This paper explores the potential of a vertical garden to function as an active evaporative cooling air conditioning unit. It builds on previous work by Davis, Ramirez and Vallejo [1]. This study shows the results of a full scale, building incorporated vertical garden that measured 1.5 m wide by 2.8 m high. Air flowed behind the garden substrate, where it was cooled and humidified as it flowed down the back of the garden through its contact with the humid surface. The experimental results were compared to the mathematical model developed by Davis and Hirmer [2]. Overall, it was suspected that variations in ambient temperatures during the measurements taking process had a major influence on the results. In taking the data considered most reliable into account however, the results of the mathematical model end experimental data were within 0.44 °C. The results indicate that such gardens show great promise for building climate control, but where further research is needed in order to mitigate the influence of fluctuations in ambient temperatures.

Quito is an Andean city with 2.7 million inhabitants that regularly exceeds the WHO air quality guidelines for O3, SO2, PM2.5, and PM10. Within the historic center in an area of 920.000 m2, only 4% is green space. However, 14.000 m2 of vertical walls exist that could potentially host vertical gardens. The present study evaluates the ability of four vertical gardens to improve air quality and quantifies the area of viable spaces to host vertical gardens in the Historic Center. The air quality was monitored with continuous measuring systems near each vertical garden and in areas outside the area of influence. The capacity for retention of gaseous emissions from an internal combustion engine in an active garden was also evaluated. The results were a mixture of advantages and uncovering possible myths: a) the presence of vertical gardens causes a significant decrease in O3 (up to 99%), NO2 (up to 80%), SO2 (up to 83%), PM2.5 (up to 79%) and PM10 (up to 85%); b) however, a poor choice of plant species in vertical gardens may increase the formation of O3; and c) in the case of exposing an active vertical garden to emissions injected directly into the garden by a combustion engine, the particle size distribution influences its removal, being more efficient with a size greater than 4 smaller diameters.

En las últimas décadas, el desarrollo económico de Quito ha venido acompañado con un deterioro en su calidad del aire, principalmente por el aumento progresivo de su flota vehicular. Ante ello, la autoridad ambiental de la zona, registra concentraciones que superan las normas nacionales e internacionales de calidad del aire en los parámetros de PM10, PM2,5 y O3. Ante este escenario, la implementación de infraestructura verde urbana (IVU) emerge como una alternativa para el mejoramiento de la calidad del aire en microambientes, sin embargo sus costos limitan su aplicación. El trabajo presentado, estima, mediante la metodología AP-HRA, los efectos económicos y en salud pública que se obtendría producto de una implementación agresiva de IVU en ocho parroquias de Quito. Los resultados generados son alentadores dado que una reducción del 30 % en PM10 y O3 y 1 % en PM2,5, podría evitar 190 muertes anualmente en la zona de estudio, con un beneficio económico para la sociedad de 139,7 millones de USD. Las estimaciones presentadas, pueden servir de herramienta para los tomadores de decisión con el fin de instrumentar políticas públicas que promuevan la implementación de IVU en espacios públicos y privados.

As part of a transdisciplinary study on the benefits of vertical gardens in Quito (Ecuador), social research was carried out to determine people's perceptions and level of understanding of living walls. The four gardens studied were on the campus of the Pontifical Catholic University of Ecuador (semi-public), in the San Blas Plaza (public), in the Governmental Financial Platform (semi-public), and in the private offices of an architecture firm (private). The research was organized into two primary phases; the first involved carrying out observations of each of the four vertical gardens. The observations led to the characterization of the immediate surroundings of the gardens, an understanding of accessibility (particularly for people with disabilities and security-related limitations), as well as of the number of people who passed through the space and the type of interactions they had with the garden. During the second phase, a total of 57 interviews were carried out with people in the areas surrounding each of the vertical gardens. The interviews identified basic demographic information about the respondents, how they define vertical gardens, the type, and frequency of their interactions with the specific garden of study, and their perceptions of the benefits and drawbacks of vertical gardens. The information from the interviews was processed to identify key trends related to each garden, as well as identify trends across the four gardens. The results revealed varying levels of understanding of vertical gardens, the influence of esthetics on people's perceptions, and finally ideas around the benefits and drawbacks of vertical gardens. The conclusions demonstrated a gap between social perceptions of vertical gardens, particularly in public spaces, and the gardens' potential ecological and air quality contributions to the city.

