Vertical Greenery Systems as Microbial Air Quality Filters for Community Houses Located Near the Landfill Site

Rapid urban development, along with high population growth in Indonesia, has forced some communities to move away from the city center. At the same time, the city needs space for its waste, which is typically deposited in landfill sites. In both cases, the city outskirts have become favored sites for development. As a result, some communities now find themselves living adjacent to a landfill site and must cope with its air pollution. This study assesses the application of a vertical greenery system (VGS) acting as a microbial air quality filter for community houses located near the landfill site in Kampung Nambo in South Tangerang, Indonesia. Six types of plants were selected for analysis. The study found that Hedera helix was the most effective plant for filtering microbes from the air; the highest recording was reaching 717.3 CFU/m³ (day 10). The study also highlighted the presence of solar radiation, additional shading, and natural ventilation combined with the VGS help to improve air quality. Higher temperatures can reduce the microorganisms, thus impacting the number of bacteria and fungi. Every 1 W/m² increase in solar radiation can reduce bacteria by 1.98 to 2.16 CFU/m³.  Furthermore, the insights of this study should encourage both governmental decision-makers and the broader community to reexamine the importance of vertical greening in settlements adjacent to a landfill.

Air quality; Dense settlement; Landfill; Vertical greenery system

2.1. The impact of landfill sites, microbial air quality, and health

Landfill sites are formal locations to manage garbage responsibly for people and the environment. In practice, that may not always be the case. A landfill site near housing settlements and other sensitive locations, such as a market or a waterway, is considered unsafe and a threat to public health that needs to be adequately managed (Daniel et al., 2021). Moreover, waste decomposition generates methane (CH₄) and hydrogen sulfide (H₂S), which have a bad odor and may attract rats, while ammonia (NH₃) causes respiratory illnesses, physiological abnormalities in the lungs, and elevated blood pressure (Axmalia and Mulasari, 2020). Along with chemicals, biological pollutants such as bacteria and fungi are transported by air circulation in the landfill area (Pepper and Gerba, 2015). As we are keen to emphasize throughout local conditions matter. In this case, local biometeorological factors such as temperature, pressure, relative humidity, wind direction, and the substance of waste and leachate create an impact on pathogenic agents’ ability to survive and multiply (Schlosser, Robert and Debeaupuis, 2016). In addition, in an equatorial or tropical environment, like that of Indonesia, building design places a high priority on managing the amount of heat transfer and ventilation (Othman and Sahidin, 2016).

2.2. Vertical Greenery Systems (VGS)

The VGS is categorized as a green facade (GF) or a living wall (LW) based on its construction type and diversity of plants (Fernández-Cañero, Urrestarazu and Perini, 2018). A GF commonly consists of vines and hanging plants applied to walls or balconies at different heights from the building, while a LW is a complex VGS suitable to support the growth of various plants and may be aesthetically pleasing (Fernández-Cañero, Urrestarazu and Perini, 2018). The installation of VGS with the living wall on the exterior has several patterns, such as a mesh and trellis system with planters (Cekic, Trkulja and Došenovic, 2020).

VGS can act as a natural air conditioner to absorb heat (Zaid et al., 2018). Natural ventilation, air quality controllers, and thermal comfort with green spaces are part of a VGS system on a building's facade in highly populated settlement areas (Megahed and Ghoneim, 2021). To improve visual comfort inside the home, VGS is additionally utilized as a shield from direct solar radiation (Stephenson et al., 2013; Funo, Yamamoto, and Silas, 2002). In short, depending on the scale at which it is implemented VGS can help mitigate local to wider Urban Heat Island (UHI) effects and reduce air quality problems.

Grass and ornamental plants in VGS, such as Cordyline fruticosa, Phyllanthus cochinchinensis, Nephrolepis exaltata, and ornamental plants like Philodendron burle-marxii can reduce heat and air pollution (Ghafar et al., 2020). While other plant species can also be used with VGS to filter airborne particles, like Dracaena deremensis, Neomarica gracilis, Philodendron cordatum, Schlumbergera truncata Hybrids, Monstera deliciosa, Nephrolepis biserrata, Hoya pubicalyx, and Cissus rhombifolia (Ghazalli et al., 2018). In addition, Hedera helix plants with a  20 cm thickness are not only capable of reducing heat but also acting as a wind barrier (Kraus, Žáková and Žák, 2020; Castellanos-Arévalo et al., 2016; Minister of Health Republic of Indonesia, 2011). The density of Passiflora plants is expected to impact the thermal experience (Widyahantari, Alfata, and Nurjannah, 2020).

