45 Banko Janakari, Vol 35 No. 1Banko Janakari, Vol 35 No. 1, 2025 Pp 45-61https://doi.org/10.3126/banko.v35i1.73301 Effects of dust pollution on leaf morphology and chlorophyll content: A comparative study across two seasons in Biratnagar, Nepal U. Shrestha 1, S. Rijal 1, M. K. Chettri 1, B. D. Acharya 1, M. R. Paudel 2, A. Shrestha 2, P. Adhikari 2, A. Devkota 2* The effect of dust on leaf morphology and chlorophyll content in industrial, roadside, residential, and campus areas during the winter (January) and monsoon (June) season of 2024 was investigated. The highest dust load on the leaves of Tectona grandis was recorded in industrial areas during the winter season. The greatest leaf area reduction was observed in Azadirachta indica (13.25%) in winter and Citrus maxima (14.32%) in the monsoon season. The specific leaf area (SLA) of Ficus religiosa decreased by 20.48% in winter, and that of Nephelium litchi decreased by 28.46% in monsoon, particularly in industrial areas, likely due to their dust-trapping capacity and stress tolerance. Total chlorophyll was mostly reduced in polluted areas (industrial, roadside areas) in the winter season. During the studied seasons, chlorophyll-a ranged from 0.04 to 2.56 mg/g, chlorophyll-b ranged from 0.66 to 2.56 mg/g, and total chlorophyll ranged from 0.13 to 3.08 mg/g. Both chlorophyll-a and chlorophyll-b showed greater reduction during the monsoon season compared to winter. Less reduction in chlorophyll-a was observed in Ficus benghalensis, Ficus religiosa, Mangifera indica, Neolamarckia cadamba, and Syzygium cumini. But the species like Artocarpus heterophyllus, Citrus maxima, Syzygium cumini, and Mangifera indica exhibited less reduction in chlorophyll-b. The chlorophyll a:b ratio was generally higher during the winter season, particularly in the campus area (a less polluted site), whereas the ratio was reduced in more polluted areas. Physiological characteristics were more affected by dust accumulation than morphological characteristics. Plant species like Artocarpus heterophyllus, Ficus benghalensis, Ficus religiosa, Mangifera indica, Neolamarckia cadamba, Nephelium litchi and Psidium guajava showed comparatively less impact from dust, indicating their potential use in minimizing air pollution and enhancing urban green spaces. Key words: Chlorophyll ratio; Dust; Leaf area; Plant species; Specific leaf area (SLA). Air pollution, a pervasive issue in urban and industrial areas, consists of various pollutants such as particulate matters (PMs), gases, and heavy metals that adversely affect living organisms, including plants (Sharma et al., 2007; Jitin & Jain, 2014). Leaves which are the primary site for photosynthesis, are the most exposed part of a plant and are often the first to exhibit signs of damage when exposed to pollutants (Prajapati & Tripathi, 2008). Air pollution impacts plants through the accumulation of dust and particulate matter on leaf surfaces. Due to their large surface area, airborne pollutants get trapped and block stomata function, reduce photosynthetic efficiency, and alter metabolic processes (Javanmard et al., 2019). Studies have shown that increased dust accumulation lead to higher relative water content (RWC) and ascorbic acid levels, while simultaneously reducing chlorophyll content and leaf pH (Pandey et al., 2015; Bharti et al., 2017; Sapkota & Shrestha, 2024). One of the most 1 Department of Botany, Amrit Campus, Tribhuvan University, Kathmandu 2 Central Department of Botany, Tribhuvan University, Kathmandu *Email: devkotaa@gmail.com Received: 30, December 2024 Revised: 30, March 2025 Accepted: 19, May 2025 Published: 30, May 2025 https://orcid.org/0009-0007-5272-2493 https://orcid.org/0009-0003-7485-2302 https://orcid.org/0009-0007-7710-371X https://orcid.org/0009-0004-0262-5861 https://orcid.org/0000-0002-1739-9228 https://orcid.org/0009-0005-0343-1740 https://orcid.org/0009-0000-8583-364X https://orcid.org/0000-0003-1065-3286 46 Banko Janakari, Vol 35 No. 1 Shrestha et al. common impacts of plant exposure to pollutants is a reduction in chlorophyll concentrations (Nithamathi & Indira, 2005), along with leaf yellowing, which consequently decreases the photosynthetic rate (Joshi & Swami, 2007). The ratio of chlorophyll-a to chlorophyll-b helps in the identification of changes in light perceptions in plants (Kushwaha et al., 2024). Specific leaf area (SLA) is the ratio of leaf area to its dry mass. It is an important morphological and functional trait that reflects a plant’s adaptability to its environmental conditions (Liu et al., 2018). SLA is closely related to photosynthesis, respiration, and biomass production. Changes in SLA due to environmental stressors indicate shifts in resource allocation and overall plant health. Additionally, leaf shape parameters, including leaf area, length, and width, serve as key indicators for evaluating the impact of air pollution on plant morphology and functioning (Wang et al., 2021). Understanding the extent of dust accumulation and its effects on leaf morphology is crucial for assessing the implications of air pollution on plant growth and development. This study aimed to investigate the impact of dust load on leaf macro morphology and chlorophyll content with the objective of identifying tolerant and sensitive plant species suitable for plantation in urban areas of the Terai region, Nepal. Materials and methods Study area The study was conducted in Biratnagar, located in Morang district, Koshi Province (26°28’60” N latitude and 87°16’60” E longitude). Biratnagar, is an industrial city in the eastern Terai region of Nepal. Located in the tropical zone, Biratnagar experienced temperature variations ranging from 9.76 °C in January to 33.58 °C in April. The highest recorded precipitation was 353 mm in September, while no rainfall was recorded in November during the period from 2019 to 2024 (Biratnagar station). According to the Department of Industry (DOI, 2022), a total of 302 industries were registered in Morang District in the fiscal year 2078/2079. The most polluted industrial areas were Budhiganga and Gidhaniya, surrounded by various industries like Swastika Jute Mills, Surya Chemical Pvt. Ltd, located within an aerial distance of 250 to 500 m (Figure 1). Roadside areas were Titariya, Ghinaghat and Malaya Road, which are road networks connected to Biratnagar. Residential areas were from the Rani temple area nearer to the Biratngar custom office. The Mahendra Morang Multiple Campus, Biratnagar was considered as relatively less polluted area. The study was conducted in Biratnagar, located in Morang district, Koshi Province (26°28'60" N latitude and 87°16'60" E longitude). Biratnagar, is an industrial city in the eastern Terai region of Nepal. Located in the tropical zone, Biratnagar experienced temperature variations ranging from 9.76 °C in January to 33.58 °C in April. The highest recorded precipitation was 353 mm in September, while no rainfall was recorded in November during the period from 2019 to 2024 (Biratnagar station). According to the Department of Industry (DOI, 2022), a total of 302 industries were registered in Morang District in the fiscal year 2078/2079. The most polluted industrial areas were Budhiganga and Gidhaniya, surrounded by various industries like Swastika Jute Mills, Surya Chemical Pvt. Ltd, located within an aerial distance of 250 to 500 m (Figure 1). Roadside areas were Titariya, Ghinaghat and Malaya Road, which are road networks connected to Biratnagar. Residential areas were from the Rani temple area nearer to the Biratngar custom office. The Mahendra Morang Multiple Campus, Biratnagar was considered as relatively less polluted area. Figure 1: Map of the study area (A=Nepal, B= Morang, C= Industrial and D= Roadside, residential and campus, Source: QGIS version 3.28) Study areas were categorized based on the average concentrations of particulate matter (PM), respirable suspended particles (RSP) and total suspended particles (TSP) (measured in μg/m³) recorded at different sites using Aeroqual Air Sampler, USA (Table 1). Figure 1: Map of the study area (A=Nepal, B= Morang, C= Industrial and D= Roadside, residential and campus, Source: QGIS version 3.28) 47 Banko Janakari, Vol 35 No. 1Shrestha et al. Study areas were categorized based on the average concentrations of particulate matter (PM), respirable suspended particles (RSP) and total suspended particles (TSP) (measured in μg/m³) recorded at different sites using Aeroqual Air Sampler, USA (Table 1). Sampling design Purposive sampling was conducted in January for winter and July for monsoon season of 2024 in Biratnagar, Morang district because ambient air quality during winter months mostly remains polluted due to dry weather conditions. Altogether 12 plant species (Table 2) were selected based on their availability and natural occurrence in the study area. Plant species were identified through direct field observations prior to sample collection. Secondary sources, including references books (Flora of Nepal) and the Tribhuvan University Central Herbarium (TUCH), were also consulted for accurate identification. Broad and mature leaves (25-30 samples per species) were collected using a pruner from approximately 2 meters above ground level to ensure the optimal dust accumulation and to standardize the average height of trees. For comparative study between polluted and less polluted campus areas, 12 plant species were found to be common between the industrial and less polluted campus areas, 10 species were common between the roadside and less polluted campus areas and only 4 plant species were recorded as common between residential and less polluted campus areas. Laboratory analysis Morphological characteristics Triplicate leaf samples were collected from each plant species. Leaf length, leaf width and leaf area of the respective plant species were measured using ImageJ Software version 1.54 (Hamal, 2023). Dust load Dust load on the leaves was measured following Prusty et al. (2005) protocol. First, three mature leaf samples of each species from each site were collected and weighed with dust (W1). The leaves were then thoroughly cleaned and weighed again (W2). The leaf area was calculated using ImageJ software version 1.54g (Hamal, 2023). The dust load accumulated on Table 1: Classification of study areas based on average concentrations of PM, RSP and TSP on the different sites (μg/m3) (mean± SD, n=60) Note: Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05) Sampling design Purposive sampling was conducted in January for winter and July for monsoon season of 2024 in Biratnagar, Morang district because ambient air quality during winter months mostly remains polluted due to dry weather conditions. Altogether 