El presente estudio muestra el rendimiento de un prototipo de jardín vertical activo “CMMC” como unidad de enfriamiento y filtro para mejorar la calidad del aire interior y exterior. El comportamiento de jardines verticales fue analizado mediante tres casos de estudio. El jardín vertical activo CMMC enfrió el aire en un promedio de 8,1 °C con una capacidad de enfriamiento promedio de 682,8 W. Incluyendo los efectos del preenfriamiento en la entrada del jardín, el jardín enfrió el aire 14,3 °C en promedio, con una capacidad de enfriamiento promedio de 1.203,2 W. En el tercer caso, se monitoreó la calidad del aire en las cercanías y en sitios sin la influencia del jardín vertical, logrando una disminución de ozono (75%), dióxido de nitrógeno (44%) y partículas PM2,5 (79%) y PM10 (85%). Los resultados fueron concluyentes: el jardín activo CMMC presenta mejoras de calidad del aire superiores respecto a los jardines pasivos. El fenómeno de absorción de contaminantes marca una propuesta para la mejora de la calidad del aire en zonas críticas de contaminación en el Centro Histórico de Quito.

Purpose: Vertical gardens offer multiple benefits in urban environments, including passive cooling services. Previous research explored the use of “active vertical gardens” as potential evaporative air-cooling units by developing a mathematical model based on the FAO-56 Penman Monteith equation. Further research showed that active vertical gardens function best by creating an airflow in the cavity behind the garden such that air is cooled by flowing over the water-saturated garden substrate. The purpose of this paper is to improve the quantification of active vertical garden performance. Design/methodology/approach: A building-incorporated vertical garden was built in Quito, Ecuador, with an air inlet at the top of the garden, an air cavity behind the garden and where air was expelled from the base. Measurements were made of air temperature, humidity and velocity at the air inlet and outlet. Findings: The active vertical garden cooled the air by an average of 8.1 °C with an average cooling capacity of 682.8 W. Including the effects of pre-cooling at the garden inlet, the garden cooled the air by an average of 14.3 °C with an average cooling capacity of 1,203.2 W. Originality/value: The results are promising and support the potential for active vertical gardens to be incorporated into building services and climate control.

Se estudió la contaminación del aire a filo de calle en el Centro Histórico de Quito (DMQ) en un punto de alto flujo vehicular mediante el monitoreo continuo de gases y material particulado entre el 5 y 12 de abril de 2018. Se obtuvieron los perfiles horarios de las concentraciones de contaminantes y se pudo explicar su comportamiento. Las mediciones en el estudio no sobrepasaron los límites permisibles nacionales ni internacionales de calidad del aire; sin embargo, se observaron picos anómalos en el caso del dióxido de azufre. Se evaluó la correlación cruzada de las series de tiempo entre los datos reportados por estaciones regionales de la Secretaria de Ambiente del DMQ y los datos obtenidos en este estudio, hallándose que el monóxido de carbono presenta una mayor concentración a filo de calle. Al realizar el análisis de componentes principales (ACP) se determinó varios contaminantes correlacionados, lo que corroboran sus ciclos de formación y demuestran la influencia de factores meteorológicos en la contaminación de aire a filo de calle. Finalmente se determinó que las concentraciones de PM10 en aire interior son mayores a lo registrado en aire exterior en el sitio de muestreo.

Quito is an Andean city with 2.7 million inhabitants that regularly exceeds the WHO air quality guidelines for O3, SO2, PM2.5, and PM10. Within the historic center in an area of 920.000 m2, only 4% is green space. However, 14.000 m2 of vertical walls exist that could potentially host vertical gardens. The present study evaluates the ability of four vertical gardens to improve air quality and quantifies the area of viable spaces to host vertical gardens in the Historic Center. The air quality was monitored with continuous measuring systems near each vertical garden and in areas outside the area of influence. The capacity for retention of gaseous emissions from an internal combustion engine in an active garden was also evaluated. The results were a mixture of advantages and uncovering possible myths: A) the presence of vertical gardens causes a significant decrease in O3 (up to 99%), NO2 (up to 80%), SO2 (up to 83%), PM2.5 (up to 79%) and PM10 (up to 85%); b) however, a poor choice of plant species in vertical gardens may increase the formation of O3; and c) in the case of exposing an active vertical garden to emissions injected directly into the garden by a combustion engine, the particle size distribution influences its removal, being more efficient with a size greater than 4 um but not effective for smaller diameters.