Biochar is frequently used to boost the viability and efficacy of VGS (Kraus, Žáková and Žák, 2020). Based on a preliminary study from Puteri (2016), 59 plant species were examined to see which had the best pot systems for VGS. Alternanthera ficoidea stood out for having the highest index value for plants' capacity to produce the maximum supply of 18 O₂/m² with a leaf area of 44 cm². As well as Codiaeum variegatum and other plants with an index of 12. In addition, Philodendron sp., with a leaf area of 363 cm² and an index value of 8, performs well. It is, though, important to evaluate plant performance in a variety of local settings to be confident of their effectiveness, including their acceptability to communities and this will often mean that they are plants recognized locally. For our study, it involves examining the purification abilities of plants in close proximity to a landfill site, taking into account the hot and humid climate of Indonesia.

The anaerobic decomposition of microorganisms in landfills produces ammonia gas (NH₃), which encourages the growth of bacteria, especially from organic waste (Yang et al., 2023a). According to the Indonesian health standard, the upper range for germ threshold with harmful fungi and bacteria is 700 CFU/m³ (Minister of Health Republic of Indonesia, 2011). International standards, such as the American Conference of Governmental Industrial Hygienists (ACGIH), are stricter and set a threshold of 500 CFU/m³. This more demanding requirement has become mandatory for some tropical countries, such as Brazil and Singapore (Castellanos-Arévalo et al., 2016). Another challenge for many landfill sites in Indonesia, including our case study, arises from biological activity brought on by sewer decomposition and stagnant water. This results in the formation of hydrogen sulfide gas (H₂S), which has a strong odor (Elwood, 2021; Azima, 2016). Previous research has suggested that vegetation can be used to reduce high levels of bacteria and fungi in settlement areas near landfills (Fithri, 2021; Kumar et al., 2019). However, where land is scarce, as in our case study, there are limited opportunities to create traditional vegetation barriers.

A previous study by Rakhshandehroo mentioned that VGS is primarily applied on the façade with varying degrees of installation complexity to support building performance, such as reducing noise and insulating the building's envelope through solar reflection, heat transfer from the leaves and photosynthesis or evapotranspiration, among other things (Rakhshandehroo, Mohd-Yusof, and Deghati-Najd, 2015). Additionally, VGS has been found to reduce energy usage from 9.5% to 18% in commercial buildings and decrease the harmful effects of UV light on the building's (Rakhshandehroo, Mohd-Yusof, and Deghati-Najd, 2015; Sathien, Techato and Taweekun, 2013).

2.3. VGS and shading: reducing solar radiation

The range of optimal daylight intensity for housing in a tropical climate is about 3–7 W/m² (DKI Jakarta Provincial Government, 2012). Lighting and ventilation are frequently connected. Therefore, external improvements, such as adding shade in the form of trees or air bricks and patterned tiles, can lower temperatures in settlements to between 18°C and 30°C and ameliorate internal comfort (Kusumawardhani, 2011; Minister of Health Republic of Indonesia, 2011). Well-planned shade can increase a city's aesthetic appeal lessen the consequences of heat generation (Macher, 1989) and reduce the risk of illness (Hollands and Korjenic, 2021).

3.1. Case Study: Kampung Nambo, South Tangerang, Indonesia

South Tangerang City is one of the fastest-growing cities in Indonesia and is close to Jakarta. South Tangerang’s landfill is located in Kampung Nambo. The community next to the landfill site is home to 40% of the households in Kampung Nambo (Dewi et al., 2019). The area was chosen as a case study due to its environmental issues.

Figure 2 The vicinity of Kampung Nambo Serpong with the view of a landfill as background

The average temperature is measured daily for the whole year during the study to be between 27.46°C and 28.04°C. Climate change is likely to lead to further increases in average temperature, making efforts to improve cooling within the community even more important. Like other tropical areas, local weather has a rainy season. This means that there is a high average annual humidity of around 80%. The average wind speed is between 1.44 and 1.57 m/s (BMKG, 2022) so might potentially blow air pollution into the neighborhood, which is only 500 meters away from the landfill.

3.2. Data Collection

Data sets were collected during the ‘shifting season’ in Indonesia - the time between dry and rainy seasons – for six weeks between March and April 2022. This study captured data from wet to dry seasons and our measurements took place during high rain precipitation, drought, and strong wind speed. The sampling was done outdoors, using one control box, and six VGS box models. Within the timeframe of the study, microbial air quality tests in the laboratory were done twice a week.