12 plant species (Table 2) were selected based on their availability and natural occurrence in the study area. Plant species were identified through direct field observations prior to sample collection. Secondary sources, including references books (Flora of Nepal) and the Tribhuvan University Central Herbarium (TUCH), were also consulted for accurate identification. Broad and mature leaves (25-30 samples per species) were collected using a pruner from approximately 2 meters above ground level to ensure the optimal dust accumulation and to standardize the average height of trees. Table 2: List of plant species collected from different sites SN Name of plant species Common name Family 1. Artocarpus heterophyllus Lam. Jackfruit Moraceae 2. Azadirachta indica A.Juss. Neem Meliaceae 3. Citrus maxima (Burm). Merr. Bhogate Rutaceae 4. Ficus benghalensis L. Bar Moraceae 5. Ficus religiosa L. Peepal Moraceae 6. Mangifera indica L. Mango Anacardiaceae 7. Neolamarckia cadamba (Roxb.) Bosser Kadam Rubiaceae 8. Nephelium litchi Steud Litchi Sapindaceae 9. Psidium guajava L. Guava Myrtaceae 10. Syzygium cumini (L.) Skeels Jamun Myrtaceae 11. Saraca ascosa (Roxb.) Wild. Ashoka Fabaceae 12. Tectona grandis L. f. Teak Lamiaceae For comparative study between polluted and less polluted campus areas, 12 plant species were found to be common between the industrial and less polluted campus areas, 10 species were common between the roadside and less polluted campus areas and only 4 plant species were recorded as common between residential and less polluted campus areas. Study area Category Locations PM1 PM2.5 PM10 RSP TSP Industrial Polluted Budhiganga and Gidhaniya 32.95±3.86d 46.20±4.63d 75.70±12.27d 56.05±6.23c 86.68±17.22d Roadside Polluted Titariya, Ghinaghat and Malaya 26.71±0.99c 34.17±1.14c 64.37±1.92c 43.09±1.55b 80.62±2.38c Residential Moderately Polluted Rani Temple 21.67±1.85b 25.28±1.42b 36.77±2.30b 28.39±1.83 a 34.28±2.60a Campus area Less Polluted Mahendra Morang campus 17.10±0.99a 22.78±1.18 a 31.87±1.89 a 28.87±1.76 a 42.84±2.27b Table 1: Classification of study areas based on average concentrations of PM, RSP and TSP on the different sites (μg/m3) (mean± SD, n=60) Note: Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05) Sampling design Purposive sampling was conducted in January for winter and July for monsoon season of 2024 in Biratnagar, Morang district because ambient air quality during winter months mostly remains polluted due to dry weather conditions. Altogether 12 plant species (Table 2) were selected based on their availability and natural occurrence in the study area. Plant species were identified through direct field observations prior to sample collection. Secondary sources, including references books (Flora of Nepal) and the Tribhuvan University Central Herbarium (TUCH), were also consulted for accurate identification. Broad and mature leaves (25-30 samples per species) were collected using a pruner from approximately 2 meters above ground level to ensure the optimal dust accumulation and to standardize the average height of trees. Table 2: List of plant species collected from different sites SN Name of plant species Common name Family 1. Artocarpus heterophyllus Lam. Jackfruit Moraceae 2. Azadirachta indica A.Juss. Neem Meliaceae 3. Citrus maxima (Burm). Merr. Bhogate Rutaceae 4. Ficus benghalensis L. Bar Moraceae 5. Ficus religiosa L. Peepal Moraceae 6. Mangifera indica L. Mango Anacardiaceae 7. Neolamarckia cadamba (Roxb.) Bosser Kadam Rubiaceae 8. Nephelium litchi Steud Litchi Sapindaceae 9. Psidium guajava L. Guava Myrtaceae 10. Syzygium cumini (L.) Skeels Jamun Myrtaceae 11. Saraca ascosa (Roxb.) Wild. Ashoka Fabaceae 12. Tectona grandis L. f. Teak Lamiaceae For comparative study between polluted and less polluted campus areas, 12 plant species were found to be common between the industrial and less polluted campus areas, 10 species were common between the roadside and less polluted campus areas and only 4 plant species were recorded as common between residential and less polluted campus areas. Study area Category Locations PM1 PM2.5 PM10 RSP TSP Industrial Polluted Budhiganga and Gidhaniya 32.95±3.86d 46.20±4.63d 75.70±12.27d 56.05±6.23c 86.68±17.22d Roadside Polluted Titariya, Ghinaghat and Malaya 26.71±0.99c 34.17±1.14c 64.37±1.92c 43.09±1.55b 80.62±2.38c Residential Moderately Polluted Rani Temple 21.67±1.85b 25.28±1.42b 36.77±2.30b 28.39±1.83 a 34.28±2.60a Campus area Less Polluted Mahendra Morang campus 17.10±0.99a 22.78±1.18 a 31.87±1.89 a 28.87±1.76 a 42.84±2.27b Table 1: Classification of study areas based on average concentrations of PM, RSP and TSP on the different sites (μg/m3) (mean± SD, n=60) Note: Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05) Table 2: List of plant species collected from different sites 48 Banko Janakari, Vol 35 No. 1 Shrestha et al. the leaves was calculated using the formula given by Prusty et al. (2005): Statistical analysis All data calculation was done in MS Excel 2013, and statistical analyses were performed using IBM SPSS Statistics 20 version. One-way ANOVA was used to assess significant differences in the mean and percentage decrease of specific leaf area (SLA), leaf area, leaf length, leaf width, chlorophyll concentrations, and chlorophyll-a to chlorophyll-b ratio (a:b) among plant species from different study areas across the two seasons. Pearson’s Correlation test was performed to determine the relationship between dust load per leaf area, leaf morphology, and chlorophyll concentration reduction across both seasons. A scatter plot was drawn to visualize the relationships between selected pairs of variables. Results Dust load Dust load was comparatively higher in the winter season than in the monsoon (Figure 2), with industrial areas recording the highest average dust load accumulation, followed by residential, roadside, and campus areas in both seasons. Among the sample species, Tectona grandis in winter and Saraca asoca in the monsoon recorded the highest dust load in industrial areas with 12.29 mg/cm2 and 0.28 mg/cm2 respectively (Table 3). At roadside locations, Azadirachta indica exhibited the highest dust accumulation in both seasons, with 2.61 mg/ cm² in winter and 0.31 mg/cm² in the monsoon. Similarly, Saraca asoca (winter) and Mangifera indica (monsoon) recorded significantly higher dust load (p < 0.05) in residential areas, with 2.20 mg/ cm² and 0.21 mg/cm². Syzygium cumini in winter and Nephelium litchi in the monsoon recorded the highest dust load at 0.67 and 0.54 mg/cm2, respectively. The dust levels in residential areas were higher than those near the roads due to ongoing construction activities and increased vehicle movement. Laboratory analysis Morphological characteristics Triplicate leaf samples were collected from each plant species. Leaf length, leaf width and leaf area of the respective plant species were measured using ImageJ Software version 1.54 (Hamal, 2023). Dust load Dust load on the leaves was measured following Prusty et al. (2005) protocol. First, three mature leaf samples of each species from each site were collected and weighed with dust (W1). The leaves were then thoroughly cleaned and weighed again (W2). The leaf area was calculated using Image J software version 1.54g (Hamal, 2023). The dust load accumulated on the leaves was calculated using the formula given by Prusty et al. (2005): Specific leaf area (SLA) For the measurement of SLA, broad and mature leaf samples were selected, and their photographs were taken alongside a scale using Redmi mobile phone. Triplicate leaf samples were taken. The leaves were then oven-dried at 70 ˚C, and their dry weight was recorded using a digital balance (S303, 0.001g). The fresh leaf area was calculated using the ImageJ software version 1.54g. SLA for each leaf was determined according to Cornelissen et al. (1996). Chlorophyll content Disc of fresh leaves (weighing 0.09 g) were punched and kept in an Eppendorf tube containing 1 ml of DMSO4 (Dimethyl Sulfoxide) solvent immediately after collection. Chlorophyll content was determined according to Barnes et al. (1992) with slight modifications. Specifically, triplicate leaf disc samples from each species were immersed in DMSO4 and kept in an ice box for 24-48 hours to extract the chlorophyll and prevent chlorophyll degradation prior to laboratory analysis. After that, the solution along with leaf samples was kept in a water bath at 60-70 ˚C for 2-3 hours till the complete extraction of chlorophyll. The resulting extract was pipetted in a micro-plate using a micropipette, and the absorbance was measured at 665 nm and Laboratory analysis Morphological characteristics Triplicate leaf samples were collected from each plant species. Leaf length, leaf width and leaf area of the respective plant species were measured using ImageJ Software version 1.54 (Hamal, 2023). Dust load Dust load on the leaves was measured following Prusty et al. (2005) protocol. First, three mature leaf samples of each species from each site were collected and weighed with dust (W1). The leaves were then thoroughly cleaned and weighed again (W2). The leaf area was calculated using Image J software version 1.54g (Hamal, 2023). The dust load accumulated on the leaves was calculated using the formula given by Prusty et al. (2005): Specific leaf area (SLA) For the measurement of SLA, broad and mature leaf samples were selected, and their photographs were taken alongside a scale using Redmi mobile phone. Triplicate leaf samples were taken. The leaves were then oven-dried at 70 ˚C, and their dry weight was recorded using a digital balance (S303, 0.001g). The fresh leaf area was calculated using the ImageJ software version 1.54g. SLA for each leaf was determined according to Cornelissen et al. (1996). Chlorophyll content Disc of fresh leaves (weighing 0.09 g) were punched and kept in an Eppendorf tube containing 1 ml of DMSO4 (Dimethyl Sulfoxide) solvent immediately after collection. Chlorophyll content was determined according to Barnes et al. (1992) with slight modifications. Specifically, triplicate leaf disc samples from each species were immersed in DMSO4 and kept in an ice box for 24-48 hours to extract the chlorophyll and prevent chlorophyll degradation prior to laboratory analysis. After that, the solution along with leaf samples was kept in a water bath at 60-70 ˚C for 2-3 hours till the complete extraction of chlorophyll. The resulting extract was pipetted in a micro-plate using a micropipette, and the absorbance was measured at 665 nm and Specific leaf area (SLA) For the measurement of SLA, broad and mature leaf samples were selected, and their photographs were taken alongside a scale using Redmi mobile phone. Triplicate leaf samples were taken. The leaves were then oven-dried at 70°C, and their dry weight was recorded using a digital balance (S303, 0.001g). The fresh leaf area was calculated using the ImageJ software version 1.54g. SLA for each leaf was determined according to Cornelissen et al. (1996). Chlorophyll content Disc of fresh leaves (weighing 0.09 g) were punched and kept in an Eppendorf tube containing 1 ml of DMSO4 (Dimethyl Sulfoxide) solvent immediately after collection. Chlorophyll content was determined according to Barnes et al. (1992) with slight modifications. Specifically, triplicate leaf disc samples from each species were immersed in DMSO4 and kept in an ice box for 24-48 hours to extract the chlorophyll and prevent chlorophyll degradation prior to laboratory analysis. After that, the solution along with leaf samples was kept in a water bath at 60-70°C for 2-3 hours till the complete extraction of chlorophyll. The resulting extract was pipetted in a micro-plate using a micropipette, and the absorbance was measured at 665 nm and 648 nm using a microplate spectrophotometer (BioTek Epoch 2). Chlorophyll contents in the leaves were then calculated by using the formula given by Barnes et al. (1992). 