DOI: 10.3303/CET2291096 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Paper Received: 24 February 2022; Revised: 1 April 2022; Accepted: 25 May 2022 
Please cite this article as: Di Talia V., Antonioni G., 2022, A Methodology for the Evaluation of the Voc Abatement Capacity of Different 
Species of Potted Ornamental Plants in Phytoremediating Indoor Air, Chemical Engineering Transactions, 91, 571-576  
DOI:10.3303/CET2291096 
  

 CHEMICAL ENGINEERING TRANSACTIONS  
 

VOL. 91, 2022 

A publication of 

 

The Italian Association 
of Chemical Engineering 
Online at www.cetjournal.it 

Guest Editors: Valerio Cozzani, Bruno Fabiano, Genserik Reniers 
Copyright © 2022, AIDIC Servizi S.r.l. 

ISBN 978-88-95608-89-1 ISSN 2283-9216 

A Methodology for the evaluation of the VOC Abatement 

Capacity of Different Species of Potted Ornamental Plants in 

Phytoremediating Indoor Air  

Valentina Di Talia, Giacomo Antonioni* 

University of Bologna, CIRI Fonti Rinnovabili, Ambiente, Mare ed Energia, Via Sant’Alberto 163, 48123, Ravenna  

giacomo.antonioni3@unibo.it  

Since the end of the ’80s, it has been known that potted ornamental plants can remediate Volatile Organic 

Compounds (VOCs) from indoor air and, to date, a significant number of species have been tested in controlled 

environments to quantify their abatement capacity concerning specific VOCs. However, the experimental 

methodologies are not standardised yet, and different units and approaches are used to quantify the removal 

capacity of the species. Consequently, in most cases, the results obtained are not comparable and, most 

importantly, directly exploitable to set up phytoremediation interventions in real settings.  

This study proposes a new method for evaluating and comparing the VOC removal capacity of different plant 

species and a review, produced according to this methodology, of the results obtained in previous studies. 

Considering that the VOC abatement is related to the entire plant system and that the uptake cannot be 

considered neither a zero nor a first-order removal process but a hybrid of the two, the proposal consists in 

modelling the removal analogously to biological processes. In the first instance, this approach allows a simple 

but effective assessment of the results obtained in different tests, making possible an objective choice of the 

best performing species for phytoremediation applications in real settings. While applying this methodology to 

existing experimental studies, it was considered essential to rigorously review their protocols as the removal 

depends on many factors, inter alia the chamber dimensions, the environmental conditions, the initial pollutant 

concentrations and the metabolic characteristics of the tested species. This application has aimed to set the 

basis for an accurate and more complete comparison of the results obtained in controlled environment 

experimentations and, also, to prepare the way to a standardization of the methodologies.  

Plant-based remediation interventions could be a simple, green and innovative solution to address the complex 

indoor air pollution problem. The approach proposed in this paper is an essential step towards a rational design 

of these interventions, allowing, in particular, the assessment of the actual remediation capacity of different plant 

species tested in various conditions. 

1. Introduction 

Indoor air pollution is recognised globally as a public health hazard with substantial social and economic 

repercussions (Soreanu et al., 2013). Volatile Organic Compounds (VOCs) are an important class of indoor air 

pollutants as they are ubiquitous and are known to determine a wide variety of adverse health effects, even at 

low concentrations (Bernstein et al., 2008). Despite this, to date, the techniques available for removing VOCs 

from indoor air are often ineffective, especially for gaseous contaminants (Suárez-Cáceres et al., 2021). 

The idea of using potted ornamental plants to phytoremediate indoor air from VOCs was introduced at the end 

of the ‘80s (Wolverton and McDonalds,1982; Wolverton et al., 1984; Wolverton et al., 1989). These pioneering 

studies quantified the VOC removal capacity of a group of plant species for the first time, providing the basis for 

the following empirical research on this subject. In recent years, the interest in plant-based solutions for air 

depuration has been growing and, to date, the abatement capacity of a significant number of plant species has 

been tested in controlled environments (Han and Ruan, 2020).  

 

571



The abatement capacity of a plant species concerning a specific VOC, generalising from the literature (Kim et 

al., 2018), can be assessed with tests in closed environments where a known pollutant concentration is injected 

in a sealed chamber to quantify the abatement of a specimen over a defined time period. As the experimental 

methodologies are not standardised yet, and different approaches and units to describe the removal are used, 

the results obtained are often not comparable and directly usable.  