3.3. The Box Model

Figure 3 Experiment Box Model Placement in Kampung Nambo Serpong, RT 03 RW 04, South Tangerang City

3.3.1. Plant Selection

Figure 4 Experimental box model with six selected plants and one control box experimented over a period from day 1 to day 12

3.3.2. The Box Model Material and the Measuring Tools

The box model consists of opaque walls, a corrugated roof in white color, and a louvre window as an opening. Our on-site observations of the community noted that dwelling windows had restricted openings, and the average of dwelling size is 21 m² - 36 m²  (Minister of Settlement and Regional Infrastructure Republic of Indonesia, 2002). Although we would have liked to replicate a typical dwelling in our study, due to restrictions on the available space for the study, the box model is smaller than the average dwelling size in the community (see Figure 5). Where necessary, we have been cautious in our interpretation of the data to take account of the size differences.

Figure 5 The placement of measuring tools, including a data logger, an anemometer, a solar meter, a FLIR camera, and an Impactor EMS E6-400, for tested the experimental box from day 1 through day 12

3.4. The Microbial Air Quality Test

This study also collected sampling data on bacteria and fungus to see if it fell within the Indonesian Health Standard of 700 CFU/m³, for the total number of germs (Minister of Health Republic of Indonesia, 2011). The microbial air quality tests were conducted in the laboratory at the Universitas Indonesia. Due to the restricted availability of media manufacturing and the laboratory's capacity to examine germ sample growth, data collection was limited to two days a week. However, this regularity provides for consistent and accurate findings.  Also, during our study period, air pollution from the landfill site tends to stay within its bounds.

The microbial air quality test system used the NIOSH 0800 and 0801 techniques and ACGIH recommendations (Odonkor and Mahami, 2020; Er et al., 2015). To assess the amount of particle deposition in the container and the number of microbial colonies of air pollutants per unit of air volume, the culture of bacteria and fungi must also be tested 48 hours after the sampling.

4.1. Outdoor air quality and VGS

Figure 6 Average Outdoor Air Quality in Serpong-Banten, Indonesia, was evaluated from week 1 through week 6 during the experimental period

This index, as shown in Figure 6, indicates high air pollution for weeks 4-6, especially for PM 2.5, which is up to 6.5 times higher than the WHO standard (WHO, 2021). As a result, asthma, lung, heart, and other medical conditions may develop (Izzatuljannah and Zakiah, 2021). The presence of a settlement near the Cipeucang Landfill, the growth of industries, factories, and businesses with high pollution intensity, as well as the reduction in green open space have all contributed to a considerable rise in pollution over time (Izzatuljannah and Zakiah, 2021).

Bacterial colonies were measured by an Impacter EMS-E6 400 holes device and validated with a correction table (see Appendix 1 for further details). The total range of bacterial colonies outdoors = (485.86 – 556.53) CFU/m³ (these numbers mean that there were 485.86 – 556.53 bacterial colonies in 1m³) and the bacterial colonies were in the acceptable range for Indonesia at <700 CFU/m³  (Minister of Health Republic of Indonesia, 2011) but higher than more stringent regulations to be found in other tropical countries such as Brazil and Singapore.

The six VGS plants were able to effectively filter microbiological air. Therefore, they have the potential to achieve similar results in settlement areas near the landfill. As shown in Table 1, the plants are capable of filtering microbial air with a range of 1,162.59 to 1,790.96 CFU/m³. These are significant differences that highlight the importance of understanding local geographic conditions when establishing VGS. As expected, the Hedera helix can provide a higher-level filter for microbial air than other plants at a range from 1,636.38 to 1,790.96 CFU/m³. It is followed by Alternanthera ficoidea with a range from 1,545.16 to 1,703.11 CFU/m³, and Nephrolepis cordifolia with a range from 1,522.92 to 1,677.91 CFU/m³.  However, it was found during plant testing that the control box with a louvre window was also efficient and could filter the air with a range from 1,472.37 to 1,593.07 CFU/m³. These conditions occurred due to the inlet and outlet in the louvre window, as it encouraged airflow to indoor space, harnessed natural ventilation patterns to filter the incoming air, captured larger particles, and created a continuous flow of fresh outdoor air.

Table 1 Ranking of the best plants for reducing microbial populations

The remaining three plants that can perform as an air filter are Vernonia elliptica, Sansevieria trifasciata, and Philodendron sp. Vernonia elliptica has a range of 1,182.73 to 1,271.56 CFU/m³, Sansevieria trifasciata ranges from 1,169.75 to 1,253.27 CFU/m³, and Philodendron sp. ranges from 1,162.59 to 1,243.77 CFU/m³. As a result, the VGS with a mesh and trellis system type on an orientation facing the landfill area had the potential to improve the air quality, and from previous studies, we know it can also help reduce heat (Shuhaimi et al., 2022; Perini et al., 2011). Plants ability to develop, as seen in Table 1, demonstrates that their high leaf density makes them more effective at filtering microbes such as bacteria and fungi in the air.

