RESEARCH ARTICLE

Comparative study of Air Pollution Tolerance Index of selected plant species in Urban and Industrial Polluted area in Durg District

Ashwani Dewangan* and Anshudeep Khalkho

Department of Botany, Bharti Vishvavidyalaya Durg, (C.G.) India.

*Corresponding Author Email- ashwanidewangan307@gmail.com

Introduction

Air pollution is a growing concern in both urban and industrial areas of Durg district, posing significant threats to human health, ecosystems, and biodiversity. Urbanization and industrialization have led to increased emissions of pollutants, including particulate matter, nitrogen oxides, sulfur dioxide, and volatile organic compounds. Plants play a crucial role in mitigating air pollution through phytoremediation, a process where plants absorb, accumulate, and detoxify pollutants. However, not all plant species are equally tolerant to air pollution.

Plants are useful sensors of air quality, giving early warning of pollution trends (Wagh et al., 2006). Their large leaf surface area captures, absorbs, and accumulates air pollutants, thereby lowering atmospheric pollution levels (Escobedo et al., 2008), although this ability varies by species (Hove et al., 1999). Urban trees improve air quality by increasing the absorption of gases and particles (McPherson et al., 1994). Among plant structures, leaves are the most sensitive to air pollution and environmental variables (Lalman and Singh, 1990). Plants remove air pollutants via three primary mechanisms: particle deposition, leaf absorption, and aerosol collection on leaf surfaces (Prajapati and Tripathi, 2008). Researchers use the air pollution tolerance index to gauge how plants react to air pollution. Different plant species exhibit varied degrees of tolerance rather than uniform responses. Plants with higher index values have better pollution tolerance and can efficiently filter or absorb pollutants, whilst those with lower values have less tolerance and may act as pollution level indicators. Vehicle exhaust has been shown in studies to have both apparent and unseen impacts on roadside plants (Joshi and Swami, 2007). Pollutants such as SO₂, NO_x, SPM, and RSPM have been shown to impair a variety of biological and physiological processes in plants and crops grown in polluted environments (Chauhan A. et al., 2010).

The present study of Air Pollution Tolerance Index (APTI) in Mangifera indica, Ficus relegiosa , Cassia fistula, Calotropis procera and Bambusa vulgari  is significant as it identifies plant species that can tolerate air pollution with more significance. APTI studies contribute to phytoremediation efforts, ecosystem health, and environmental conservation by selecting suitable plant species for pollution mitigation. Ultimately, APTI research supports sustainable development, improves air quality, and helps mitigate the impacts of climate change.

Material and Method

Study site

Durg district is one of the most densely populated districts in the Indian state of Chhattisgarh. Based on climate and topography, the state of Chhattisgarh is divided into 3 agro-climatic zones. The study selected five plant species based on their abundance, distribution, and relevance to urban landscaping. The species were identified and authenticated from the Borai region (industrial sites) and near Durg city (urban sites) by a senior and a guide. Among five species, two are tree-like, two are shrub-like, and one is a monocot perennial, so a wide comparative data set can be obtained from the study to better plan this plant in urban plantations.

Biochemical Parameters

The following biochemical parameters were analyzed:

1. pH: Measured using a pH meter.

2. Relative Water Content (RWC): Calculated using the formula: RWC =   (Fresh weight - Dry weight) / Fresh weight × 100.

3. Chlorophyll Content: Estimated using spectrophotometry.

4. Ascorbic Acid Content: Determined using titration or HPLC.

Air Pollution Tolerance Index (APTI)

The Air Pollution Tolerance Index (APTI) is a widely used metric to assess the tolerance of plant species to air pollution. APTI is calculated based on four biochemical parameters: pH, relative water content, chlorophyll, and ascorbic acid. These parameters reflect the plant's physiological and biochemical responses to air pollution stress.

APTI Calculation

The APTI was calculated using the formula: APTI = [A × (pH) + B × (RWC) + C × (Chlorophyll) + D × (Ascorbic acid)], where A, B, C, and D is constants.