648 nm using a microplate spectrophotometer (BioTek Epoch 2). Chlorophyll contents in the leaves were then calculated by using the formula given by Barnes et al. (1992). Where, V= volume of DMSO4 solvent, W= weight of fresh leaves used Statistical analysis All data calculation was done in MS Excel 2013, and statistical analyses were performed using IBM SPSS Statistics 20 version. One-way ANOVA was used to assess significant differences in the mean and percentage decrease of specific leaf area (SLA), leaf area, leaf length, leaf width, chlorophyll concentrations, and chlorophyll-a to chlorophyll-b ratio (a:b) among plant species from different study areas across the two seasons. Pearson’s Correlation test was performed to determine the relationship between dust load per leaf area, leaf morphology, and chlorophyll concentration reduction across both seasons. A scatter plot was drawn to visualize the relationships between selected pairs of variables. Results Dust load Dust load was comparatively higher in the winter season than in the monsoon (Figure 2), with industrial areas recording the highest average dust load accumulation, followed by residential, roadside, and campus areas in both seasons. Among the sample species, Tectona grandis in winter and Saraca asoca in the monsoon recorded the highest dust loads in industrial areas with 12.29 mg/cm2 and 0.28 mg/cm2 respectively (Table 3). At roadside locations, Azadirachta indica exhibited the highest dust accumulation in both seasons, with 2.61 mg/cm² in winter and 0.31 mg/cm² in the monsoon. Similarly, Saraca asoca (winter) and Mangifera indica (monsoon) recorded significantly higher dust loads (p < 0.05) in residential areas, with 2.20 mg/cm² and 0.21 mg/cm². Syzygium cumini in winter and Nephelium litchi in the monsoon recorded the highest dust loads at 0.67 and 0.54 mg/cm2, respectively. The dust levels in residential areas were higher than those near the roads due to ongoing construction activities and increased vehicle movement. Where, V= volume of DMSO4 solvent, W= weight of fresh leaves used Figure 2: Dust accumulation on leaves at different study areas across two seasons Figure 2: Dust accumulation on leaves at different study areas across two seasons Table 3: Dust load (mg/cm2) on leaves of different plant species comparing two seasons Plant species Industrial Roadside Residential Campus Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 1.05±0.10a 0.15±0.27abcd 0.48±0.09ab 0.09±0.01ab - - 0.26±0.10abc 0.15±0.04a Azadirachta indica 1.89±0.64a 0.20±0.02cd 2.61±0.43g 0.32±0.10c - - 0.23±0.09ab 0.14±0.01a Citrus maxima 9.60±0.89bc 0.05±0.01a 1.84±0.32efg 0.10±0.04ab - - 0.24±0.14ab 0.12±0.08a Ficus benghalensis 1.73±0.22a 0.12±0.01abc 0.88±0.19abcde 0.07±0.03a - - 0.63±0.21cd 0.10±0.03a Ficus religiosa 1.87±0.13a 0.11±0.00abc 1.71±0.32defg 0.11±0.01ab - - 0.27±0.06abc 0.13±0.03a Mangifera indica 6.99±0.94b 0.19±0.01bcd 1.56±0.29cdef 0.11±0.03ab 1.45±0.29bc 0.26±0.08b 0.40±0.10abcd 0.54±0.03b Neolamarckia cadamba 1.78±0.16a 0.11±0.01abc 0.70±0.19abcd 0.10±0.01ab 0.87±0.13ab 0.04±0.01a 0.16±0.05ab 0.04±0.01a Nephelium litchi 3.14±0.24a 0.14±0.07abc 0.66±0.12abcd 0.04±0.02a - - 0.13±0.03a 0.08±0.03a Psidium guajava 0.87±0.02a 0.15±0.10abcd 1.51±0.29bcdef 0.23±0.04bc 0.84±0.15ab 0.23±0.01ab 0.15±0.03ab 0.40±0.16b Syzygium cumini 2.89±0.23a 0.06±0.01ab 2.23±0.39fg 0.07±0.03a - - 0.67±0.08d 0.06±0.02a Saraca asoca 2.64±0.029a 0.28±0.01d - - 2.20±0.57c 0.21±0.07ab 0.33±0.04abcd 0.01±0.01a Tectona grandis 12.29±2.51c 0.21±0.05cd 1.57±0.41cdef 0.15±0.03ab - - 0.12±0.03a 0.05±0.02a F-value 14.12 2.48 5.16 3.40 4.25 2.98 2.53 7.14 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) Leaf area In winter, the leaf area ranged from 8.63 cm2 in Azadirachta indica at the industrial area to 194.98 cm2 in Tectona grandis at the roadside area. During the monsoon, the range was broader, with the lowest leaf area of 10.28 cm2 in Azadirachta indica in the industrial area and the highest of 904.58 cm2 in Tectona grandis in the campus area (Table 4). 0 0.5 1 1.5 2 2.5 3 3.5 Industrial area Road side Residential Campus area D us t l oa d (m g/ cm 2 ) Winter Monsoon Study areas 49 Banko Janakari, Vol 35 No. 1Shrestha et al. Leaf area In winter, the leaf area ranged from 8.63 cm2 in Azadirachta indica at the industrial area to 194.98 cm2 in Tectona grandis at the roadside area. During the monsoon, the range was broader, with the lowest leaf area of 10.28 cm2 in Azadirachta indica in the industrial area and the highest of 904.58 cm2 in Tectona grandis in the campus area (Table 4). The percentage of leaf area reduction was lower in industrial areas compared to campus areas during Table 3: Dust load (mg/cm2) on leaves of different plant species comparing two seasons both seasons. In the winter season, the greatest leaf area reduction was observed in Azadirachta indica (13.25%) at industrial, and in Neolamarckia cadamba at both roadside (12.65%) and residential (8.35%) areas. During the monsoon season, the maximum reduction in leaf area was recorded in Citrus maxima at industrial (14.32%) and Psidium guajava at both roadside (21.88%) and residential (13.91%) areas. Ficus religiosa showed the least leaf area reduction (0.42%) in industrial areas during the winter season (Figure 3). Table 4: Leaf area (cm2) of different plant species at study areas during two seasons Note: Data are expressed as Mean ± S.E and statistical analysis using one-way ANOVA for obtaining F and p-values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) Note: Data are expressed as Mean ± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) Table 4: Leaf area (cm2) of different plant species at study areas during two seasons Plant species Industrial Roadside Residential Campus Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 67.91±9.25cd 70.67±6.21bc 68.55±12.73cd 76.97±3.49ab - - 72.53±10.12de 78.23±3.58bc Azadirachta indica 8.63±0.23a 10.28±1.81a 8.71±0.22a 10.49±1.77a - - 9.95±0.18a 11.26±1.49a Citrus maxima 55.66±1.27bcd 48.89±7.10bc 58.44±5.34bc 51.43±2.64a - - 58.65±5.37bcd 57.02±2.65b Ficus benghalensis 89.64±8.60e 145.05±19.19e 86.10±5.66d 141.26±19.84bc - - 90.61±8.06e 161.46±17.48d Ficus religiosa 74.30±3.64de 51.40±2.59bc 66.39±6.41cd 51.05±2.60a - - 75.38±7.24de 54.81±3.18b Magnifera indica 60.36±5.04cd 81.71±10.73d 64.79±4.74c 86.08±8.98ab 65.86±13.20a 83.31±17.32a 67.02±4.69cd 92.35±10.33c Neolamarckia cadamba 114.48±2.76f 195.06±9.02f 106.82±4.35e 189.39±6.26c 112.00±3.84b 195.38±9.80b 122.32±4.31f 199.41±8.74e Nephelium litchi 39.92±4.98b 45.97±4.57b 41.13±2.75b 48.54±4.71a - - 41.74±3.16b 54.52±7.32b Psidium guajava 73.91±7.43de 74.71±12.50cd 71.61±3.96cd 67.00±12.01ab 70.74±4.84a 72.80±7.04a 74.61±7.15de 85.16±9.59c Syzygium cumini 50.78±4.69bc 71.75±3.42bc 56.72±6.90bc 70.95±5.59ab - - 58.17±4.41bcd 77.69±1.21bc Saraca asoca 51.34±4.30bc 55.01±5.20bc - - 48.41±2.37a 52.48±1.04a 51.95±4.13bc 59.42±3.67b Tectona grandis 174.13±12.35g 895.94±1.65g 194.98±7.85f 809.43±79.56d - - 196.57±7.35g 904.58±0.29f F-value 42.850 790.69 55.036 79.03 13.285 36.88 58.623 1029.69 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) The percentage of leaf area reduction was lower in industrial areas compared to campus areas during both seasons. In the winter season, the greatest leaf area reduction was observed in Azadirachta indica (13.25%) at industrial, and in Neolamarckia cadamba at both roadside (12.65%) and residential (8.35%) areas. During the monsoon season, the maximum reduction in leaf area was recorded in Citrus maxima at industrial (14.32%) and Psidium guajava at both roadside (21.88%) and residential (13.91%) areas. Ficus religiosa showed the least leaf area reduction (0.42%) in industrial areas during the winter season (Figure 3). Figure 2: Dust accumulation on leaves at different study areas across two seasons Table 3: Dust load (mg/cm2) on leaves of different plant species comparing two seasons Plant species Industrial Roadside Residential Campus Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 1.05±0.10a 0.15±0.27abcd 0.48±0.09ab 0.09±0.01ab - - 0.26±0.10abc 0.15±0.04a Azadirachta indica 1.89±0.64a 0.20±0.02cd 2.61±0.43g 0.32±0.10c - - 0.23±0.09ab 0.14±0.01a Citrus maxima 9.60±0.89bc 0.05±0.01a 1.84±0.32efg 0.10±0.04ab - - 0.24±0.14ab 0.12±0.08a Ficus benghalensis 1.73±0.22a 0.12±0.01abc 0.88±0.19abcde 0.07±0.03a - - 0.63±0.21cd 0.10±0.03a Ficus religiosa 1.87±0.13a 0.11±0.00abc 1.71±0.32defg 0.11±0.01ab - - 0.27±0.06abc 0.13±0.03a Mangifera indica 6.99±0.94b 0.19±0.01bcd 1.56±0.29cdef 0.11±0.03ab 1.45±0.29bc 0.26±0.08b 0.40±0.10abcd 0.54±0.03b Neolamarckia cadamba 1.78±0.16a 0.11±0.01abc 0.70±0.19abcd 0.10±0.01ab 0.87±0.13ab 0.04±0.01a 0.16±0.05ab 0.04±0.01a Nephelium litchi 3.14±0.24a 0.14±0.07abc 0.66±0.12abcd 0.04±0.02a - - 0.13±0.03a 0.08±0.03a Psidium guajava 0.87±0.02a 0.15±0.10abcd 1.51±0.29bcdef 0.23±0.04bc 0.84±0.15ab 0.23±0.01ab 0.15±0.03ab 0.40±0.16b Syzygium cumini 2.89±0.23a 0.06±0.01ab 2.23±0.39fg 0.07±0.03a - - 0.67±0.08d 0.06±0.02a Saraca asoca 2.64±0.029a 0.28±0.01d - - 2.20±0.57c 0.21±0.07ab 0.33±0.04abcd 0.01±0.01a Tectona grandis 12.29±2.51c 0.21±0.05cd 1.57±0.41cdef 0.15±0.03ab - - 0.12±0.03a 0.05±0.02a F-value 14.12 2.48 5.16 3.40 4.25 2.98 2.53 7.14 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) Leaf area In winter, the leaf area ranged from 8.63 cm2 in Azadirachta indica at the industrial area to 194.98 cm2 in Tectona grandis at the roadside area. During the monsoon, the range was broader, with the lowest leaf area of 10.28 cm2 in Azadirachta indica in the industrial area and the highest of 904.58 cm2 in Tectona grandis in the campus area (Table 4). 