4.2. Germs and air quality

Figures 7 and 8 show the lower and upper ranges of the germ numbers, an indicator of air quality, which fluctuates for 12 days for which measurements took place over the six-week study. The reason for the shortened time frame for the measurement of the germs is because of the two-day time period that was required to prepare the culture before it could be used to test the samples from the box models.  Days 1,3-4, 6, 9-10, and 11 showed that the germ intensity was above the safe limits, which range from 700 to 2,300 CFU/m³. Days 4 and 9 had the highest levels at 2,300 CFU/m³. In contrast, during days 2, 5, 7-8, and 12 the intensity of germs fell below the limit of 700 CFU/m³. During day 4, Box Model 2 showed the highest level of bacteria at 2,000–2,300 CFU/m³. Box model 6 had the lowest concentration at 100–200 CFU/m³ on day 11. Additionally, the outside area on day 9 had a germ index of around 1,700 to 1,800 CFU/m³, while day 7 had a germ index of under 100 CFU/m³. Weather affects how many and how few germs are present; for example, sunny weather tends to have fewer germs than overcast or wet weather. Considering various weather conditions is critical for understanding the variability in the results and highlights the value of detailed local studies. The figures below indicate that germ levels in the box model varied over a short period of time. It can be observed that sunny weather generally resulted in fewer germs (Figure 7) compared to overcast or wet conditions. Despite this, both figures demonstrate similar patterns throughout the study period. The variation between the lower limit (Figure 7) and upper limit (Figure 8) for germ levels remains consistent, highlighting the significance of local climatic conditions.

Figures 7 and 8 also display the changes in the control box model and Box model 2 that housed Philodendron sp. plants. Data for box model 2 shows it is the weakest performer (i.e. the lowest ranked of the six plants) but does illustrate the minimum gain that can be made by green infrastructure. Looking at the figures in more detail shows that over the three weeks for data collection the trend on day 4, for Box model 2 showed an increase in the number of germs, as it rose from 2,004.4 to 2,308.29 CFU/m³. Meanwhile, data from the control box model shows that on the same day, a lower figure was recorded for the number of germs of 555.65 and ranged up to 640.45 CFU/m³. This is an unexpected finding because other studies show that plants will filter germs (Kumar et al., 2019). It is essential to understand why such an anomaly may arise as it illustrates the challenges of undertaking community-level work in which the environment can only be partially controlled. During the observation periods when the researchers were on site, we noticed that chickens began moving in and out of Box Model 2 before recording data on day 4. However, this situation cannot happen in the Control Box model due to the louvre window which blocks chickens from entering the box. We assumed the chickens would have brought germs into the box, which explains the surprisingly high level of germs recorded. However, this assumption needs to be further investigated (see Appendix 2).

Figure 7 The lower range of germ quantities graph in an outdoor, control box model, and box models 1-6 for 6 weeks

Figure 8 The upper range of germ quantities graph in an outdoor, control box model, and box models 1-6 for 6 weeks

As shown in Figure 9, Box Model 6 (Hedera helix) has lower germ trends than the other box models. The highest recording was on day 10, reaching 717.3 CFU/m³. Additionally, changes in germ density between days 7–12 revealed a range from 100 to 700 CFU/m³, which was lower than the other box models. The humidity in box 6 model was between 60–100%, while the temperature ranged between 30–38°C. The survival of airborne microorganisms is significantly influenced by temperature and humidity levels (Pepper and Gerba, 2015). Nevertheless, the type of microorganisms, the duration of exposure, and the surrounding environment all have varying impacts (Pepper and Gerba, 2015). BKMG data for 2022 shows that in Serpong-Banten, Indonesia the average temperature was 37°C and the relative humidity almost 80% (BMKG, 2022), and these conditions constrain the spread of germs.
Figure 9 The comparison graph between the lower and upper range of germ quantity with temperature (a & b) and humidity (c & d) in an outdoor, control box model, and box model 6 filter better than other box models

4.3. Solar radiation and air quality

Solar radiation substantially impacts the growth of germ intensity in the field (Pepper and Gerba, 2015). This study analyzed the amount of sun radiation over 12 days in 6 weeks. The 12-day recording of sun radiation is because measures were taken on visits to the site. Figure 10 shows the impact of incoming radiation levels on the box models for 12 days and the changing solar radiation outdoors. The outdoor solar radiation intensity ranges from 628.75 to 925.25 W/m² on days 1, 6, 8, and 10. A comparison of these two graphs (Figure 10 a & b) also demonstrates that each box type has successfully lowered the amount of incoming radiation by 900 W/m²; however, compared to box models 4-6 and the control box model, box models 1-3 have lower barrier effectiveness. As an outcome, the control box model and boxes 5 and 6 are more effective than boxes 1 to 4 in the reduction of solar radiation intensity.

