Study of biochemical factors in assessing air pollution tolerance index of selected plant species in and around Durgapur industrial belt, India

Assessment of air pollution tolerance and anticipated performance index of roadside trees in urban and semi-urban regions

Rapid urbanization and rising vehicular population are the main precursors in increasing air pollutants concentration which negatively influences the surrounding ecosystem. Roadside plants are frequently used as the barrier against traffic emissions to minimize the effects of air pollution. They are, however, vulnerable to various contaminants, and their tolerance capacity varies. This necessitates a scientific inquiry into the role of roadside plantations in improved urban sprawl planning and management, where chosen trees could be cultivated to reduce air pollution. The present study assesses biochemical and physiological characteristics to evaluate the air pollution tolerance index (APTI) in Ranchi, Jharkhand. The anticipated performance index (API) was assessed based on calculated APTI and socioeconomic characteristics of a selected common tree species along the roadside at different sites. According to APTI, Mangifera indica and Eugenia jambolana were the most tolerant species throughout all the sites, while Ficus benghalensis and Ficus religiosa were intermediately tolerant towards air pollution. The one-way ANOVA shows no significant variation in APTI throughout all the sites. The regression plot shows the positive correlation of APTI with ascorbic acid among all the parameters. According to API, the Mangifera indica, Eugenia jambolana Ficus religiosa and Ficus benghalensis were excellent and best performers among all the sites. So, the air pollution-resistant tree species can be recommended for roadside plantations for the development of green belt areas in urban regions.

Assessment of air pollution tolerance index (APTI) and anticipated performance index (API) of selected roadside plant species for the green belt development at Ratnagiri City in the Konkan region of Maharashtra, India

Small towns are becoming hotspots of pollution due to industrial, urbanisation, and domestic activities. Air pollution affects human health and it is also responsible for physiological changes in plants. Green belt development programmes are cost-effective for the minimisation of air pollution. In the present study, to calculate air pollution tolerance index (APTI) and anticipated performance index (API), samples of 25 plant species were collected from each area i.e. the industrial (I), urban (U), and rural (R) areas and analysed for different parameters. Amongst all three areas, APTI of Artocarpus heterophyllus (46.74), Calotropis gigantea (43.63), and Bauhinia racemose (42.11) have shown the highest values and these plants can act as an inhibitor of air pollution. Also, the APTI of Ocimum tenuiflorum has found to be the lowest (12.05, 11.32, 12.86) as compared to other plant species amongst the three areas. Statistical analysis reveals that values of R² are consistent in case of total chlorophyll (TC) and ascorbic acid (AA). API index showed the efficiency of Calotropis gigantea (excellent), Artocarpus heterophyllus (very good), and Mangifera indica (very good) for the green belt development around the selected areas. It is recommended to plant above-mentioned plant species along the roadside by considering their air pollution tolerance ability and medicinal as well as economic importance. Furthermore, it is suggested to plant species of Artocarpus heterophyllus (jackfruit) and Mangifera indica (Alphonso mango) which will generate income source for the local government bodies (Ratnagiri Municipal Council), as the fruits and wood of these plants can be exported and sold.

Estimation of air pollution tolerance and anticipated performance index of roadside plants along the national highway in a tropical urban city