0 0.5 1 1.5 2 2.5 3 3.5 Industrial area Road side Residential Campus area D us t l oa d (m g/ cm 2 ) Winter Monsoon Study areas 50 Banko Janakari, Vol 35 No. 1 Shrestha et al. Specific leaf area (SLA) During the winter season, the SLA varied from 55.10 cm2/g in Syzygium cumini at the industrial area to 187.93 cm2/g in Azadirachta indica at the roadside area. In the monsoon season, the SLA ranged from 49.68 cm2/g in Ficus benghalensis at the roadside to 179.08 cm2/g in Citrus maxima at the campus area (Table 5). SLA was reduced in industrial areas and roadside compared to the campus area during both studied seasons (Figure 4). In industrial areas, Ficus religiosa showed the highest SLA reduction (20.48%) during Figure 3: Percentage (%) reduction in leaf area of different plant species in two seasons Specific leaf area (SLA) During the winter season, the SLA varied from 55.10 cm2/g in Syzygium cumini at the industrial area to 187.93 cm2/g in Azadirachta indica at the roadside area. In the monsoon season, the SLA ranged from 49.68 cm2/g in Ficus benghalensis at the roadside to 179.08 cm2/g in Citrus maxima at the campus area (Table 5). 0 5 10 15 20 25 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r ed uc tio n in le af a re a Seasons/Study areas Artocarpus heterophyllus Azadirachta indica Citrus maxima Ficus benghalensis Ficus religiosa Nephelium litchi Mangifera indica Neolamarckia cadamba Psidium guajava Syzygium cumini Saraca asoca Tectona grandis Figure 3: Percentage (%) reduction in leaf area of different plant species in two seasons Table 5: Specific leaf area (cm2/g) areas of different plant species at study areas during two seasons Table 5: Specific leaf area (cm2/g) areas of different plant species at study areas during two seasons Plant species Industrial Roadside Residential Campus Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 97.03±14.74b 140.50±10.58de 84.86±6.86abc 141.99±11.67de - - 111.71±34.70bc 143.13±11.06cde Azadirachta indica 150.28±1.69c 125.09±13.12cde 187.93±2.52f 117.73±15.52bcd - - 172.58±2.36d 129.88±22.24bcd Citrus maxima 102.99±2.50b 166.94±7.88e 123.49±15.71de 174.57±2.42e - - 110.57±6.51b 179.08±0.81e Ficus benghalensis 82.61±3.74b 61.38±5.49a 55.54±7.08ab 49.68±1.02a - - 86.13±1.45ab 68.50±7.97a Ficus religiosa 85.69±0.23b 86.18±7.08abc 76.09±28.76abc 92.32±7.15abc - - 114.70±18.47bc 101.49±4.15abc Magnifera indica 82.46±2.54b 87.83±23.67abc 55.06±1.99ab 56.18±3.78a 59.82±6.99a 85.46±22.74a 86.70±7.54ab 91.41±24.28ab Neolamarckia cadamba 146.60±10.77c 146.08±22.67de 130.95±1.43e 148.98±14.19de 96.66±4.13b 144.81±21.89a 153.61±5.92cd 154.72±18.65de Nephelium litchi 82.44±6.60b 116.20±6.92bcd 77.78±7.81abc 135.19±32.33cde - - 83.76±1.54ab 162.63±4.61de Psidium guajava 80.62±8.01b 73.94±26.90ab 89.22±1.00bc 71.92±25.55ab 88.94±4.72b 79.71±30.03a 93.50±2.95ab 81.49±29.91a Syzygium cumini 55.10±0.95a 80.06±6.50abc 49.68±3.10a 87.24±1.84ab - - 60.35±1.64a 89.50±1.45ab Saraca asoca 142.33±12.67c 138.71±9.44de - - 99.04±4.82b 140.81±4.62a 152.94±11.55cd 142.05±4.28cde Tectona grandis 105.00±3.37b 141.48±17.27de 94.84±7.27cd 150.87±6.26de - - 119.82±14.25bc 157.57±5.18de F-value 16.998 5.25 14.044 8.21 11.684 2.53 6.563 6.27 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) SLA was reduced in industrial areas and roadside compared to the campus area during both studied seasons (Figure 4). In industrial areas, Ficus religiosa showed the highest SLA reduction (20.48%) during winter, while Nephelium litchi showed the highest reduction (28.46%) during the monsoon. Similarly, Mangifera indica at roadside (35.55% and 30.57%) and Neolamarckia cadamba at residential areas (37.08% and 6.98%) recorded maximum SLA reduction during both seasons. Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) 51 Banko Janakari, Vol 35 No. 1Shrestha et al. Figure 4: Percentage (%) reduction in SLA of different plant species in two seasons An inverse relationship was observed between dust load and specific leaf area (SLA) (Figure 5), indicating that an increase in dust load corresponds to a decrease in the SLA of plant species. (a) (b) Figure 5: Analysis between SLA and dust load in winter (a) and monsoon (b) seasons Leaf length During winter, the leaf length was shortest in Azadirachta indica (6.11 ± 0.32 cm) at the industrial area), while the longest was recorded in Tectona grandis (41.44 ± 0.79 cm) at the 0 5 10 15 20 25 30 35 40 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r ed uc tio n in S LA Seasons/Study areas Artocarpus heterophyllus Azadirachta indica Citrus maxima Ficus benghalensis Ficus religiosa Nephelium Mangifera indica Neolamarckia cadamba Psidium guajava Syzygium cumini Saraca asoca Tectona grandis Figure 4: Percentage (%) reduction in SLA of different plant species in two seasons An inverse relationship was observed between dust load and specific leaf area (SLA) (Figure 5), indicating that an increase in dust load corresponds to a decrease in the SLA of plant species. (a) (b) Figure 5: Analysis between SLA and dust load in winter (a) and monsoon (b) seasons Leaf length During winter, the leaf length was shortest in Azadirachta indica (6.11 ± 0.32 cm) at the industrial area), while the longest was recorded in Tectona grandis (41.44 ± 0.79 cm) at the 0 5 10 15 20 25 30 35 40 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r ed uc tio n in S LA Seasons/Study areas Artocarpus heterophyllus Azadirachta indica Citrus maxima Ficus benghalensis Ficus religiosa Nephelium Mangifera indica Neolamarckia cadamba Psidium guajava Syzygium cumini Saraca asoca Tectona grandis Figure 4: Percentage (%) reduction in SLA of different plant species in two seasons Figure 5: Analysis between SLA and dust load in winter (a) and monsoon (b) seasons winter, while Nephelium litchi showed the highest reduction (28.46%) during the monsoon. Similarly, Mangifera indica at roadside (35.55% and 30.57%) and Neolamarckia cadamba at residential areas (37.08% and 6.98%) recorded maximum SLA reduction during both seasons. An inverse relationship was observed between dust load and specific leaf area (SLA) (Figure 5), indicating that an increase in dust load corresponds to a decrease in the SLA of plant species. Leaf length During winter, the leaf length was shortest in Azadirachta indica (6.11 ± 0.32 cm) at the industrial area), while the longest was recorded in Tectona grandis (41.44 ± 0.79 cm) at the roadside area (Table 52 Banko Janakari, Vol 35 No. 1 Shrestha et al. 6). During monsoon, Azadirachta indica had the shortest leaves (8.27 ± 0.19 cm) in the industrial area, while Tectona grandis had the longest (48.31 ± 1.17 cm) in the campus area. Overall, Tectona grandis consistently exhibited the largest leaf lengths across all studied areas, whereas Azadirachta indica had the smallest. The percentage of leaf length reduced mostly in industrial and roadside areas during winter compared to other areas and the monsoon season (Figure 6). In industrial areas, Mangifera indica exhibited maximum leaf length reduction (33.81%) during winter, but in monsoon Ficus benghalensis showed the greatest reduction (28.56%). At roadside locations, Ficus religiosa showed the maximum reduction in winter (5.21%), while Neolamarckia cadamba exhibited the highest reduction (29.79%) during monsoon. In residential areas, Saraca asoca showed maximum reduction during winter (5.43%), but in winter Psidium guajava showed the maximum reduction (38.51%). Leaf width During the winter season, the smallest leaf width was observed in Azadirachta indica (3.39 ± 0.02 cm), while the largest was in Tectona grandis (22.84 ± 0.93 Table 6: Leaf length (cm) of different plant species at different study areas during two seasons Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) roadside area (Table 6). During monsoon, Azadirachta indica had the shortest leaves (8.27 ± 0.19 cm) in the industrial area, while Tectona grandis had the longest (48.31 ± 1.17 cm) in the campus area. Overall, Tectona grandis consistently exhibited the largest leaf lengths across all studied areas, whereas Azadirachta indica had the smallest. Table 6: Leaf length (cm) of different plant species at different study areas during two seasons Plant species Industrial Roadside Residential Campus Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 12.08±0.36b 15.66±0.92bc 15.03±0.46bc 15.24±0.47bc - - 15.26±0.36b 15.75±0.81bc Azadirachta indica 6.11±0.32a 8.27±0.19a 8.26±0.78a 8.47±0.28a - - 8.36±0.79a 8.52±0.15a Citrus maxima 21.55±0.93d 11.88±0.25ab 22.08±0.95f 11.80±1.03ab - - 22.62±0.78e 12.66±0.35b Ficus benghalensis 12.36±0.28b 16.61±2.90bcd 16.35±0.79bc 16.70±0.69b - - 17.25±0.70bc 23.21±0.20d Ficus religiosa 13.57±0.17bc 12.23±1.53ab 14.61±0.18b 11.53±0.58ab - - 14.98±0.46b 13.68±0.42b Magnifera indica 14.14±0.51bc 19.49±2.31cd 21.29±0.21ef 17.00±2.00c 20.90±0.30a 17.30±3.26ab 21.38±0.21de 22.41±2.14d Neolamarckia cadamba 17.20±0.86c 21.00±1.54de 19.86±1.42def 16.69±1.41c 19.58±0.67 a 23.01±1.04b 19.60±0.69cde 23.75±0.49d Nephelium licthi 13.64±1.48bc 14.18±1.05b 18.31±1.90cde 15.42±1.29bc - - 18.78±2.09cd 16.92±1.33c Psidium guajava 15.78±0.64bc 15.64±1.60bc 20.93±1.87ef 13.81±0.43bc 21.66±2.47 a 11.46±0.68a 20.48±1.13cde 18.79±1.70c Syzygium cumini 12.24±1.21b 16.21±0.39bc 17.00±0.49bcd 13.44±2.24bc - - 17.35±0.57bc 17.29±0.70c Saraca asoca 23.31±3.44d 20.91±0.51d - - 25.18±2.37 a 19.90±0.97b 26.57±2.17f 22.23±0.61d Tectona grandis 40.41±1.31es 46.84±1.51e 41.44±0.79g 34.58±2.76d - - 42.52±0.93g 48.31±1.17e F-value 45.241 44.02 59.894 21.90 1.864 7.28 57.988 93.43 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36) The percentage of leaf length reduced mostly in industrial and roadside areas during winter compared to other areas and the monsoon season (Figure 6). In industrial areas, Mangifera indica exhibited maximum leaf length reduction (33.81%) during winter, but in monsoon Ficus benghalensis showed the greatest reduction (28.56%). At roadside locations, Ficus religiosa showed the maximum reduction in winter (5.21%), while Neolamarckia cadamba exhibited the highest reduction (29.79%) during monsoon. In residential areas, Saraca asoca showed maximum reduction during winter (5.43%), but in winter Psidium guajava showed the maximum reduction (38.51%). Figure 6: Percentage (%) reduction in leaf length of different plant species in two seasons Leaf width During the winter season, the smallest leaf width was observed in Azadirachta indica (3.39 ± 0.02), while the largest was in Tectona grandis (22.84 ± 0.93 cm) in the industrial area (Table 7). During monsoon, Azadirachta indica had the smallest leaf width (1.87 ± 0.08 cm) in the industrial area, while Tectona grandis had the largest (33.48 ± 1.25 cm) in the campus area. Overall, Tectona grandis exhibited the greatest leaf width across all study areas and seasons, whereas Azadirachta indica had the narrowest leaves. 