Weather variables influenced solar radiation levels significantly during the observation days. For instance, days 1, 6, 8, and 10 show high intensity of solar radiation up to 925.25 W/m² because of hot weather with high temperatures. In contrast, day 9, rainy day conditions, and low temperatures show low solar radiation of about 600 W/m². Moreover, hot weather conditions could reduce germs but substantially increase temperature, and cloudy or rainy weather increases germs but initiates low temperatures. Therefore, adding a vertical greenery system could improve the effectivity of shading for temperature but not lower the germ count.

Figure 10 Solar radiation graphs a) control box model, box models 1-6 for 3 weeks and b) outdoor for consecutive 6-week

The data shows that the density of the bacteria and fungi in the air is also impacted by factors related to climate conditions (Pepper and Gerba, 2015). The tropical environment in Kampung Nambo Serpong results in high temperatures and a lot of solar radiation. Higher temperatures can reduce the microorganisms; every 1 W/m² increase in solar radiation can reduce bacteria by 1.98 to 2.16 CFU/m³, considerably impacting the number of bacteria and fungi. 

The study evaluated the effectiveness of various plant species in vertical greenery systems (VGS) to enhance air quality in areas near landfills, where green infrastructure is limited. The findings demonstrate that VGS can significantly reduce air pollution, with Hedera helix emerging as the most effective plant for filtering microbes from the air. External factors, such as solar radiation, positively influence VGS performance by promoting plant growth and air filtration, thus further improving air quality. The study underscores the importance of considering local geography, climate, and community needs when implementing green infrastructure. Additionally, it emphasizes the value of a bottom-up approach that involves community participation and accounts for local lifestyles to effectively interpret data and manage unforeseen challenges. These findings are particularly relevant for tropical regions like Indonesia and suggest the need for further research involving a broader range of plants and extended data collection.

This research was funded by the Directorate of Research and Development, Universitas Indonesia under Hibah PUTI 2022 (Grant No. NKB-332/UN2.RST/HKP.05.00/2022).  The authors would also like to express their appreciation and gratitude to the residents of Kampung Nambo Serpong and everyone who actively participated in this study.

Abdul-Rahman, Wang, C., Rahim, A.M., Loo, S.C., Miswan, N., 2014.Vertical Greenery Systems (VGS) in Urban Tropics. Open House International, Volume 39(4), pp. 42–52

Ahad, M.A.A., Sullivan, F., Demšar, U., Melhem, M., Kulu, H., 2020. The Effect of Air-Pollution and Weather Exposure on Mortality and Hospital Admission and Implications for Further Research: A Systematic Scoping Review. PLoS ONE, Volume 15(10), p. e0241415

Axmalia, A., Mulasari, S.A., 2020. Dampak Tempat Pembuangan Akhir Sampah (TPA) Terhadap Gangguan Kesehatan Masyarakat (The Impact of Final Waste Disposal Sites (TPA) on Public Health Problems). Jurnal Kesehatan Komunitas, Volume 6(2), pp. 171–176

Azima, S.S., 2016. Analisis Risiko Hidrogen Sulfida Pada Kesehatan Anak-Anak Yang Bermukim Di Pemukiman Tempat Pengelolaan Sampah Akhir (TPA) Cipeucang Tangerang Selatan Tahun 2016 (Risk Analysis of Hydrogen Sulfide in Children's Health In Residential Waste Management Site (TPA) Cipeucang South Tangerang).  Thesis, Graduate Program, Universitas Indonesia, Indonesia

Badan Meteorologi, Klimatologi, dan Geofisika (BMKG), 2022 Data Iklim Harian Tahun 2022 (Daily Climate Data 2022). Tangerang Selatan. Available at: https://dataonline.bmkg.go.id/data_iklim, Accessed on May 16, 2022

Bustami, R.A., Belusko, M., Ward, J., Beecham, S., 2018. Vertical Greenery Systems: A Systematic Review of Research Trends. Building and Environment, Volume 146, pp. 226–237

Castellanos-Arévalo, A.P., Camarena-Pozos, D.A., Castellanos-Arévalo, D.C., Rangel-Córdova, A.A., Peña-Cabriales, J.J., Arevalo-Rivas, B., Pena, D.G.d., Maldonado-Vega, M., 2016. Microbial Contamination in the Indoor Environment of Tanneries in Leon, Mexico. Indoor and Built Environment, Volume 25(3), pp. 524–540

Cekic, S., Trkulja, T., Došenovic, L., 2020. Typology of Vertical Greenery System. Gradevinar, Volume 72(11), pp. 1011–1019

