cr), tire wear (Cr, Zn), break wear (Fe, Zn, Ba, Cu, Sb), exhaust and motor oil (Zn) and sea-spray (Br, Na). On all days these elements inside the tunnel were more enriched than outside; significant statistical differences were found for Co (p=0.005), Br (p=0.008), Zn (p=0.01) and Sb (p=0.005), while enrichment factors of As and Sc are statistically identical. The highest values were found for As, Br, Zn and Sb, for both inside and outside the tunnel.
- Assessment of aerosol emission sources in a traffic site combining on-line and off-line measurementsPublication . Coutinho, J. T.; Canha, Nuno; Galinha, C.; Martins, V.; Faria, Tiago; Almeida-Silva, Marina; Lage, J.; Rigler, M.; Mocnik, G.; Diapouli, E.; Eleftheriadis, K.; Almeida, Susana MartaIn urban areas, evidence from epidemiological and experimental studies show that traffic-related air pollution has adverse effects on respiratory and cardiovascular systems. Urban air pollution accounts for 3% of mortality from cardiopulmonary disease and 1% of mortality from acute respiratory infections in children under 5 years, worldwide. Therefore, disease and mortality associated with vehicle emissions represent a substantial challenge in public health. Source apportionment, using receptor models, is an essential tool to support the implementation of the European and Member States legislation on air quality and principally to reduce the impact of exposure to Air Particulate Matter (PM) on human health. This work was developed in the framework of the Interreg Med REMEDIO project and aims to assess the aerosol emission sources in an urban traffic site, located in the outskirts of Lisbon.
- Assessment of particulate matter levels and sources in a street canyon at Loures, Portugal: a case study of the REMEDIO projectPublication . Almeida-Silva, Marina; Canha, Nuno; Vogado, Filipa; Baptista, P. C.; Faria, A. V.; Faria, T.; Coutinho, J. T.; Alves, C.; Almeida, S. M.Air quality in urban environments is directly related to structural aspects of streets and traffic variables, justifying the need for local assessments. This information is crucial to obtain accurate and reliable statistical modeling of the implementation of different mitigation scenarios aiming to improve the local air quality management. The present study intended to assess temporal trends of particulate matter levels in a street canyon of the urban area of Moscavide (Loures, Portugal) for one-month in autumn of 2016. Moreover, fine and coarse particles were characterized by their carbonaceous and elemental contents in order to identify the main pollution sources affecting the study area. Particle concentration peaks were observed during the daytime and were associated with traffic intensity due to commuting. During the studied period, no exceedances of the limit values set by the European legislation were registered. The natural sources sea salt and mineral dust contributed, on average, to 6 and 8% of PM10 levels. The Fe/Cu ratios indicated the contribution of wear emissions from road traffic. Enrichment of anthropogenic elements in PM was found. Several traffic markers were identified from specific correlations between elements (good: Cu–Mn, Cu–Pb; moderate: Cu–Zn, Mn–Zn, Pb–Zn), highlighting the contribution of local traffic to PM levels. This information is valuable to understand the possible health effects of particulate matter levels on citizens due to their exposure and to establish a reference scenario with which the future implementation of mitigation measures targeting local traffic can be compared to assess improvements in air quality in the studied street canyon.
- Bioburden in sleeping environments from Portuguese dwellingsPublication . Viegas, Carla; Dias, Marta; Monteiro, Ana; Faria, Tiago; Lage, Joana; Carolino, Elisabete; Caetano, Liliana Aranha; Gomes, Anita Q.; Almeida, Susana Marta; Verde, Sandra Cabo; Belo, Joana; Canha, NunoA wider characterization of indoor air quality during sleep is still lacking in the literature. This study intends to assess bioburden before and after sleeping periods in Portuguese dwellings through active methods (air sampling) coupled with passive methods, such as electrostatic dust cloths (EDC); and investigate associations between before and after sleeping and bioburden. In addition, and driven by the lack of information regarding fungi azole-resistance in Portuguese dwellings, a screening with supplemented media was also performed. The most prevalent genera of airborne bacteria identified in the indoor air of the bedrooms were Micrococcus (41%), Staphylococcus (15%) and Neisseria (9%). The major indoor bacterial species isolated in all ten studied bedrooms were Micrococcus luteus (30%), Staphylococcus aureus (13%) and Micrococcus varians (11%). Our results highlight that our bodies are the source of the majority of the bacteria found in the indoor air of our homes. Regarding air fungal contamination, Chrysosporium spp. presented the highest prevalence both in after the sleeping period (40.8%) and before the sleeping period (28.8%) followed by Penicillium spp. (23.47% morning; 23.6% night) and Chrysonilia spp. (12.4% morning; 20.3% night). Several Aspergillus sections were identified in air and EDC samples. However, none of the fungal species/strains (Aspergillus sections Fumigati, Flavi, Nidulantes and Circumdati) were amplified by qPCR in the analyzed EDC. The correlations observed suggest reduced susceptibility to antifungal drugs of some fungal species found in sleeping environments. Toxigenic fungal species and indicators of harmful fungal contamination were observed in sleeping environments.