0 5 10 15 20 25 30 35 40 45 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r ed uc tio n in le af le ng th Seasons/Study areas Artocarpus heterophyllus Azadirachta indica Citrus maxima Ficus religiosa Nephelium Mangifera indica Neolamarckia cadamba Psidium guajava Syzygium cumini Saraca asoca Tectona grandis Figure 6: Percentage (%) reduction in leaf length of different plant species in two seasons 53 Banko Janakari, Vol 35 No. 1Shrestha et al. cm) in the industrial area (Table 7). During monsoon, Azadirachta indica had the smallest leaf width (1.87 ± 0.08 cm) in the industrial area, while Tectona grandis had the largest (33.48 ± 1.25 cm) in the campus area. Overall, Tectona grandis exhibited the greatest leaf width across all study areas and seasons, whereas Azadirachta indica had the narrowest leaves. The percentage of leaf width reduction was higher in polluted area during monsoon season compared to the less polluted area (Figure 7). In industrial areas, Nephelium litchi during winter (13.30%) and Psidium guajava during monsoon (21.77%) season showed the highest reduction. At roadside, Syzygium cumini during winter (12.39%) and Neolamarckia cadamba during monsoon season (24.61%) showed the highest reduction. Similarly, in residential areas, Saraca asoca showed the maximum leaf width reduction in both seasons (5.30% in winter and 19.92% in monsoon). Chlorophyll-a Chlorophyll-a levels generally increased during the monsoon compared to the winter season, with industrial and less polluted areas showing significantly higher values than roadside and residential areas (Table 8). However, certain plant species like, Artocarpus heterophyllus, Ficus religiosa, Mangifera indica, Neolamarckia cadamba, Nephelium litchi, Psidium guajava, Syzygium cumini, and Saraca asoca exhibited higher chlorophyll-a levels during the winter season. In winter, chlorophyll-a ranged from 0.09 mg/g in Tectona grandis in industrial areas Table 7: Leaf width (cm) of different plant species at different study areas during two seasons Figure 7: Percentage (%) reduction in leaf width of different plant species in two seasons Table 7: Leaf width (cm) of different plant species at different study areas during two seasons Plant species Industrial Roadside Residential Campus Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 9.48±0.32de 7.79±0.65e 10.36±0.59ef 7.42±0.76d - - 10.69±0.36f 8.40±0.22e Azadirachta indica 3.39±0.02a 1.87±0.08a 3.36±0.02a 1.81±0.39a - - 3.56±0.52a 2.37±0.09a Citrus maxima 7.51±0.56c 4.90±0.04bc 8.15±0.51cd 5.03±0.38b - - 8.25±0.56de 5.59±0.34bc Ficus benghalensis 12.15±0.72f 10.47±0.80f 12.19±0.85fg 10.32±0.43e - - 12.93±0.88g 12.18±0.20f Ficus religiosa 10.85±0.46ef 7.26±0.38de 11.70±0.21fg 6.86±0.43cd - - 11.80±0.28fg 8.17±0.17e Magnifera indica 6.33±0.49cd 6.02±0.28cd 6.90±0.40bc 5.45±0.26bc 7.40±0.59b 6.24±0.78b 6.95±0.38cd 6.34±0.20cd Neolamarckia cadamba 11.17±0.80ef 12.76±1.14g 12.64±0.41g 10.30±0.65e 11.82±0.07c 12.60±0.08c 12.73±0.39g 13.65±0.43g Nephelium litchi 5.14±0.13ab 4.18±0.21b 5.59±0.40b 5.03±0.36b 5.94±0.18bc 5.21±0.33bc Psidium guajava 7.87±0.75cd 6.30±0.74cde 8.81±0.60cde 5.47±0.04bc 8.98±0.67b 5.35±0.10b 9.09±0.65e 8.01±0.52e Syzygium cumini 10.29±0.074ef 6.38±0.14cde 9.58±1.40de 6.47±0.31bcd - - 10.81±0.66f 6.99±0.77de Saraca asoca 4.74±0.42ab 4.16±0.22b - - 5.03±0.43a 3.53±0.34a 5.31±0.38b 4.44±0.23b Tectona grandis 22.84±0.93g 29.67±0.30h 22.30±0.54h 26.92±1.19f - - 24.10±0.41h 33.48±1.25h F-value 73.125 187.62 59.198 141.93 32.341 82.08 120.122 319.43 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12 to 36) The percentage of leaf width reduction was higher in polluted area during monsoon season compared to the less polluted area (Figure 7). In industrial areas, Nephelium litchi during winter (13.30%) and Psidium guajava during monsoon (21.77%) season showed the highest reduction. At roadside, Syzygium cumini during winter (12.39%) and Neolamarckia cadamba during monsoon season (24.61%) showed the highest reduction. Similarly, in residential areas, Saraca asoca showed the maximum leaf width reduction in both seasons (5.30% in winter and 19.92% in monsoon). Figure 7: Percentage (%) reduction in leaf width of different plant species in two seasons Chlorophyll-a 0 5 10 15 20 25 30 35 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r ed uc tio n in le af w id th Seasons/Study areas Artocarpus heterophyllus Azadirachta indica Ficus benghalensis Ficus religiosa Nephelium litchi Mangifera indica Neolamarckia cadamba Psidium guajava Syzygium cumini Saraca asoca Tectona grandis Table 7: Leaf width (cm) of different plant species at different study areas during two seasons Plant species Industrial Roadside Residential Campus Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 9.48±0.32de 7.79±0.65e 10.36±0.59ef 7.42±0.76d - - 10.69±0.36f 8.40±0.22e Azadirachta indica 3.39±0.02a 1.87±0.08a 3.36±0.02a 1.81±0.39a - - 3.56±0.52a 2.37±0.09a Citrus maxima 7.51±0.56c 4.90±0.04bc 8.15±0.51cd 5.03±0.38b - - 8.25±0.56de 5.59±0.34bc Ficus benghalensis 12.15±0.72f 10.47±0.80f 12.19±0.85fg 10.32±0.43e - - 12.93±0.88g 12.18±0.20f Ficus religiosa 10.85±0.46ef 7.26±0.38de 11.70±0.21fg 6.86±0.43cd - - 11.80±0.28fg 8.17±0.17e Magnifera indica 6.33±0.49cd 6.02±0.28cd 6.90±0.40bc 5.45±0.26bc 7.40±0.59b 6.24±0.78b 6.95±0.38cd 6.34±0.20cd Neolamarckia cadamba 11.17±0.80ef 12.76±1.14g 12.64±0.41g 10.30±0.65e 11.82±0.07c 12.60±0.08c 12.73±0.39g 13.65±0.43g Nephelium litchi 5.14±0.13ab 4.18±0.21b 5.59±0.40b 5.03±0.36b 5.94±0.18bc 5.21±0.33bc Psidium guajava 7.87±0.75cd 6.30±0.74cde 8.81±0.60cde 5.47±0.04bc 8.98±0.67b 5.35±0.10b 9.09±0.65e 8.01±0.52e Syzygium cumini 10.29±0.074ef 6.38±0.14cde 9.58±1.40de 6.47±0.31bcd - - 10.81±0.66f 6.99±0.77de Saraca asoca 4.74±0.42ab 4.16±0.22b - - 5.03±0.43a 3.53±0.34a 5.31±0.38b 4.44±0.23b Tectona grandis 22.84±0.93g 29.67±0.30h 22.30±0.54h 26.92±1.19f - - 24.10±0.41h 33.48±1.25h F-value 73.125 187.62 59.198 141.93 32.341 82.08 120.122 319.43 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12 to 36) The percentage of leaf width reduction was higher in polluted area during monsoon season compared to the less polluted area (Figure 7). In industrial areas, Nephelium litchi during winter (13.30%) and Psidium guajava during monsoon (21.77%) season showed the highest reduction. At roadside, Syzygium cumini during winter (12.39%) and Neolamarckia cadamba during monsoon season (24.61%) showed the highest reduction. Similarly, in residential areas, Saraca asoca showed the maximum leaf width reduction in both seasons (5.30% in winter and 19.92% in monsoon). Figure 7: Percentage (%) reduction in leaf width of different plant species in two seasons Chlorophyll-a 0 5 10 15 20 25 30 35 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r ed uc tio n in le af w id th Seasons/Study areas Artocarpus heterophyllus Azadirachta indica Ficus benghalensis Ficus religiosa Nephelium litchi Mangifera indica Neolamarckia cadamba Psidium guajava Syzygium cumini Saraca asoca Tectona grandis Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12 to 36) 54 Banko Janakari, Vol 35 No. 1 Shrestha et al. to 2.56 mg/g in Saraca asoca in less polluted areas. Similarly, during monsoon season, it ranged from 0.74 mg/g in Tectona grandis in industrial areas to 2.56 mg/g in Saraca asoca in less polluted areas. Reduction in Chlorophyll-a Mangifera indica from both industrial and residential areas, and Neolamarckia cadamba from the roadside, exhibited the lowest percentage of reduction in chlorophyll-a during the winter season (Figure 8). During monsoon season, plants species like Ficus benghalensis, Ficus religiosa, Magnifera indica, Neolamarckia cadamba and Syzygium cumini exhibited less percent of reduction in chlorophyll-a from different study areas. Chlorophyll-b Chlorophyll-b increased during the monsoon, with significant variations across study areas and plant species (p<0.05 in most cases). During the winter season, chlorophyll-b ranged from 0.04 mg/g in Tectona grandis in industrial areas to 0.52 mg/g in Saraca asoca in less polluted areas (Table 9). During monsoon, chlorophyll-b levels ranged from 0.66 mg/g in Nephelium litchi in industrial area to 1.05 mg/g in Psidium guajava in less polluted areas. Reduction in Chlorophyll-b The leaves of plants like Artocarpus heterophyllus, Citrus maxima, Neolamarckia cadamba and Ficus Table 8: Chlorophyll-a of different plant species at different study areas during two seasons Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12 to 36) Chlorophyll-a levels generally increased during the monsoon compared to the winter season, with industrial and less polluted areas showing significantly higher values than roadside and residential areas (Table 8). However, certain plant species like, Artocarpus heterophyllus, Ficus religiosa, Mangifera indica, Neolamarckia cadamba, Nephelium litchi, Psidium guajava, Syzygium cumini, and Saraca asoca exhibited higher chlorophyll-a levels during the winter season. In winter, chlorophyll-a ranged from 0.09 mg/g in Tectona grandis in industrial areas to 2.56 mg/g in Saraca asoca in less polluted areas. Similarly, during monsoon season, it ranged from 0.74 mg/g in Tectona grandis in industrial areas to 2.56 mg/g in Saraca asoca in less polluted areas. Table 8: Chlorophyll-a of different plant species at different study areas during two seasons Plant species Industrial Roadside Residential Campus Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 1.15±0.09d 0.95±0.12abc 0.68±0.15b 0.87±0.02bc - - 1.34±0.12bc 1.95±0.10d Azadirachta indica 0.61±0.06bc 0.78±0.04a 0.65±0.11b 1.54±0.26d - - 0.66±0.04a 1.64±0.36bcd Citrus maxima 0.45±0.03b 0.82±0.10ab 0.48±0.07b 1.00±0.08c - - 0.57±0.07a 1.69±0.32cd Ficus benghalensis 0.19±0.02a 1.16±0.08bcd 0.47±0.12b 0.99±0.07c - - 0.57±0.03a 1.45±0.30abcd Ficus religiosa 0.50±0.06b 0.94±0.07abc 1.25±0.07cd 0.95±0.04c - - 1.68±0.07bcd 1.00±0.05ab Mangifera indica 1.65±0.02e 1.51±0.00d 1.19±0.06c 0.93±0.17c 1.39±0.06b 1.21±0.18a 1.76±0.10cd 1.52±0.12abcd Neolamarckia cadamba 0.82±0.02c 1.41±0.07d 1.52±0.04d 0.97±0.09c 0.42±0.03a 1.59±0.35a 1.56±0.03bcd 1.78±0.31d Nephelium litchi 0.58±0.03bc 1.16±0.05bcd 1.04±0.02c 0.92±0.11c - - 1.60±0.04bcd 1.41±0.01abcd Psidium guajava 1.58±0.01e 1.35±0.19d 1.11±0.09c 0.50±0.04a 1.16±0.23b 0.92±0.08a 1.83±0.05d 1.73±0.10d Syzygium cumini 1.12±0.18d 0.94±0.13abc 1.12±0.18c 0.55±0.05ab - - 1.26±0.26b 1.05±0.11abc Saraca asoca 2.08±0.12f 1.26±0.04cd - - 0.64±0.06a 1.06±0.15+a 2.56±0.35e 1.63±0.00bcd Tectona grandis 0.09±0.01a 0.74±0.19a 0.11±0.01a 0.75±0.02abc - - 0.30±0.03a 0.94±0.02a F-value 56.24 5.69 17.52 5.53 12.55 1.74 21.47 2.65 p-value 0.00 0.00 0.00 0.00 0.00 0.23 0.00 0.02 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12 to 36) Reduction in Chlorophyll-a Mangifera indica from both industrial and residential areas, and Neolamarckia cadamba from the roadside, exhibited the lowest percentage of reduction in chlorophyll-a during the winter season (Figure 8). During monsoon season, plants species like Ficus benghalensis, Ficus religiosa, Magnifera indica, Neolamarckia cadamba and Syzygium cumini exhibited less percent of reduction in chlorophyll-a from different study areas. Figure 8: Percentage (%) reduction in Chlorophyll-a of plant species in two seasons Figure 8: Percentage (%) reduction in Chlorophyll-a of plant species in two seasons Chlorophyll-b Chlorophyll-b increased during the monsoon, with significant variations across study areas and plant species (p<0.05 in most cases). During the winter season, chlorophyll-b ranged from 0.04 mg/g in Tectona grandis in industrial areas to 0.52 mg/g in Saraca asoca in less polluted areas (Table 9). During monsoon, chlorophyll-b levels ranged from 0.66 mg/g in Nephelium litchi in industrial area to 1.05 mg/g in Psidium guajava in less polluted areas. 