Charoenkit, S., Yiemwattana, S., 2016. Living Walls and Their Contribution to Improved Thermal Comfort and Carbon Emission Reduction: A Review. Building and Environment, Volume 105, pp. 82–94

Coma, J., Pérez, G., de Gracia, A., Burés, S., Urrestarazu, M., Cabeza, L.F., 2017. Vertical Greenery Systems for Energy Savings in Buildings: A Comparative Study Between Green Walls and Green Facades. Building and Environment, Volume 111, pp. 228–237

Corson-Knowles, T., 2012. The Vertical Gardening Guidebook: How to Create Beautiful Vertical Gardens, Container Gardens and Aeroponic Vertical Tower Gardens at Home. 2^nd editon. Vertical Gardening Group

Daniel, A.N., Ekeleme, I.K., Onuigbo, C.M., Ikpeazu, V.O., Obiekezie, S.O., 2021. Review on Effect of Dumpsite Leachate to The Environmental and Public Health Implication. GSC Advanced Research and Reviews, 7(2), pp. 051–060

Dewi, O.C., Ellisa, E., Chairunnisa, I., Asyera, E., 2019. Reducing Environmental Degradation in Kampung Nambo by Cutting the Critical Contamination Points. IOP Conference Series: Earth and Environmental Science, Volume 366(1), p. 012002

Direktorat Jenderal Cipta Karya, 2020. Pedoman Desain Pasif Rumah Susun untuk Iklim Tropis Panas Lembap di Indonesia: Iklim dan Kenyamanan Termal di Indonesia. Satwiko, P., Nugroho, A.M., (ed.), Jakarta: Balai Sains Bangunan Direktorat Bina Teknik Permukiman dan Perumahan Kementerian Pekerjaan Umum dan Perumahan Rakyat, pp. 28–34

DKI Jakarta Provincial Government, 2012. Sistem Pencahayaan, Panduan Pengguna Bangunan Gedung Hijau Jakarta (Lighting System, Green Building User Guide Jakarta). DKI Jakarta Provincial Government, Jakarta

Elwood, M., 2021. The Scientific Basis for Occupational Exposure Limits for Hydrogen Sulphide—A Critical Commentary. International Journal of Environmental Research and Public Health, Volume 18(6), pp. 1–17

Er, C.M., Sunar, N.M., Leman, A.M., Othman, N., Emparan, Q., Parjo, U.K., Gani, P., Jamal, N.A., Ideris, N.A., 2015. The Evaluation of Indoor Microbial Air Quality in Two New Commissioning Higher Educational Buildings in Johor, Malaysia. Applied Mechanics and Materials, Volume 773–774, pp. 1068–1072

Fang, X., Li, J., Ma, Q., 2023. Integrating Green Infrastructure, Ecosystem Services and Nature-Based Solutions for Urban Sustainability: A Comprehensive Literature Review. Sustainable Cities and Society, Volume 98, p. 104843

Fernández-Cañero, R., Urrestarazu, L.P., Perini, K., 2018. Vertical Greening Systems: Classifications, Plant Species, Substrates. Nature Based Strategies for Urban and Building Sustainability, Volume 2018, pp. 45–54

Fithri, N.K., 2021. Analisis Kepadatan Hunian terhadap Angka Bakteri Udara dalam Rumah Di Sekitar TPA Sampah (Analysis of Residential Density on Air Bacteria Figures in Houses Around Landfills). Dunia Keperawatan: Jurnal Keperawatan dan Kesehatan, Volume 9(2), p. 268

Funo, S., Yamamoto, N., Silas, J., 2002. Typology of Kampung Houses and Their Transformation Process--A Study on Urban Tissues of an Indonesian City. Journal of Asian Architecture and Building Engineering, Volume 1(2), pp. 193–200

Ghafar, A.A., Said, I., Fauzi, A.M., Shai-in, M.S., Jaafar, B., 2020. Comparison of Leaf Area Index from Four Plant Species on Vertical Greenery System in Pasir Gudang, Malaysia. Pertanika Journal of Science and Technology, Volume 28(2), pp. 735–748

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 and Urban Greening, Volume 32, pp. 177–184

Hollands, J., Korjenic, A., 2021. Indirect Economic Effects of Vertical Indoor Green in The Context of Reduced Sick Leave in Offices. Sustainability (Switzerland), Volume 13(4), pp. 1–19

Hong, W., Ibrahim, K., Loo, S., 2019. Urging Green Retrofits of Building Façades in the Tropics: A Review and Research Agenda. International Journal of Technology, Volume 10(6), pp. 1140–1149

