Greening Our Cities: How Vertical Greenery Systems (VGS) Help Capture Carbon and Improve Indoor Health

Dr. Jasmin Ghazalli

                                           Photo source: Adobe Express

Due to climate change, increasing temperatures, and urban stress, designers are investigating innovative approaches to reintroduce nature into the urban fabric. Green infrastructures such as green roofs and vertical greenery systems (VGS) is a robust and interesting solution that aids in increasing green coverage. As urban areas become increasingly hot, busy, and congested, vertical greenery provides a sustainable method for greenery expansion—vertically rather than horizontally.  These technologies enhance urban environments, improve air quality, and provide more favorable conditions for living and working.

Carbon capture is an essential element of climate change mitigation, as it directly diminishes atmospheric carbon dioxide (COâ‚‚). Carbon capture reduces COâ‚‚ concentrations, therefore decelerating temperature increases, alleviating severe weather phenomena, and safeguarding at-risk ecosystems. In urban settings, carbon capture—particularly via nature-based solutions such as vegetation—also enhances air quality, improves thermal comfort, and fosters healthier living conditions. Furthermore, it facilitates ecosystem restoration and biodiversity, while acting as a crucial transitional technique in conjunction with long-term transitions to renewable energy and low-carbon infrastructure.

These vertical structures housing plants are not only decorative barriers. VGS are living green walls that ascend the exteriors of buildings or opulent vertical gardens that flourish within.  In tropical regions, they provide purposes beyond just aesthetics.  They assist in sequestering carbon dioxide (COâ‚‚) (Marchi et al., 2014) as well as regulating temperatures in indoor and outdoor environments (Perini & Magliocco, 2014). Few plants thrive on vertical surfaces; nevertheless, tropical species such as Asplenium nidus, Pothos spp., and Philodendron spp. excel in such environments.  They exhibit fast growth, need minimal maintenance, and are effective in carbon sequestration.

A VGS resembles a garden oriented vertically. Vertical greenery is a system in which plants are cultivated in planter boxes, small pots, or on specially built vertical surfaces on walls (Ghazalli et al., 2018) (Figure 1). The plants were selected to thrive vertically, facilitated by lightweight soil, irrigation systems, and structural reinforcement. They are often located at hotel entrances, in office lobbies, or within shopping malls. VGS are aesthetically pleasing and environmentally beneficial, particularly in tropical regions where abundant light and rainfall facilitate year-round plant growth.

Figure 1: Direct greening (plants affixed directly to walls), indirect greening (utilizing a mesh framework), and modular vertical green systems (employing a waterproof pocket mechanism) (source: Ghazalli et al., 2019)

COâ‚‚ significantly contributes to the warming of the Earth. Plants absorb COâ‚‚ from the atmosphere during photosynthesis, converting it into oxygen and sequestering carbon in their foliage and stems. Even small-sized green infrastructures such as VGS, can have an impact, despite forests performing the majority of ecological functions globally. Wong et al., (2003) indicate that green walls can sequester up to 5 kilograms of COâ‚‚ per square meter annually in nations such as Singapore. Although it may seem insignificant, the cumulative impact becomes substantial when considered across whole buildings and communities.

Previous research has demonstrated that indoor VGS (iVGS) not only decrease particulate matter but also enhance individuals' well-being and comfort (Figure 2). Buildings equipped with VGS exhibited enhanced internal temperature stability, improved humidity control, and an overall more pleasant environment (Ghazalli et al., 2018; Ghazalli & Brack, 2023). Individuals residing or employed in proximity to these systems often report feeling more tranquil and alert. They state the iVGS makes the space more attractive, hence encouraging prolonged occupancy by individuals.

A notable advantage of green walls in tropical regions is their ability to inhibit mildew growth (Tudiwer & Korjenic, 2017). Mold thrives in humid, inadequately ventilated environments, a prevalent issue in our region. VGS have the potential to mitigate the risk of mold proliferation by regulating humidity levels and enhancing air circulation. It is an economical and natural method for moisture removal that requires minimal energy expenditure. Further study might further strengthen this hypothesis.

Figure 2: iVGS used in a study that demonstrated not only decreases particulate matter but also enhance individuals' well-being and comfort, installed at Fenner School of Environment and Society, Australian National University.

VGS, undoubtedly, has its own challenges. Considerations include installation costs, maintenance expenses, and structural capacity to support weight.  However, the environmental and health advantages far surpass the costs—particularly when VGS are incorporated into the building's design from the outset. Governments and builders may facilitate by providing incentives, including VGS into green construction laws, and financing research and training for landscape professionals.

VGS demonstrates that nature need not be excluded from urban environments by transforming vacant walls into flourishing ecosystems.  Conversely, we may reconstruct it in a manner that is aesthetically pleasing, enduring, and sagacious.

Reference:

Ghazalli, A. J., & Brack, C. (2023). Improving Indoor Environmental Quality—Measuring the Potential Contribution of Vertical Greenery Systems. International Journal of Academic Research in Business and Social Sciences, 13(7). https://doi.org/10.6007/IJARBSS/v13-i7/17965

Ghazalli, A. J., Brack, C., Bai, X., & Said, I. (2018). Alterations in use of space, air quality, temperature and humidity by the presence of vertical greenery system in a building corridor. Urban Forestry & Urban Greening, 32, 177–184. https://doi.org/10.1016/j.ufug.2018.04.015

Ghazalli, A. J., Brack, C., Bai, X., & Said, I. (2019). Physical and Non-Physical Benefits of Vertical Greenery Systems: A Review. Journal of Urban Technology, 26(4), 53–78. https://doi.org/10.1080/10630732.2019.1637694

Marchi, M., Pulselli, R. M., Marchettini, N., Pulselli, F. M., & Bastianoni, S. (2014). Carbon dioxide sequestration model of a vertical greenery system. Ecological Modelling, 0. https://doi.org/http://dx.doi.org/10.1016/j.ecolmodel.2014.08.013

Date of Input: 03/10/2025 | Updated: 03/10/2025 | marini