- Burn wood influence on outdoor air quality in a small village: Foros de Arrão, PortugalPublication . Canha, Nuno; Freitas, Maria do Carmo; Almeida-Silva, Marina; Almeida, Susana Marta; Dung, H. M.; Dionísio, I.; Cardoso, J.; Pio, C. A.; Caseiro, A.; Verburg, T. G.; Wolterbeek, H. Th.One Plus Sequential Air Sampler—Partisol was placed in a small village (Foros de Arrão) in central Portugal to collect PM10 (particles with an aerodynamic diameter below 10 μm), during the winter period for 3 months (December 2009–March 2010). Particles masses were gravimetrically determined and the filters were analyzed by instrumental neutron activation analysis to assess their chemical composition. The water-soluble ion compositions of the collected particles were determined by Ion-exchange Chromatography. Principal component analysis was applied to the data set of chemical elements and soluble ions to assess the main sources of the air pollutants. The use of both analytical techniques provided information about elemental solubility, such as for potassium, which was important to differentiate sources.
- Compliance of indoor air quality during sleep with legislation and guidelines: a case study of Lisbon dwellingsPublication . Canha, Nuno; Alves, Ana Carolina; Marta, Catarina Simão; Lage, Joana; Belo, Joana; Faria, Tiago; Cabo-Verde, Sandra; Viegas, Carla; Alves, Célia; Almeida, Susana MartaThis study aimed to provide a comprehensive characterization of the indoor air quality during the sleeping period of 10 couples at Lisbon dwellings, using a multi-pollutant approach, and to understand how the compliance with legislation and guidelines was to assure good indoor air quality. The assessment of indoor air quality was conducted in the cold season using real-time monitors during the sleeping period for comfort parameters (temperature and relative humidity) and air pollutants (carbon dioxide - CO2, carbon monoxide - CO, formaldehyde - CH2O, total volatile organic compounds - VOCs, and particulate matter - PM2.5 and PM10), together with an active sampling of bioaerosols (fungi and bacteria) before and after the sleeping period. Lower compliance (less than 50% of the cases) with the Portuguese legislation was found for temperature, CO2 (3440 ± 1610 mg m-3), VOCs (1.79 ± 0.99 mg m-3), and both bioaerosol types. In 70% of the cases, PM2.5 (15.3 ± 9.1 μg m-3) exceeded the WHO guideline of 10 μg m-3. All bedrooms presented air change rates above the recommended minimum value of 0.7 h-1, highlighting that good indoor air quality during sleep is not guaranteed.
- Fungi, bacteria and pollens seasonally quantified at 3 basic schools in Lisbon: evaluation of ventilation needPublication . Canha, Nuno; Ribeiro, Marcos; Freitas, Maria do Carmo; Almeida-Silva, Marina; Almeida, Susana Marta; Cabo-Verde, Sandra; Wolterbeek, H. Th.Nowadays, most individuals spend about 80% of their time indoor and, consequently, the exposure to the indoor environment becomes more relevant than to the outdoor one. Children spend most of their time at home and at school and evaluations of their indoor environment are important for the time-weighted exposure. Due to their airways still in development, children are a sensitive group with higher risk than adults. Larger impact in health and educational performance of children demand indoor air quality studies of schools. The aim of this study was to assess the children exposure to bioaerosols. A methodology based upon passive sampling was applied to evaluate fungi, bacteria and pollens; its procedures and applicability was optimized. An indoor air study by passive sampling represents an easier and cheaper method when comparing with the use of automatic active samplers. Furthermore, it is possible to achieve important quality information without interfering in the classroom activities. The study was conducted in three schools, representative of different environments in the Lisbon urban area, at three different periods of the year to obtain a seasonal variation, to estimate the variability through the city and to understand the underneath causes. Fungi and bacteria were collected indoor and outdoor of the classrooms to determine the indoor/outdoor ratios and to assess the level of outdoor contamination upon the indoor environment. The children's exposure to pollen grains inside the classrooms was also assessed.