Izzatuljannah, H.F., Zakiah, A., 2021. Isu Polusi Udara Di Kota Tangerang Selatan. In: Seminar Karya & Pameran Arsitektur Indonesia 2021 (Indonesian Architecture Works Seminar & Exhibition 2021), pp. 64–76

Köhler, M., 2008. Green Facades-A View Back and Some Visions. Urban Ecosystems, Volume 11(4), pp. 423–436

Kraus, M., Žáková, K., Žák, J., 2020. Biochar for Vertical Greenery Systems. Energies, Volume 13(23), p. 6320

Kumar, P., Druckman, A., Gallagher, J., Gatersleben, B., Allison, S., Eisenman, T.S., Hoang, U., Hama, S., Tiwari, A., Sharma, A., Abijith, K.V., Adlakha, D., McNabola, A., Astell-Burt, T., Feng, X., Skeldon, A.C., Lusignan, S.d., Morawska, L., 2019. The Nexus Between Air Pollution, Green Infrastructure and Human Health. Environment International, Volume 133(October), p. 105181

Kusumawardhani, C., 2011. Karakteristik Fisik Permukiman Kumuh di Perkotaan Berdasarkan Tipologi Penataan Studi Kasus: Menteng Atas dan Kampung Melayu (Physical Characteristics of Urban Slums Based on Typology of Arrangement Case Study: Menteng Atas and Kampung Melayu). Universitas Indonesia, Depok, Indonesia

Macher, J.M., 1989. Positive-Hole Correction of Multiple-Jet Impactors for Collecting Viable Microorganisms. American Industrial Hygiene Association Journal, Volume 50(11), pp. 561–568

Megahed, N.A., Ghoneim, E.M., 2021. Indoor Air Quality: Rethinking Rules of Building Design Strategies in Post-Pandemic Architecture. Environmental Research, Volume 193, p. 110471

Minister of Health Republic of Indonesia, 2011. Peraturan Menteri Kesehatan Republik Indonesia No. 1077/Menkes/PER/2011 (Regulation of the Minister of Health of the Republic of Indonesia No. 1077/Menkes/PER/2011).  Minister of Health Republic of Indonesia, Indonesia

Minister of Public Works Republic of Indonesia, 2013. Peraturan Menteri Pekerjaan Umum Republik Indonesia Nomor 03/PRT/M/2013 Tentang Penyelenggaraan Prasarana Dan Sarana Persampahan Dalam Penanganan Sampah Rumah Tangga Dan Sampah Sejenis Sampah Rumah Tangga Dengan (Regulation of the Minister of Public Works of the Republic of Indonesia Number 03/PRT/M/2013 Concerning the Provision of Waste Infrastructure and Facilities in Handling Household Waste and Waste Similar to Household Waste With). Minister of Public Works Republic of Indonesia, Indonesia

Minister of Settlement and Regional Infrastructure Republic of Indonesia, 2002. Keputusan Menteri Permukiman dan Prasarana Wilayah Nomor: 403/KPTS/M/2002 Tentang Pedoman Teknis Pembangunan Rumah Sederhana Sehat (Rs Sehat) (Decree of the Minister of Settlement and Regional Infrastructure Number: 403/KPTS/M/2002 Concerning Technical Guidelines for the Construction of Simple Healthy Houses (Healthy Hospitals)). Minister of Settlement and Regional Infrastructure Republic of Indonesia, Indonesia

Odonkor, S.T., Mahami, T., 2020. Microbial Air Quality in Neighborhoods near Landfill Sites: Implications for Public Health. Journal of Environmental and Public Health, Volume 2020, p. 4609164

Oluwafeyikemi, A., Julie, G., 2015. Evaluating the Impact of Vertical Greening Systems on Thermal Comfort in Low Income residences in Lagos, Nigeria. Procedia Engineering, Volume 118, pp. 420–433

Othman, A.R., Sahidin, N., 2016. Vertical Greening Façade as Passive Approach in Sustainable Design’, Procedia - Social and Behavioral Sciences, Volume 222, pp. 845–854

Pan, L., Chu, L.M., 2016. Energy Saving Potential and Life Cycle Environmental Impacts of A Vertical Greenery System in Hong Kong: A Case Study. Building and Environment, Volume 96, pp. 293–300

Pepper, I.L., Gerba, C.P., 2015. Aeromicrobiology. In: Environmental Microbiology. 3^rd edition. United States of America: Elsevier Inc., p. 89.