The principal factors that can influence the plant VOC abatement need to be evaluated to read the results 

rigorously.  

The initial and final pollutant concentration in the chamber, the tested specimen leaf area, and the controlled 

chamber volume are the minimal data required to model the depletion capacity of a species for a selected 

contaminant (Di Talia and Antonioni, 2021) appropriately. The leaf area is often the most used parameter to 

quantify the dimensions of the plants and, consequently, the uptake. It is in fact well known that the principal 

VOC removal pathway concerns the plant leaves (i.e. stomata and cuticle), but it has also been proven that the 

microorganisms residing in the roots and in the growing medium play an essential role in the abatement. To 

date, it is still difficult to assess the actual incidence of these pathways for each species and at different 

environmental conditions rigorously, mainly because of the complexity of the overall plant removal process in 

which the contaminants are “captured” by the different parts of the plant and then translocated and metabolised 

(Dela Cruz et al.2014).The review of Dela Cruz et al.(2014) just cited provides an interesting overview of the 

additional factors that should be considered while evaluating the plant VOC abatement. Among them, the most 

important are the plant metabolic and morphological features and environmental conditions (temperature, 

relative humidity, and presence of light). Species peculiarities can strongly affect the removal, and they should 

be regarded to read the results of the tests correctly. To give an example, plants with Crassulacean Acid 

Metabolism (CAM) perform the uptake through the stomata also in conditions of darkness (Gong et al., 2019), 

which is evidently a considerable advantage while applying this mitigation strategy in real environments. 

This work proposes a methodology for comparing, straightforwardly, the abatement capacities of different plant 

species obtained with different experimental protocols. The purpose is to support the designer in selecting the 

best species to remediate a specific contaminant, knowing its initial concentration in the indoor environment to 

address. Starting from the selection of plant species with superior VOC purifying ability presented by Kim et al. 

(2018), the methodology was applied to produce an immediately usable database, , of the results achieved in 

previous tests. To conclude, an example of how this database can be employed will be illustrated. The 

contaminant chosen for this last application is formaldehyde, one of the most investigated and common indoor 

air contaminants. 

2. Methodology 

Potted plants are proven to remediate indoor air from VOCs; nevertheless, currently, there is no standardised 

method to assess their abatement capacity in controlled environments univocally. The number of studies 

regarding the topic is increasing, and the necessity to define a methodology to compare the results already 

obtained ad to give a direction for further studies is evident.  

A straightforward approach is proposed for this intent. The idea is to consider a plant as a system and model 

the VOC abatement analogously to biological removal processes.  

It is well known that the VOC removal occurs predominantly through the plant aerial part (i.e. the plant leaves), 

but the action of microorganisms residing in the root zone should also be regarded. Due to the differences in 

the pathways involved in the removal, the overall plant VOC abatement kinetics cannot be seen exclusively as 

a pseudo first-order or a zero-order removal process. The idea of modelling it as a hybrid of the two, as for 

biological processes, seems the most reasonable approach to follow. The fact that it is still challenging to 

determine the relative importance of the VOC uptake pathways in the overall phytoremediation process also 

has to be acknowledged. 

In order to quantify the abatements obtained in experimentations univocally, the volume of the controlled 

chamber, the total plant area of the specimen tested and the initial and final pollutant concentrations in the 

chamber after a defined time period are the essential parameters to consider, since they can be used, according 

to this methodology, to calculate the species and pollutant specific removal rates per unit leaf area η0 and η1 as 

shown in Eq(1). 