0 20 40 60 80 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential% R ed uc tio n in C hl -a Seasons/ Study areas Artocarpus hetrophyllus Azadirachta indica Citrus maxima Ficus religiosa Mangifera indica Neolamarckia cadamba Nephelium litchi Psidium gujava Syzygium cumini Saraca asoca Tectona grandis 55 Banko Janakari, Vol 35 No. 1Shrestha et al. Table 9: Chlorophyll-b of different plant species at different study areas during two seasons Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12-36) Table 9: Chlorophyll-b of different plant species at different study areas during two seasons Plant species Industrial Roadside Residential Less polluted Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 0.22±0.05cde 0.21±0.00ab 0.15±0.01ab 0.20±0.02abc - - 0.20±0.08a 0.23±0.02ab Azadirachta indica 0.11±0.06abc 0.20±0.05ab 0.11±0.00ab 0.14±0.06ab - - 0.16±0.04a 0.31±0.07a Citrus maxima 0.10±0.05abc 0.18±0.00a 0.16±0.03ab 0.23±0.05abcd - - 0.15±0.02a 1.07±0.49c Ficus benghalensis 0.11±0.02abc 0.34±0.06abcd 0.14±0.02ab 0.10±0.03a - - 0.16±0.01a 0.60±0.15abc Ficus religiosa 0.10±0.01abc 0.42±0.03cde 0.20±0.01bc 0.11±0.04a - - 0.56±0.21b 0.48±0.02ab Mangifera indica 0.32±0.01e 0.36±0.02bcde 0.30±0.04c 0.82±0.08e 0.30±0.05b 0.41±0.13a 0.40±0.03ab 0.83±0.06bc Neolamarckia cadamba 0.21±0.03bcd 0.44±0.01cde 0.31±0.02c 0.31±0.02bcd 0.13±0.00a 0.42±0.08a 0.35±0.01ab 0.58±0.12abc Nephelium litchi 0.15±0.01bcd 0.66±0.04f 0.18±0.04ab 0.37±0.11cd - - 0.24±0.01a 0.66±0.02abc Psidium guajava 0.26±0.02de 0.50±0.04def 0.22±0.00bc 0.13±0.00ab 0.19±0.00a 0.39±0.015a 0.37±0.01ab 1.05±0.04c Syzygium cumini 0.17±0.09bcd 0.30±0.02abc 0.17±0.09ab 0.17±0.00ab - - 0.26±0.05a 0.31±0.03ab Saraca asoca 0.40±0.02d 0.47±0.14cde - - 0.14±0.01a 0.68±0.25a 0.52±0.10b 0.80±0.08bc Tectona grandis 0.04±0.01a 0.53±0.02ef 0.06±0.02a 0.40±0.02d - - 0.18±0.01a 0.61±0.10abc F-value 8.92 7.19 4.17 14.87 9.20 0.84 3.44 2.84 p-value 0.00 0.00 0.00 0.00 0.00 0.50 0.00 0..01 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12-36) Reduction in Chlorophyll-b The leaves of plants like Artocarpus heterophyllus, Citrus maxima, Neolamarckia cadamba and Ficus benghalensis showed a minimum percentage of reduction in chlorophyll-b from polluted areas during winter season while (Figure 9), species like Nephelium litchi, Syzygium cumini and Mangifera indica showed less percentage of reduction in chlorophyll-b during monsoon season. 0 10 20 30 40 50 60 70 80 90 100 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r ed uc tio n in C hl -b Seasons/ Study areas Artocarpus hetrophyllus Azadirachta indica Citrus maxima Ficus benghalensis Ficus religiosa Mangifera indica Neolamarckia cadamba Nephelium litchi Psidium gujava Syzygium cumini Saraca asoca Tectona grandis Table 9: Chlorophyll-b of different plant species at different study areas during two seasons Plant species Industrial Roadside Residential Less polluted Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 0.22±0.05cde 0.21±0.00ab 0.15±0.01ab 0.20±0.02abc - - 0.20±0.08a 0.23±0.02ab Azadirachta indica 0.11±0.06abc 0.20±0.05ab 0.11±0.00ab 0.14±0.06ab - - 0.16±0.04a 0.31±0.07a Citrus maxima 0.10±0.05abc 0.18±0.00a 0.16±0.03ab 0.23±0.05abcd - - 0.15±0.02a 1.07±0.49c Ficus benghalensis 0.11±0.02abc 0.34±0.06abcd 0.14±0.02ab 0.10±0.03a - - 0.16±0.01a 0.60±0.15abc Ficus religiosa 0.10±0.01abc 0.42±0.03cde 0.20±0.01bc 0.11±0.04a - - 0.56±0.21b 0.48±0.02ab Mangifera indica 0.32±0.01e 0.36±0.02bcde 0.30±0.04c 0.82±0.08e 0.30±0.05b 0.41±0.13a 0.40±0.03ab 0.83±0.06bc Neolamarckia cadamba 0.21±0.03bcd 0.44±0.01cde 0.31±0.02c 0.31±0.02bcd 0.13±0.00a 0.42±0.08a 0.35±0.01ab 0.58±0.12abc Nephelium litchi 0.15±0.01bcd 0.66±0.04f 0.18±0.04ab 0.37±0.11cd - - 0.24±0.01a 0.66±0.02abc Psidium guajava 0.26±0.02de 0.50±0.04def 0.22±0.00bc 0.13±0.00ab 0.19±0.00a 0.39±0.015a 0.37±0.01ab 1.05±0.04c Syzygium cumini 0.17±0.09bcd 0.30±0.02abc 0.17±0.09ab 0.17±0.00ab - - 0.26±0.05a 0.31±0.03ab Saraca asoca 0.40±0.02d 0.47±0.14cde - - 0.14±0.01a 0.68±0.25a 0.52±0.10b 0.80±0.08bc Tectona grandis 0.04±0.01a 0.53±0.02ef 0.06±0.02a 0.40±0.02d - - 0.18±0.01a 0.61±0.10abc F-value 8.92 7.19 4.17 14.87 9.20 0.84 3.44 2.84 p-value 0.00 0.00 0.00 0.00 0.00 0.50 0.00 0..01 Note: Data are expressed as Mean± S.E and statistical analysis using one-way ANOVA for obtaining F and p values. Significance mean values among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12-36) Reduction in Chlorophyll-b The leaves of plants like Artocarpus heterophyllus, Citrus maxima, Neolamarckia cadamba and Ficus benghalensis showed a minimum percentage of reduction in chlorophyll-b from polluted areas during winter season while (Figure 9), species like Nephelium litchi, Syzygium cumini and Mangifera indica showed less percentage of reduction in chlorophyll-b during monsoon season. 0 10 20 30 40 50 60 70 80 90 100 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r ed uc tio n in C hl -b Seasons/ Study areas Artocarpus hetrophyllus Azadirachta indica Citrus maxima Ficus benghalensis Ficus religiosa Mangifera indica Neolamarckia cadamba Nephelium litchi Psidium gujava Syzygium cumini Saraca asoca Tectona grandis Figure 9: Percentage (%) reduction in Chlorophyll-b of plant species in two seasons benghalensis showed a minimum percentage of reduction in chlorophyll-b from polluted areas during winter season while (Figure 9), species like Nephelium litchi, Syzygium cumini and Mangifera indica showed less percentage of reduction in chlorophyll-b during monsoon season. Ratio of chlorophyll (a:b) The chlorophyll a:b ratio was higher during the winter season, particularly in less polluted areas, as observed in species like Artocarpus heterophyllus (Table 10). In contrast, industrial and roadside areas exhibited more variable levels of chlorophyll content. Notable species-specific trends were observed, such as Syzygium cumini showing elevated chlorophyll content in industrial and roadside during winter, while Tectona grandis consistently displayed low chlorophyll levels across all areas and seasons. Total chlorophyll Generally, plant species during monsoon seasons showed higher total chlorophyll levels, especially 56 Banko Janakari, Vol 35 No. 1 Shrestha et al. Table 10: Ratio of Chl (a:b) of different plant species in two seasons Note: Data are expressed as Mean± S.E and statistical analysis using one way ANOVA for obtaining F and p value. Significance mean value among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12 to 36) Figure 9: Percentage (%) reduction in Chlorophyll-b of plant species in two seasons Ratio of chlorophyll (a:b) The chlorophyll a:b ratio was higher during the winter season, particularly in less polluted areas, as observed in species like Artocarpus heterophyllus (Table 10). In contrast, industrial and roadside areas exhibited more variable levels of chlorophyll content. Notable species- specific trends were observed, such as Syzygium cumini showing elevated chlorophyll content in industrial and roadside during winter, while Tectona grandis consistently displayed low chlorophyll levels across all areas and seasons. Table 10: Ratio of Chl (a:b) of different plant species in two seasons Plant species Industrial Roadside Residential Campus area Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 6.06±1.78c 4.49±0.48bc 4.34±0.59a 4.36±0.39ab - - 11.57±0.66b 8.25±0.27c Azadirachta indica 5.35±0.28bc 4.86±1.92c 6.00±1.09a 18.07±4.26c - - 4.57±0.85a 5.26±0.22b Citrus maxima 4.58±0.05abc 4.41±0.48bc 3.24±0.89a 4.82±0.89ab - - 3.97±0.11a 4.45±0.31ab Ficus benghalensis 1.77±0.25a 3.70±0.75abc 15.72±1.78a 13.42±1.64ab - - 3.57±0.04a 2.49±0.39ab Ficus religiosa 4.99±0.81bc 2.22±0.04ab 5.99±0.19a 11.16±1.40abc - - 4.30±1.85a 2.07±0.01a Mangifera indica 5.13±0.06bc 4.17±0.27bc 4.00±0.35a 1.19±0.30ab 4.82±0.92ab 3.59±1.02a 4.42±0.67a 1.87±0.29a Neolamarckia cadamba 4.04±0.55abc 3.18±0.11abc 4.89±0.47a 2.72±0.64ab 3.19±0.21a 3.74±0.08a 4.48±0.24a 3.15±0.40ab Nephelium litchi 3.65±0.07abc 1.80±0.17a 6.67±1.98a 3.04±0.95ab - - 6.56±0.13b 2.12±0.09a Psidium guajava 6.17±1.10cd 2.63±0.12abc 4.96±0.54a 3.82±0.25ab 5.98±1.17b 2.36±0.23a 4.99±0.13a 1.63±0.04a Syzygium cumini 8.56±2.20d 3.09±0.14abc 8.56±2.20a 3.16±0.25ab - - 4.66±0.09a 3.43±0.09ab Saraca asoca 5.23±0.07bc 3.16±0.82abc - - 4.50±0.07ab 2.10±0.70a 5.01±0.64a 2.08±0.23a Tectona grandis 2.44±0.51ab 1.42±0.39a 2.86±1.52a 1.91±0.17a - - 1.69±0.07a 1.66±0.31a F-value 3.55 2.56 0.42 2.60 2.29 1.73 1.30 4.26 p-value 0.00 0.02 0.92 0.03 0.15 0.23 0.27 0.00 Note: Data are expressed as Mean± S.E and statistical analysis using one way ANOVA for obtaining F and p value. Significance mean value among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, n=12 to 36) Total chlorophyll Generally, plant species during monsoon seasons showed higher total chlorophyll levels, especially in less polluted areas. However, certain species like Saraca asoca, Mangifera indica and Psidium guajava showed higher amount of total chlorophyll during the winter season (Table 11). In contrast, Tectona grandis had the lowest levels, showing high sensitivity to pollution. During winter, total chlorophyll content ranged from 0.13 mg/g in Tectona grandis (industrial area) to 3.08±0.43 mg/g in Saraca asoca (less polluted area). In monsoon, the values range from 0.72 mg/g in Syzygium cumini (roadside area) to 2.78mg/g in Psidium guajava (less polluted area). Table 11: Total Chlorophyll of different plant species at different study areas