One of the most serious environmental issues is air pollution. Unlike other environmental concerns, this form of pollution is extremely challenging to regulate. The greenery of roadside trees plays a significant role in air purification and pollutant absorption, therefore helping to mitigate environmental pollution. Several plants can absorb and store toxins in their leaves from the atmosphere. Green plants have the potential to work as sinks and filters for air pollutants. Green belt development along national highways is a cost-effective and environmentally sustainable method of reducing air pollution. Sensitive and tolerant plants against air pollution can be identified by evaluating their air pollution tolerance index (APTI) and anticipated performance index (API) values. In this study, the susceptibility level of plant species to air pollution was assessed using APTI and API. The four parameters on which APTI depends are ascorbic acid content, total chlorophyll content, relative water content, and leaf extract pH. For the estimation of API, the plant's biological and socioeconomic factors like tree habit, canopy structure, type, size, texture, and hardness of the plant are also assessed. These parameters were determined and incorporated into a formula that represents the APTI and API of plants. Moreover, multilinear regression modeling was performed using a Statistical Package for the Social Sciences (SPSS, V25) and found that pH and ascorbic acid content in plant leaves have a significant role in the calculation of APTI and tolerance potential of plants. Therefore, APTI was assessed with seventeen plant species that are abundant in the area along the national highway in Kanpur, Uttar Pradesh, from Jan to Mar 2020. The APTI showed that Saraca asoca was the most resistant to air pollution, whereas Vachellia nilotica was the most sensitive. In addition, plants with higher APTI can also be used to reduce air pollution, while plants with lower APTI can be utilized to monitor air pollution. Based on the calculated API score, it is found that Ficus elastica (% score > 90) is the best option for green belt development. Urban local body (ULB) can also adopt Ficus religiosa, Saraca asoca, and Aucuba japonica (having % a grade score of 80-90) for mitigation of air pollution. The study indicates that plantations of tolerant species are useful for biomonitoring and developing green belts on and along national highways.

Prediction models for evaluating the impacts of ambient air pollutants on the biochemical response of selected tree species of Haridwar, India

This study aimed to assess the spatio-temporal impact of selected ambient air pollutants (SO₂, NO₂, PM₁₀, and PM_2.5) on the biochemical response of four tree species including Neem (Azadirachta indica), Mountain cedar (Toona ciliate), Bottlebrush (Callistemon citrinus), and Guava (Psidium guajava) in the province of Haridwar City, Uttarakhand, India. The study was performed in 2020 and 2021 over three selected sites (S1: institutional; S2: industrial; and S3: urban). Purposely, seasonal data of ambient air pollutants and biochemical parameters (ascorbic acid, carotenoid, chlorophyll, pH, relative water content, and dust load) of selected tree species were collected and analyzed using multiple linear regression (MLR) tool to develop prediction models. The results indicated that biochemical parameters of all tree species were negatively impacted by the polluted ambient air quality in the industrial and urban (S2 and S3) sites as compared to the non-polluted institutional (S1) site. The models were characterized by high prediction performance as indicated by the coefficient of determination (R²) values greater than 0.80. Moreover, A. indica was found to be more 'tolerant' based on the air pollution tolerance index (APTI) followed by T. ciliate, P. guajava, and C. citrinus. Similarly, the anticipated performance index (API) was reported higher for A. indica (75 to 81.25%) followed by T. ciliate (68.75 to 75.00%), P. guajava (56.25%), and C. citrinus (37.50%), respectively. This study revealed that the selected tree species are being negatively impacted by the induced pollutant exposure in the urban and industrial region of Haridwar, India which needs sufficient mitigation measures to conserve their diversities.

Screening of Plant Species Response and Performance for Green Belt Development: Implications for Semi-Urban Ecosystem Restoration

Screened plant species with potential for green belt development can act as eco-sustainable tools for restoring the polluted ecosystem. Eight plant species from two study locations in Ado-Odo, Ota, Ogun State, Nigeria, were examined to identify their air pollution response and performance by deploying two air pollution indices, namely air pollution tolerance index (APTI) and anticipated performance index (API). APTI results identified all screened plants as sensitive species suitable as bio-indicators of air pollution, with Ficus auriculata (2.42) common to the non-industrial location being the most sensitive. API scores categorized Ficus auriculata (56.25%) as a moderate performer, while Syzygium malaccense (75%) and Mangifera indica (75%) were identified as very good performers, suitable for green belt development. The relationship between each biochemical parameter with APTI was investigated using regression analysis and two-way analysis of variance. The model result showed a significant relationship between each biochemical parameter with APTI, and relative water content had the highest influence on APTI (R2 = 0.99436). Both indices (APTI and API) are suitable for screening and recommending native plant species for cultivation in the polluted environment, thus promoting ecological restoration. Hence, Syzygium malaccense, Mangifera indica and Ficus auriculata, respectively, were recommended for green belts design. Further intensive screening to identify tolerant species and best to excellent performer’s trees suitable for restoring the ecosystem is advised.