𝜂𝑖 =  𝑘𝑖  
𝑉

𝐴
 (1) 

being V the volume of indoor air in the control chamber (m3), A the entire plant area (m2) and ki the removal rate 

of zero or first order (i=0,1).  To better characterise the specimens and consider this study's aims, the total plant 

area A (m2) is calculated as the sum of the leaf area and the root zone area, the latter approximated for simplicity 

to the area of the pot’s base (this last term was enclosed to partially regard the contribution of the microorganism 

572



residing in soil and roots). Concerning the removal rates of zero or first-order k0 (μg/m3h) and k1 (1/h), they can 

be easily determined considering only the depletion term of a simple indoor air model as the GIOAP 

(Moschandreas and Stark, 1978), as shown in Eq(2) and Eq(3)  

𝑘1 = −  
ln (

𝑐𝑓
𝑐0

)

𝑡
 

(2) 

𝑘0 =  
(𝑐0 −  𝑐𝑓 )

𝑡
 (3) 

In these equations, c0 and cf are the initial and final concentrations in the control chamber (μg/m3), and t is the 

experimental time (h). Evidently, the zero and first-order removal rates per unit leaf area η0 and η1 defined by 

Eq(1) are then expressed in μg/m3h and m/h, respectively. 

 

In analogy with the biological removal processes and considering the elements just presented, the overall VOC 

abatement velocity, expressed in μg/m3h, can be written as function of indoor pollutant concentration c as shown 

in Eq(4). 

𝑟 =
𝑘0 𝑐

𝑘0
𝑘1

+ 𝑐
=  

𝜂0  
𝐴
𝑉

𝑐

𝜂0
𝜂1

+ 𝑐
 (4) 

With this approach, it is possible to evaluate the performance of a plant species in abating a specific contaminant 

concentration in the indoor environment. Moreover, plotting this velocity for a defined interval of concentrations 

and considering more species allows immediate comparison of their performances.  

Starting from the selection of plant species with superior purifying ability provided by Kim et al. (2018), a group 

of studies have been revised employing the methodology proposed. After the data collection phase, the removal 

rates described were calculated using Eq(1), Eq(2) and Eq(3), and additional information concerning mainly the 

plant metabolism and the environmental conditions of the experimentations were collected. The idea was to 

produce a review, in the form of a database, with comparable data directly usable for designing phytoremediation 

interventions in real environments. The results of this application will be presented in the following section, 

together with an example that illustrates how the database can be used.  

3. Results 

The application of the methodology proposed led to the definition of the structure of a database containing, for 

each test examined, general information regarding the study, the essential data required for the application of 

the methodology, the results of the calculations of the four removal rates defined, and additional details 

potentially useful to refine the analysis in a second phase. All the relevant database fields are reported in Figure 

1. They are arranged, for clarity, in four sets.  

 
Figure 1: Fields addressed in the database obtained applying the proposed methodology to a selection of 

experimental tests. 

 

573



Starting from the left side, the first set of fields provide general information about the tests as the species and 

the pollutant addressed. It is to note that peculiarities concerning mainly the species metabolism are addressed 

in a specific field as it is well known that they can significantly influence the VOC abatement. 

The second set reports all the essential numerical data required for applying the methodology. These data are 

the initial and the final pollutant concentration measured in the chamber, the duration of the experiment, the 

plant area (A) where removal takes place, and the chamber volume. As the idea is to consider the entire plant 

as a system, the total plant area includes, when applicable, both the leaf and root zone area to include the 

contribution of all the VOC removal pathways. Finally, it is important for each test to specify if they involved the 

entire plant, the aerial part or the root zone. This element evidently gives to the results obtained their actual 

value. 

The four removal rates values calculated starting from these data are reported in the third section of the 

database, and they provide a first harmonised indication of the actual abatement capacity of the different species 

concerning a specific contaminant.  

As environmental conditions are known to play a significant role in VOC removal, information concerning 

temperature, relative humidity and light conditions are noted in the last part of the database, together with basic 

information about the instrumentations employed in the tests. 

It is to note that, due to the lack of standardised methodologies, all this information is not always provided in the 

studies revised. Therefore, in the database were included only the tests where all the fields in the second and 

third sets could be filled. The resulting set of records formed the first version of the database. 

An example of how this database can be used is presented in the following section. The idea is to demonstrate 

how to select the best performing species to remediate formaldehyde, the most studied and common indoor 

contaminant, using the methodology proposed.  

A selection of the database is presented in Table 1. For the sake of brevity, this selection exclusively concerns 

studies referred to the contaminant of interest performed on entire specimens and in conditions of light. Different 

metabolisms have not been observed for this selection. Moreover, only the fields concerning the application of 

the methodology have been reported (the temperature field was added as this datum was employed to perform 

the necessary unit conversions).  

Table 1: Extract from the database for formaldehyde, the studies reported were performed on entire 

specimens and in light conditions.  