during two seasons Note: Data are expressed as Mean± S.E and statistical analysis using one way ANOVA for obtaining F and p value. Significance mean value among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36)) Table 11: Total Chlorophyll of different plant species at different study areas during two seasons Plant species Industrial Roadside Residential Campus area Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 1.37±0.06f 1.16±0.12ab 1.37±0.05c 1.08±0.04b - - 1.54±0.16b 2.19±0.11ab Azadirachta indica 0.73±0.07cd 0.98±0.00a 0.73±0.07b 1.68±0.20c - - 0.82±0.07a 1.96±0.43ab Citrus maxima 0.56±0.03bc 1.00±0.10a 0.64±0.03b 1.23±0.14b - - 0.73±0.06a 2.77±0.81b Ficus benghalensis 0.30±0.04ab 1.49±0.03bcd 0.62±0.13b 1.10±0.04b - - 0.73±0.04a 2.06±0.43ab Ficus religiosa 0.60±0.06bc 1.37±0.11abc 1.47±0.09c 1.06±0.01b - - 2.24±0.27c 1.49±0.08a Mangifera indica 1.97±0.03g 1.88±0.015d 1.49±0.10c 1.76±0.08c 1.70±0.08b 1.63±0.18a 2.17±0.07b 2.36±0.06ab Neolamarckia cadamba 1.03±0.04de 1.85±0.08d 1.84±0.03d 1.35±0.10b 0.55±0.03a 2.01±0.43a 1.91±0.02bc 2.37±0.40ab Nephelium litchi 0.75±0.04cd 1.83±0.03d 1.22±0.04c 1.29±0.00b - - 1.85±0.05bc 2.07±0.02ab Psidium guajava 1.85±0.08g 1.86±0.24d 1.33±0.09c 0.63±0.05a 1.35±0.23b 1.31±0.08a 2.19±0.07c 2.78±0.14b Syzygium cumini 1.30±0.27ef 1.24±0.16ab 1.30±0.27c 0.72±0.05a - - 1.53±0.32b 1.36±0.15a Saraca asoca 2.48±0.14h 1.73±0.13cd - - 0.79±0.08a 1.74±0.22a 3.08±0.43d 2.44±0.09ab Tectona grandis 0.13±0.12a 1.27±0.18ab 0.17±0.00a 1.15±0.02b - - 0.48±0.04a 1.56±0.13a F-value 50.32 7.57 20.38 14.13 15.14 1.18 17.63 4.26 p-value 0.00 0.00 0.00 0.00 0.00 0.37 0.00 0.00 Note: Data are expressed as Mean± S.E and statistical analysis using one way ANOVA for obtaining F and p value. Significance mean value among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36)) Total chlorophyll content in the leaves Mangifera indica, Artocarpus heterophyllus, Azadirachta indica, Ficus benghalensis and Neolamarckia cadamba showed relatively lower reductions in polluted areas during the winter season (Figure 10). Conversely, Syzygium cumini, Ficus religiosa, Azadirachta indica, Neolamarckia cadamba exhibited less reduction in total chlorophyll content during the monsoon season. Figure 10: Percentage reduction in total chlorophyll content of different plant species in two seasons Discussion 0 10 20 30 40 50 60 70 80 90 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r eu ct io n in to ta l C hl Seasons/Study areas Artocarpus hetrophyllus Azadirachta indica Citrus maxima Ficus benghalensis Ficus religiosa Mangifera indica Neolamarckia cadamba Nephelium litchi Psidium gujava Syzygium cumini Saraca asoca Tectona grandis in less polluted areas. However, certain species like Saraca asoca, Mangifera indica and Psidium guajava showed higher amount of total chlorophyll during the winter season (Table 11). In contrast, Tectona grandis had the lowest levels, showing high sensitivity to pollution. During winter, total chlorophyll content ranged from 0.13 mg/g in Tectona grandis (industrial area) to 3.08±0.43 mg/g in Saraca asoca (less polluted area). In monsoon, the values range from 0.72 mg/g in Syzygium cumini (roadside area) to 2.78mg/g in Psidium guajava (less polluted area). Total chlorophyll content in the leaves Mangifera indica, Artocarpus heterophyllus, Azadirachta indica, Ficus benghalensis and Neolamarckia cadamba showed relatively lower reductions in polluted areas during the winter season (Figure 10). Conversely, Syzygium cumini, Ficus religiosa, Azadirachta indica, Neolamarckia cadamba exhibited less reduction in total chlorophyll content during the monsoon season. Discussion Dust load Dust load in industrial areas was comparatively higher during the winter seasons, primarily due to the presence of industries, brick kilns and factories. Elevated levels of particulate matter were found 57 Banko Janakari, Vol 35 No. 1Shrestha et al. Table 11: Total Chlorophyll of different plant species at different study areas during two seasons Plant species Industrial Roadside Residential Campus area Winter Monsoon Winter Monsoon Winter Monsoon Winter Monsoon Artocarpus heterophyllus 1.37±0.06f 1.16±0.12ab 1.37±0.05c 1.08±0.04b - - 1.54±0.16b 2.19±0.11ab Azadirachta indica 0.73±0.07cd 0.98±0.00a 0.73±0.07b 1.68±0.20c - - 0.82±0.07a 1.96±0.43ab Citrus maxima 0.56±0.03bc 1.00±0.10a 0.64±0.03b 1.23±0.14b - - 0.73±0.06a 2.77±0.81b Ficus benghalensis 0.30±0.04ab 1.49±0.03bcd 0.62±0.13b 1.10±0.04b - - 0.73±0.04a 2.06±0.43ab Ficus religiosa 0.60±0.06bc 1.37±0.11abc 1.47±0.09c 1.06±0.01b - - 2.24±0.27c 1.49±0.08a Mangifera indica 1.97±0.03g 1.88±0.015d 1.49±0.10c 1.76±0.08c 1.70±0.08b 1.63±0.18a 2.17±0.07b 2.36±0.06ab Neolamarckia cadamba 1.03±0.04de 1.85±0.08d 1.84±0.03d 1.35±0.10b 0.55±0.03a 2.01±0.43a 1.91±0.02bc 2.37±0.40ab Nephelium litchi 0.75±0.04cd 1.83±0.03d 1.22±0.04c 1.29±0.00b - - 1.85±0.05bc 2.07±0.02ab Psidium guajava 1.85±0.08g 1.86±0.24d 1.33±0.09c 0.63±0.05a 1.35±0.23b 1.31±0.08a 2.19±0.07c 2.78±0.14b Syzygium cumini 1.30±0.27ef 1.24±0.16ab 1.30±0.27c 0.72±0.05a - - 1.53±0.32b 1.36±0.15a Saraca asoca 2.48±0.14h 1.73±0.13cd - - 0.79±0.08a 1.74±0.22a 3.08±0.43d 2.44±0.09ab Tectona grandis 0.13±0.12a 1.27±0.18ab 0.17±0.00a 1.15±0.02b - - 0.48±0.04a 1.56±0.13a F-value 50.32 7.57 20.38 14.13 15.14 1.18 17.63 4.26 p-value 0.00 0.00 0.00 0.00 0.00 0.37 0.00 0.00 Note: Data are expressed as Mean± S.E and statistical analysis using one way ANOVA for obtaining F and p value. Significance mean value among different plant species are indicated by different letters. (Duncan multiple test, p≤0.05, (n=12 to 36)) Total chlorophyll content in the leaves Mangifera indica, Artocarpus heterophyllus, Azadirachta indica, Ficus benghalensis and Neolamarckia cadamba showed relatively lower reductions in polluted areas during the winter season (Figure 10). Conversely, Syzygium cumini, Ficus religiosa, Azadirachta indica, Neolamarckia cadamba exhibited less reduction in total chlorophyll content during the monsoon season. Figure 10: Percentage reduction in total chlorophyll content of different plant species in two seasons Discussion 0 10 20 30 40 50 60 70 80 90 Winter Monsoon Winter Monsoon Winter Monsoon Industrial Roadside Residential % r eu ct io n in to ta l C hl Seasons/Study areas Artocarpus hetrophyllus Azadirachta indica Citrus maxima Ficus benghalensis Ficus religiosa Mangifera indica Neolamarckia cadamba Nephelium litchi Psidium gujava Syzygium cumini Saraca asoca Tectona grandis Figure 10: Percentage reduction in total chlorophyll content of different plant species in two seasons in these areas compared to others. Dust load pollution is higher in winter than in the monsoon due to lack of precipitation, low wind speed and low temperature, which trap pollutants near the surface. Dry soil and increased human activities, vehicle movement and biomass burning further contribute to dust accumulation. In contrast, during the monsoon season, rainfall washes away dust particles, while strong wind disperses the pollutants and dense vegetation helps trap airborne particles thereby reducing atmospheric dust pollution (Linden et al., 2023). Similar findings were also reported by Chaturvedi et al. (2013) in industrial areas. Roadside and residential areas were reported as moderately polluted due to construction of roads and traffic congestion. The dust-holding capacity of the plants depends on various morphological traits and environmental conditions (Prusty et al., 2005). Plants growing near busy roads, and polluted areas like industries are highly affected by dust (Gostin, 2009; Leghari & Zaidi, 2013). This study found that high dust load was found in leaves with thick, rough, and hairy surfaces whereas low dust was accumulated on smoother and smaller leaf surface areas, consistent with the findings of Javanmard et al. (2019). In the present study, Tectona grandis from industrial areas - with rough surfaces, large surface area, and short petiole, accumulated more dust whereas species like Saraca asoca with smoother, flatter and smaller surface areas accumulated less dust. Dust deposition was more on Ficus benghalensis and Artocarpus heterophyllus compared to other species, likely due to their coriaceous and waxy leaf structures. Similar findings were also reported by Rai & Panda (2014). Dust accumulation can significantly obstruct stomatal pores, impeding the plant’s ability to perform gaseous exchange efficiently (Sawidis et al., 2012). This obstruction reduces CO2‚ uptake, leading to a decline in photosynthetic activity and energy production, which are vital for plant growth and metabolism. The findings of this study indicate that leaf physiological process appear to be significantly impacted by dust pollution than morphological traits. Physiological stress induced by dust pollution could lower chlorophyll content, decrease enzyme activity, and disrupt overall plant metabolism, as the dust layers block light penetration, which reduces photosynthetic activities (Swaidis et al., 2012). Reduction on leaf morphology Leaf area reduction was more pronounced in industrial areas during the winter season followed by roadside and residential areas. Similarly, leaf length and width were mostly reduced in polluted areas in monsoon seasons compared to less polluted controlled sites. These findings are consistent with those of Hamal & Chettri (2017) and Hamal (2023), who reported a reduction in leaf area and SLA in the polluted area as compared to that of a controlled less polluted area. Several studies have reported the effect of dust on plant morphological traits across different 58 Banko Janakari, Vol 35 No. 1 Shrestha et al. seasons in different plant species (Leghari & Zaidi, 2013; Rai & Panda, 2014; Lu et al., 2018). A reduction in SLA near polluted areas during winter season was also reported by Prasai (2021). Notably, Ficus religiosa and Nephelium litchi could be utilized for pollution control, as they exhibited a significant reduction in SLA indicating their strong dust trapping ability and adaptive leaf morphology (Singh & Kaushik, 2022). A reduction in leaf area, leaf length, and leaf width, in polluted areas than the non-polluted areas has been reported, which is consistent with the findings of the present study. The reduction in the leaf area, leaf length and leaf width might be due to the reduction of gaseous exchanges for photosynthesis and productivity of the leaf as the pollutants can block stomatal openings (Bhatti & Iqbal, 1988; Jahan & Iqbal, 1992; Leghari & Zaidi, 2013). Leaf area reduction is the result of air pollution that can block a plant’s ability to undergo photosynthesis effectively and reduce its resilience in coping with the strains posed by air pollutant stressors (Tiwari et al., 