Results and Discussion

Mangifera indica, commonly known as the mango tree, shows a distinct progression in its APTI values across different environmental conditions. The data indicate a gradual increase from 7.5 ± 0.6 in the control region to 10.09 ± 0.73 and 11.28 ± 0.75 in urban regions, suggesting a moderate ability to adapt to pollution stress. However, the trend shows a slight decline in industrial regions with values such as 10.06 ± 0.72 and 9.62 ± 0.71, before stabilizing at 10.20 ± 0.75 (Table 1), indicating that while Mangifera indica can tolerate elevated pollution levels, its adaptability might be less robust in highly polluted industrial areas compared to urban environments. This pattern highlights its potential as a viable species for urban plantation but demonstrates limitations under severe industrial pollution, requiring further strategies for optimized environmental management.

Ficus religiosa demonstrates a progressive increase in its APTI values from control to urban and industrial regions. This trend underscores its ability to adapt to and tolerate higher pollution levels, making it a suitable candidate for urban plantations and environmental management strategies.

Ficus religiosa, commonly known as the sacred fig, was analyzed across various environments to examine its pollution tolerance index (APTI) values; data from control, urban, and industrial regions showed mean ± standard deviation values. The control region presented the lowest APTI value of 10.50 ± 0.45, serving as a baseline, while urban regions showed a gradual increase from 11.61 ± 0.50 in Urban Region 1 to 12.50 ± 0.60 in Urban Region 3, indicating moderate adaptation to pollution. Industrial regions had the highest APTI values, ranging from 13.80 ± 0.68 in Industrial Region 3 to 14.51 ± 0.70 in Industrial Region 1 (Table 2), demonstrating significant tolerance or adaptation mechanisms under heavy pollution. The progression of APTI values from control to urban and industrial regions underscores the remarkable adaptability of Ficus religiosa, making it a valuable species for urban plantation and environmental management strategies.

Calotropis procera, commonly known as the madar or milkweed, shows a notable increase in its APTI values across control, urban, and industrial regions, reflecting its adaptability to varying pollution levels. Starting with a baseline value of 11.0 ± 1.2 in the control region, its APTI values show an upward trend in urban areas, increasing to 12.3 ± 1.5 and 12.0 ± 1.4, before reaching 12.5 ± 1.6 in Urban Region 3 (Table 3). This growth suggests a moderate ability to adapt to urban pollution stress effectively.

In industrial regions, Calotropis procera demonstrates even higher tolerance levels, with APTI values climbing to 13.78 ± 1.8 in Industrial Region 1 and stabilizing slightly at 13.50 ± 1.9 and 13.0 ± 2.0 in subsequent regions. This pattern underscores its robust mechanisms for coping with elevated pollution, making it an exceptional candidate for industrial and urban plantation initiatives. Its consistent performance across highly polluted environments highlights its potential role in environmental management and urban greening strategies, especially in areas that require resilient species capable of thriving under extreme stress.

Cassia fistula, commonly known as the golden shower tree, shows a relatively stable progression in its Air Pollution Tolerance Index (APTI) across regions, reflecting its adaptation to pollution stress in both urban and industrial environments. Starting with a baseline APTI value of 17.0 ± 0.50 in the control region, the data show a slight increase in urban areas, with values of 17.1 ± 0.60 and 17.2 ± 0.60, reaching 18.2 ± 0.70 in Urban Region 3 (Table 4). This indicates a moderate ability of Cassia fistula to cope effectively with urban pollution stress.

Table 1: Table 1. Biochemical Parameters and APTI of Mangifera indica Across Control, Urban, and Industrial Regions

Table 2: Biochemical Parameters and APTI of Ficus religiosa Across Control, Urban, and Industrial Regions

Table 3: Biochemical Parameters and APTI of Calotropis procera Across Control, Urban, and Industrial Regions

Table 4: Biochemical Parameters and APTI of Cassia fistula Across Control, Urban, and Industrial Regions

Table 5: Biochemical Parameters and APTI of Bambusa vulgaris Across Control, Urban, and Industrial Regions

Table 6: Comparative APTI Values of plant species