Perini, K., Ottelé, M., Fraaij, A.L.A., Haas, E.M., Raiteri, R., 2011. Vertical Greening Systems and The Effect on Air Flow and Temperature on The Building Envelope. Building and Environment, Volume 46(11), pp. 2287–2294

Puteri, K.I.S., 2016. Substitusi Bidang Tanam Bagi Tanaman Sebagai Penghasil Oksigen Pada Bangunan Tinggi (Substitution of Planting Areas for Plants as Oxygen Producers in Tall Buildings). Thesis, Graduate Program, Universitas Indonesia, Indonesia

Rakhshandehroo, M., Mohd-Yusof, M.J., Deghati-Najd, M., 2015. Green Façade (Vertical Greening): Benefits and Threats. Applied Mechanics and Materials, Volume 747, pp. 12–15

Renaldi, A., 2020. Indonesia’s Steady Stream of Medical Waste, New Naratif. Available online at: https://pulitzercenter.org/stories/indonesias-steady-stream-medical-waste#:~:text =Cipeucang%20is%20a%202.5-hectare,accommodate%20waste%20from%20around%20 Tangerang, Accessed on November 30, 2022

Rupasinghe, H.T., Halwatura, R.U., 2020. Benefits of Implementing Vertical Greening in Tropical Climates. Urban Forestry and Urban Greening, Volume 53, p. 126708

Ryan, B., Bristow, D.N., 2023. Climate Change and Hygrothermal Performance of Building Envelopes: A Review on Risk Assessment. International Journal of Technology, Volume 14(7), pp. 1461–1475

Sathien, K., Techato, K., Taweekun, J., 2013. Using Vertical Green as Material for Complying Building Energy Code. Advanced Materials Research, Volume 622–623, pp. 1035–1038

Schlosser, O., Robert, S., Debeaupuis, C., 2016. Aspergillus Fumigatus and Mesophilic Moulds in Air in The Surrounding Environment Downwind of Non-Hazardous Waste Landfill Sites. International Journal of Hygiene and Environmental Health, Volume 219(3), pp. 239–251

Shaharuddin, S., Khalil, N., Abdullah-Saleh, A., 2019. Review of Significant Maintenance Criteria for Tropical Green Roofs in Malaysia. International Journal of Technology, Volume 10(1), pp. 69–80

Shuhaimi, N.D.A.M., Zaid, S.M., Esfandiari, M., Lou, E., Mahyuddin, N., 2022. The Impact of Vertical Greenery System on Building Thermal Performance in Tropical Climates. Journal of Building Engineering, Volume 45, p. 103429

Stephenson, J., Crane, S.F., Levy, C., Maslin, M., 2013. Population, Development, and Climate Change: Links and Eff Ects on Human Health. The Lancet, Volume 382(9905), pp. 1665–1673

The World Bank, 2022. Population, total - Indonesia. Available online at: https://data.worldbank.org/indicator/SP.POP.TOTL?locations=ID, Accessed on February 23, 2022

United States Environmental Protection Agency, 2014. Air Quality Index: A Guide to Air Quality and Your Health. Available online at: https://www.airnow.gov/aqi/aqi-basics/, Accessed on March 7, 2022

Universitas Indonesia, n.d. Pemeriksaan Kualitas Udara Mikrobiologi (Microbiological Air Quality Inspection). In: Panduan Praktikum Mikrobiologi Lingkungan (Environmental Microbiology Lab Guide). Jakarta: Universitas Indonesia

Weather, 2022. Today's Air Quality, Banten Indonesia, Weather.com. Available online at: https://weather.com/forecast/air-quality/l/50fb11d0b840deb5f598400621fb6e3cf2f537fbd711b1f 129bc37ae0e01f3e7. Accessed on April 27, 2022

Widyahantari, R., Alfata, M.N.F., Nurjannah, A., 2020. Passiflora as Vertical Greenery Systems in The Building: The Effects on The Indoor Thermal Environments. AIP Conference Proceedings, Volume 2255 p. 070011 

World Health Organization (WHO), 2021. Ambient (Outdoor) Air Pollution, World Health Organization. Available Online at: https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health, Accessed on October 5, 2021

Yang, F., Yousefpour, R., Zhang, Y., Wang, H., 2023a. The Assessment of Cooling Capacity of Blue-Green Spaces in Rapidly Developing Cities: A Case Study of Tianjin’s Central Urban Area. Sustainable Cities and Society, Volume 99, p. 104918

Yang, S., Kong, F., Yin, H., Zhang, N., Tan, T., Middel, A., Liu, H., 2023b. Carbon Dioxide Reduction from an Intensive Green Roof Through Carbon Flux Observations and Energy Consumption Simulations. Sustainable Cities and Society, Volume 99, p. 104913

Zaid, S.M., Perisamy, E., Hussein, H., Myeda, N.E., Zainon, N., 2018. Vertical Greenery System in Urban Tropical Climate and Its Carbon Sequestration Potential: A Review. Ecological Indicators, Volume 91, pp. 57–70