- How is indoor air quality during sleep? A review of field studiesPublication . Canha, Nuno; Teixeira, Catarina; Figueira, Mónica; Correia, CarolinaThis review aimed to provide an overview of the characterization of indoor air quality (IAQ) during the sleeping period, based only on real-life conditions’ studies where, at least, one air pollutant was considered. Despite the consensual complexity of indoor air, when focusing on sleeping environments, the available scientific literature is still scarce and falls to provide a multipollutant’ characterization of the air-breathing during sleep. This review, following PRISMA’s approach, identified a total of 22 studies that provided insights into how IAQ is during the sleeping period in real life conditions. Most of the studies focused on carbon dioxide (77%), followed by particles (PM2.5, PM10, and ultrafine), and only 18% of the studies focused on pollutants such as carbon monoxide, volatile organic compounds, and formaldehyde. Despite the high heterogeneity between studies (regarding the geographical area, type of surrounding environments, the season of the year, type of dwelling, bedrooms’ ventilation, number of occupants), several air pollutants showed exceedances of the limit values established by guidelines or legislation, indicating that an effort should be made in order to minimize human exposure to air pollutants. For instance, when considering the air quality guideline of the World Health Organisation of 10 µg·m−3 for PM2.5, 86% of studies that focused on this pollutant registered levels above this threshold. Considering that people spend one-third of their day sleeping, exposure during this period may have a significant impact on the daily integrated human exposure, due to the higher amount of exposure time, even if this environment is characterized by lower pollutants’ levels. Improving the current knowledge of air pollutants levels during sleep in different settings, as well as in different countries, will allow improving the accuracy of exposure assessments and will also allow understanding their main drivers and how to tackle them.
- Impacto da qualidade do ar interior nos parâmetros cardiorrespiratórios durante o sonoPublication . Belo, Joana; Picado, M.; Lage, J.; Faria, Tiago; Macedo, Paula; Meira e Cruz, M.; Canha, Nuno; Cabo Verde, Sandra; Alves, C.; Viegas, Carla; Almeida, Susana MartaOs efeitos da poluição ambiental na saúde estão amplamente documentados, havendo evidências dos efeitos a longo e a curto prazo que se relacionam com maiores taxas de morbilidade e mortalidade, principalmente de causa cardiovascular e respiratória. No entanto, as evidências sobre os efeitos da qualidade do ar interior (QAI) no sono são ainda limitadas. Durante o sono NREM e REM existem diferentes mediadores ao nível da função autonómica, podendo conduzir a características distintas ao nível da frequência cardíaca (FC), respiratória (FR) e pressão arterial. O presente estudo tem o objetivo de avaliar a existência de correlações entre determinados parâmetros cardiorrespiratórios durante o sono e a QAI.
- Indoor air quality assessment in grocery storesPublication . Baptista, Teresa; Almeida-Silva, M.; Silva, Dário; Diogo, Carlos; Canha, NunoIndoor Air Quality (IAQ) is a public and occupational health concern, as we are exposed to air pollutants daily given that we spend a great amount of our time in indoor environments. IAQ can be affected by numerous factors, from outdoor pollutants that get indoors through ventilation to building materials, furnishings, and activities carried by the building occupants. Exposure to air pollutants has been linked to a panoply of adverse effects on our health, well-being, and performance. The aim of this study was to assess the IAQ in grocery stores (GSs) in the municipality of Cascais in the Lisbon metropolitan area (Portugal) to characterize the workers’ occupational exposure to air pollutants. The study was conducted in 13 small “family” grocery stores. The IAQ monitoring campaign was conducted using low-cost sensor technologies and focused on several parameters, namely: carbon dioxide (CO2), volatile organic compounds (VOCs), particulate matter (PM10 and PM2.5), temperature (T), relative humidity (RH). Overall, the IAQ of the studied GSs complied with Portuguese legislation, except for PM2.5, where 23% of GSs presented levels above the established limit value. The mean inhaled dose of workers during a workday was estimated to be 157.7 ± 57.2 μg for PM2.5 and 165.8 ± 56.0 μg for PM10. The IAQ assessment allowed the identification of the best strategies to improve worker experience in indoor workplace environments.
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