Browsing by Subject "Urban environment"

Now showing 1 - 3 of 3
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    Effect of the passive natural ventilation on the bioaerosol in a small room
    (Elsevier, 2021-10-13) Núñez, Andrés; García, Ana M.; Genética y Microbiología
    Natural passive ventilation (windows opening) is frequently used in many houses and old buildings to renovate the air, remove unpleasant odors and dust, and reduce the physicochemical pollutants indoor. However, little is known about the effect on biological particles such as pollen grains and fungal spores (both allergenic) or bacteria (potentially infectious and pathogenic). In the present research, the bioaerosols composition in a small room naturally ventilated was analyzed by high-throughput DNA sequencing. Pollen grains were the most abundant particles outdoors while microbial phyla Actinobacteria, Firmicutes, Proteobacteria and Ascomycota were predominant indoors. The main divergences in bioaerosols between indoor and outdoor environments were caused by the different abundance of the biological particles rather than the different taxa composition. Keeping the window open for 2 h did not change significantly the microbial community present indoors, although there was a tendency to mix the components of both environments. The abundance of human-related and potentially harmful microorganisms was higher indoors and was not remarkably affected by natural ventilation. In our study, natural ventilation through window opening had a poor effect on removing these microorganisms from the atmosphere indoor, suggesting that additional mechanisms such as air filtering systems would be required in order to improve the air quality of these environments from a microbiological point of view.
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    The aerobiome in a hospital environment: characterization, seasonal tendencies and the effect of window opening ventilation
    (Elsevier, 2023-01-16) Núñez, Andrés; García, Ana M.; Genética y Microbiología
    The urban atmosphere carries biological particles (bioaerosols) that may cause several diseases and allergies. These bioaerosols infiltrate and mix with those present inside the buildings, including hospitals. However, little is known about the behavior of these particles around health facilities. Here, we described the bioaerosols composition of an urban hospital indoor and outdoor at two different periods (winter and summer) using DNA sequencing. We observed that the seasonality and composition of the bioaerosols outdoor was also displayed indoor, and, in some cases, the taxa showed different trends depending on the season. Pathogenic species of bacteria and fungi were found indoors at low levels but also outdoors, being mostly environmental species, which would reject the idea that hospitals may be acting as a source of emission via aerosols. Skin-related bacteria were the most prevalent group related to human microbiome, being more abundant indoors. Air temperature was the principal factor affecting the bioaerosols composition in the samples but, in general, meteorological parameters outdoors were poor descriptors of the bioaerosols indoors. Similarly, the concentrations of the main indoor air pollutants did not correlate with microbial abundances. Globally, natural ventilation through a window opening did not significantly alter the composition of the bioaerosols indoor.
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    Wind and turbulence relationship with NO2 in an urban environment: a fine-scale observational analysis
    (Elsevier, 2023-08-31) Román-Cascón, Carlos; Yagüe, Carlos; Ortiz-Corral, Pablo; Serrano, Encarna; Sánchez, Beatriz; Sastre, Mariano; Maqueda, Gregorio; Alonso-Blanco, Elizabeth; Artiñano, Begoña; Gómez-Moreno, Francisco J.; Díaz-Ramiro, Elias; Fernández, Jesús; Martilli, Alberto; García, Ana M.; Núñez, Andrés; Cordero, José María; Narros, Adolfo; Borge, Rafael; Genética y Microbiología
    It is well known that meteorology plays an important role in the diurnal evolution of pollutants, especially those variables related to atmospheric dispersion. Most studies typically relate the concentration of some pollutants with wind speed from conventional anemometers; however, the use of turbulence variables is less common, in part because the needed instruments are not so typical in standard air-quality stations. In this work, we compare the wind-NO2 relationship with the turbulence-NO2 one using observational data from two field campaigns developed in Madrid (winter and summer). The turbulence data comes from two sonic anemometers deployed at different locations: one close to the street and the other at the top of a nearby tall building. The results indicate that the turbulent variables correlate better with the pollutant concentration than the wind speed when using data from the street sonic, while the contrary is found when using the terrace sonic. These data are also used to perform a fine-scale analysis of the turbulent diffusion-NO2 behaviour during a very-stable period in winter, when the turbulence typically shows a decrease in the evening transition, causing the highestNO2 concentrations. Conversely, under these conditions, the formation of thermally-driven winds is also favoured later in the night, which favours the pollutant dispersion and cleaning of the air. The important role of these dynamical processes on the NO2 evolution highlights the importance of the correct understanding of small-scale atmospheric processes to understand their relationship with the concentration of pollutants.