Species Fatsia  

japonica 

Ficus 

benjamina 

Scindapsus  

aureus  

Syngonium 

podophyllum 

Chlorophytum 

elatum vittatum  

Dracaena 

messangeana 

Reference Kim et al. 

(2008) 

Kim et al. 

(2008) 

Wolverton and 

McDonald 

(1982) 

Wolverton and 

McDonald 

(1982) 

Wolverton et al. 

(1984) 

Wolverton et 

al. (1989) 

Species 

peculiarities  

- - - - - - 

C0 (μg/m3) 2471.52 2471.52 23066.47 20638.42 17254.04 24144.27 

Cf (μg/m3) 346.01 271.87 4856.1 2185.24 2464.86 7243.28 

t (h) 5 5 24 24 6 24 

A (m2) 0.35 0.42 0.64 0.64 0.71 0.72 

V (m3) 1 1 0.39 0.39 0.4 0.88 

k1 (1/h) 0.39 0.44 0.06 0.09 0.32 0.05 

k0 (μg/m3h) 425.1 439.93 758.77 768.88 2464.86 704.21 

η1 (m/h) 1.13 1.06 0.04 0.06 0.18 0.06 

η0 (μg/m2h) 1222.71 1051.58 458.34 464.31 1392.5 862.55 

T (C°) 23 ± 2 23 ± 2 28.3 28.3 28.3 30 ± 1 

 

It can be seen, analysing the results obtained, that the removal rates per unit leaf area values can give a first 

indication of the different performances of the species in removing the contaminant of interest from indoor air. It 

can be moreover proven that this extract gives an idea of the differences between the experiments analysed, 

proving the necessity to define an appropriate approach for their evaluation. 

In order to select the best performing species in removing indoor formaldehyde, the overall abatement velocities 

(as defined in Eq(4)) regarding the revised studies have been calculated for a reasonable interval of 

concentrations using the data presented in Table 1. The entire plant area and chamber volume ratio A/V (1/m) 

is considered equal to one to allow an adequate comparison. The curves obtained for the six species revised 

are reported in Figure 2.  

574



It can be noticed that the curves offer a clear indication of the abatement performance of each species at 

different concentrations and that they can be considered a practical tool to select the best species knowing the 

average initial VOC concentration in a specific indoor environment.  From the results presented below, it is clear 

that Fatsia japonica is, on the whole, the best performing plant species in remediating the pollutant of interest. 

Clorophytum elatum vittatum and Ficus benjamina are likewise interesting species to consider, but the 

dissimilarities in their performances have to be taken into account. Considering that the average VOC 

concentrations detected indoors are usually low, Ficus benjamina should be more suitable for designing plant-

based remediation interventions in indoor environments than Clorophytum. It is evident, in fact, that this last 

species performs better at concentrations that are not typical in indoor environments.  

 

 

Figure 2: Formaldehyde abatement velocity curves for the studies revised in the methodology application. 

4. Conclusions 

Even though the attention concerning indoor air phytoremediation is rising, to date, the experimentations in 

controlled chambers to define the VOC abatement capacity of different species and the reviews available do 

not often provide comparable and usable results to design plant-based mitigation interventions in real 

environments.  

For this purpose, a new methodology has been proposed in this work. Considering that the overall VOC plant 

abatement is neither a zero nor a first-order process, but rather a hybrid of the two, an abatement remediation 

velocity (expressed in μg/m3h) has been defined, approaching the abatement analogously to a biological 

process. This parameter provides a clear indication of the actual performance of the species to remediate a 

specific contaminant at different concentrations.  

The methodology has been applied to a group of experimental studies identified as concerning the species with 

superior VOC purifying ability (it is to stress that this selection does not provide harmonisation of the abatement 

but individuates only the best removal obtained per test). This application led to the construction of a database, 

that can be considered a first tool to help a robust quantitative design of plant-based mitigation interventions in 

real environments. As a case study, an example of the usage of this database (for which only relevant fields 

have been shown) has been provided.  

575



The methodology and the review of previous studies want to provide a robust basis to design plant-based 

mitigation interventions in real indoor settings. The proposed approach allows the assessment and the 

comparison of the plant abatement performances obtained using different experimental protocols, and the 

review provides a structure that can be considered a step ahead for the definition of standardised protocols for 

the experimental tests as it includes all the essential elements required to calculate the VOC removal in a 

harmonised way. Evidently, further studies concerning the VOC removal mechanisms of different plant species 

could help refine the methodology, and the database produced can be extended, including more studies and 

fields.  

References 

Bernstein J.A., Alexis N., Bacchus H., Bernstein I.L., Fritz P., Horner E., Li N., Mason S.I., Nel A., Oulette J., 

Reijula K., Reponen T., Seltzer J.M., Smith A., Tarlo S.M., 2008, The health effects of nonindustrial Indoor 

Air Pollution, American Academy of Allergy, Asthma & Immunology, 121(3), 585-591. 

Dela Cruz M., Christensen J.H., Dyrauge Thomsen, Muller R., 2014, Can ornamental potted plants remove 

volatile organic compounds from indoor air? – A review, Environmental Science and Pollution Research, 

21(24), 13909-13928. 

Di Talia V., Antonioni G., 2021, A Model for the Evaluation of VOCs Abatement by Potted Plants in Indoor 

Environments, Chemical Engineering transactions CEt, 86, 415-420. 

Gong Y, Zhou T, Wang P, Lin Y, Zheng R, Zhao Y, Xu B, 2019, Fundamentals of Ornamental Plants in Removing 

Benzene in Indoor Air, Atmosphere, 10(4), 221. 

Han K., Ruan L., 2020, Effects of indoor plants on air quality: a systematic review, Environmental Science and 

Pollution Research, 26, 16019–16051.  

Kim K.J., Mi J.K., Jeong S.S., Eun H.Y., Son K., Kays S., 2008, Efficiency of Volatile Formaldehyde Removal 

by Indoor Plants: Contribution of Aerial Plant Parts versus the Root Zone, Journal of the American Society 

for Horticultural Science, 133, 521-526.  

Kim K.W., Khalekuzzaman M.D., Suh J.N., Hyeon J.K., Shagol C., Kim H.H., Kim H.J., 2018, Phytoremediation 

of volatile organic compounds by indoor plants: a review, Horticulture, Environment, and Biotechnology, 

59(10),143-157. 

Moschandreas D., Stark J., 1978, The GEOMET indoor-outdoor air pollution model, U.S. Environmental 

Protection Agency, Washington, D.C., EPA/600/7-78/106. 

Soreanu G., Dixon M.A., Darlington A.B., 2013, Botanical biofiltration of indoor gaseous pollutants - A mini-

review, Chemical Engineering Journal, 229, 585-594. 

Sriprapat W., Thiravetyan P., 2013, Phytoremediation of BTEX from Indoor Air by Zamioculcas zamiifolia, Water, 

Air, & Soil Pollution, 224, article number: 1482. 

Suárez-Cáceres G. P., Fernández-Cañero R., Fernández-Espinosa A.J., Rossini-Oliva S., Franco-Salas A., 

Pérez-Urrestarazu L., 2021, Volatile Organic Compounds Removal by Means of a Felt-Based Living Wall to 

Improve Indoor Air Quality, Atmospheric Pollution Research, 12(3), 224–229. 

Sundell J., 2004, On the history of indoor air quality and health, Indoor Air, 14 (Suppl 7), 51-58. 

Wolverton B.C., Mcdonald R.C, Watkins E.A., 1984, Foliage Plants for Removing Indoor Air Pollutants from 

Energy-Efficient Homes, Economic Botany, 38(2), 224-228. 

Wolverton B.C., Mcdonald R.C, 1982, Foliage Plants for Removing Formaldehyde from Contaminated Air Inside 

Energy-Efficient Homes and Future Space Stations, NASA TM-84674 

Wolverton B.C., Johnson A., Bounds K., 1989, Interior landscape plants for indoor air pollution abatement, final 

report, Document ID: 19930073077. 

Wood R.A., Burchett M.D., Alquezar R., Orwell R.L., Tarran J., Torpy F., 2006, The potted-plant microcosm 

substantially reduces indoor air VOC pollution:1.office field study, Water, Air and Soil Pollution, 175(1), 163-

180. 

 

576


	158ditalia.pdf
	A Methodology for the evaluation of the VOC Abatement Capacity of Different Species of Potted Ornamental Plants in Phytoremediating Indoor Air