2006). Plants growing in polluted areas showed lower SLA (Yang et al., 2023). Plants species thriving in environments with limited amounts of nutrients, shortage of water and light, exhibited lower SLA values (Cornelissen et al., 1996). The inverse relationship between dust load and SLA near polluted sites found from this study corresponds with the findings of Hamal (2023). Furthermore, prolonged exposure to pollutants leads to reductions in leaf area, SLA, leaf length, and width (Meerabai et al., 2012) Chlorophyll content In this study, variation in chlorophyll-a and chlorophyll-b was observed across different plant species, likely driven by seasonal changes, dust accumulation, and leaf morphological traits. Seasonal changes primarily control chlorophyll variations, while dust load and leaf morphology act as modifying factors influencing their impact (Prajapati & Tripathi, 2008). In winter, dust accumulation due to minimal precipitation and low wind speed obstructed sunlight, thereby reducing photosynthesis and contributing to chlorophyll degradation. The monsoon rains helped to wash away dust, allowing for improved light absorption and a subsequent increase in chlorophyll content. Leaf traits also influenced the extent of dust accumulation, with plants having rough or hairy leaves tending to trap more dust, leading to greater chlorophyll loss. The chlorophyll-a to chlorophyll-b ratio was generally higher in winter, especially in less polluted areas. The study showed that chlorophyll-a was more affected than chlorophyll-b, which resembled the findings of Giri et al. (2013) and Talebzadeh & Valeo (2022). Chlorophyll-a and -b reduction was highest during the monsoon. Mangifera indica and Neolamarckia cadamba showed minimal reduction in chlorophyll-a during winter, while Ficus benghalensis, Ficus religiosa, Mangifera indica, Neolamarckia cadamba, and Syzygium cumini were less affected by dust in monsoon. Chlorophyll-b reduction was lowest in Artocarpus heterophyllus and Citrus maxima in winter, while Syzygium cumini and Mangifera indica exhibited better retention during the monsoon season. The photosynthetic pigments undergo several photochemical reactions like oxidation, reduction, and pheophytinisation to overcome stress due to which the chlorophyll content decreases in polluted areas (Tripathi & Gautam, 2007). The reduction of chlorophyll content in plants growing in polluted areas might also be due to the adverse effects of industrial and vehicular emissions on plant physiology (Dhyani et al., 2019). The reduction in chlorophyll contents might also be due to the uptake of heavy metals like Cu, Zn, and Pb through the leaf surfaces. Decreased chlorophyll (a:b) ratio with increasing pollution, also reported by Chettri et al. (1998), might be due to a decrease in chlorophyll-a and an increase in chlorophyll-b concentrations. This shift might occur because chlorophyll-b is synthesized from chlorophyll-a through the oxidation of the methyl group on ring II to an aldehyde (Bidwell, 1979). Conclusion Air pollutants significantly affect both the morphological and physiological characteristics of the tree leaves growing around industrial and roadside areas, particularly during the winter season, compared to those in residential and campus areas. Leaves with rough texture, large areas and complex structures, such as those of Tectona grandis showed higher dust accumulation than the leaves with smooth and smaller areas like those of Nephelium litchi and Psidium guajava. Plant leaf morphological characters were significantly reduced across the industrial, roadside and residential areas in comparison to that of campus areas during the winter than the monsoon seasons However, synthesis of chlorophyll-a was more significantly affected by dust pollution than chlorophyll-b, as evidenced by a higher chlorophyll a:b ratio in less polluted areas, particularly during winter indicating their resilience to seasonal variations and environmental stressors. Plant species like Artocarpus heterophyllus, Citrus maxima, Ficus 59 Banko Janakari, Vol 35 No. 1Shrestha et al. benghalensis, Ficus religiosa, Mangifera indica, Neolamarckia cadamba, Nephelium litchi and Psidium guajava showed minimal reductions in both morphological traits and chlorophyll content. These species, therefore, exhibit potential for use in urban greening and pollution mitigation strategies due to their relative tolerance to environmental pollutants. Acknowledgements We are thankful to the Research Directorate, Tribhuvan University for providing financial support under the National Priority Area Research program (Grant no. TU-NPAR-079/80-ERG-10). We also acknowledge the Biratnagar Metropolitan Office for granting permission to collect samples from the city area. Author’s contribution statement U. Shrestha: Sample collection, laboratory analysis, original draft writing, and formal analysis. S. Rijal, A. Shrestha, P. Adhikari: Sample collection and laboratory analysis. M. K. Chettri: Material collection, data curation and validation. B. D. Acharya, M. R. Paudel: Material collection and supervision. A. Devkota: Material collection, conceptualization, laboratory analysis, Writing- review and editing, and supervision Data availability The data used in the study are accessible upon request to the corresponding author. Declaration The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work in this paper. References Barnes, J. D., Balaguer, L., Manrique, E., Elvira, S., & Davison, A. W. (1992). A reappraisal of the use of DMSO for the extraction and determination of chlorophyll a and b in lichens and higher plants. Environmental and Experimental Botany, 32 (2), 85-100. https:// doi.org/10.1016/0098- 8472(92)90034-Y Bharti, S. K., Trivedi, A., & Kumar, N. (2017). Air pollution tolerance index of plants growing near an industrial site. Urban Climate, 24, 820-829. Bhatti, G. H., & Iqbal, M. Z. (1988). Investigations into the effect of automobile exhausts on the phenology, periodicity and productivity of some roadside trees. Acta Societatis Botanicorum Poloniae, 57 (3), 395-399. Bidwell, R. G. S. (1979). Plant Physiology. 2nd edition. Collier MacMillan Publishers, London. Chaturvedi, R. K., Prasad, S., Rana, S., Obaidullah, S. M., Pandey, V., & Singh, H. (2013). Effect of dust load on the leaf attributes of the tree species growing along the roadside. Environmental Monitoring Assessment, 185 (1), 383-391. Chettri, M. K., Cook, C. M., Vardaka, E., Sawidis, T., & Lanaras, T. (1998). The effect of Cu, Zn and Pb on the chlorophyll content of the lichens Cladonia convoluta and Cladonia rangiformisi. Environmental and Experimental Botany, 39, 1-10. Cornelissen, J. H. C., Diez, P. C., & Hunt, R. (1996). Seedling growth, allocation and leaf attributes in a wide range of woody plant species and types. Journal of Ecology, 84, 755–765. Dhyani, S., Devkota, A., Shrestha, S. D., & Jha, P. K. (2019). Effect of particulate matters on chlorophyll content in shrubby species growing along roadside of Kathmandu Valley. Botanica Orentalis- Journal of Plant Science, 13, 13-21. DOI. (2022). Industrial statistics fiscal year 2078/79 (2021/22). Department of Industry. Ministry of Industry, Commerce and Supplies. Planning, Monitoring and Industrial Statistics Section. Government of Nepal. Kathmandu, Nepal. Giri, S., Shrivastava, D.M., Deshmukh, K., & Dubey, P. (2013). Effect of Air pollution on chlorophyll content of leaves. Current Agriculture Research Journal, 1 (2), 93-98. Gostin, I. N. (2009). Air pollution on the leaf structure of some Fabaceae species. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 37 (2), 57-63. Hamal, J. P., & Chettri, M. K. (2017). Air pollution tolerance index of some selected gymnosperm species along the road side of Kathmandu Valley, Nepal. Ecoprint, 24, 13-19. Hamal, J. P. (2023). Assessment of road side trees in Kathmandu Valley or their air pollution tolerance index and heavy metal biomonitoring ability. [Unpublished doctoral dissertation]. Central 60 Banko Janakari, Vol 35 No. 1 Shrestha et al. Department of Botany. Institute of Science and Technology. Tribhuvan University. Nepal. Jahan, S., & Iqbal, M.Z. (1992). Morphological and anatomical studies of leaves of different plants affected by motor vehicles exhaust. Medical Journal of Islamic World Academy of Sciences, 5, 21–23. Javanmard, Z., Tabari, M. K., Bahrami, H., Hosseini, S. M., Sanavi, S. A. M. M., & Struve, D. (2019). Dust collection potential and air pollution tolerance indices in some young plant species in arid region of Iran. iForest - Biogeosciences and Forestry, 12 (6), 558-564. Jitin, R., & Jain, M. K. (2014). An investigation into the impact of particulate matter on vegetation along the National Highway: A review. Research Journal of Environmental Science, 8 (7), 356-372. Joshi, P. C., & Swami, A. (2007). Physiological responses of some tree species under roadside automobile pollution stress around city of Haridwar, India. Environmentalist, 27, 365-374. Kushwaha, A., Das, A., Dave, R., & Bhattacharya, B. K. (2024). A non-destructive estimation of chlorophyll-a and -b over different crops using airborne imaging spectroscopy observations. Advances in Space Research, 73 (2), 1290-1303. Leghari, S. K., & Zaidi, M. A. (2013). Effect of air pollution on the leaf morphology of common plant species of Quetta city, Pakistan. Pakistan Journal of Botany, 45, 447–454. Linden, J., Gustafsson, M., Uddling, J., Watne, A., & Pleijel, H. (2023). Air pollution removal through deposition on urban vegetation: The importance of vegetation characteristics. Urban Forestry and Urban Greening, 81, 127843. Liu, G., Wang, L., Jiang, L., Pan, X., Huang, Z., Dong, M., & Cornelissen, J. H. (2018). Specific leaf area predicts dryland litter decomposition via two mechanisms. Journal of Ecology, 106 (1), 218-229. Lu, S., Yang, X., Li, S., Chen, B., Jiang, Y., Wang, D., & Xu, L. (2018). Effects of plant leaf surface and different pollution levels on PM2.5 adsorption capacity. Urban Forestry and Urban Greening, 34, 64-70. Meerabai, G., Venkata Ramana, C., & Rasheed, M. (2012). Effect of air pollutants on leaves of pigeon pea, a pulse crop of Fabaceae growing in the vicinity of a silicon industry. World Rural Observations, 4 (2), 19-21. Nithamathi, C. P., & Indira, V. (2005). Impact of air pollution on Ceasalpinia sepiaria Linn. in Tuticorin City. Indian Journal of Environment and Ecoplanning, 10 (1), 449–452. Pandey, A. K., Pandey, M., Mohan, S., Tiwary, S. M., & Tripathi, B. D. (2015). Air pollution tolerance index and anticipated performance index of some plant species for development of urban forest. Urban Forestry and Urban Greenery, 14 (4), 866 – 871. Prajapati, S. K., & Tripathi, B. D. (2008). Anticipated performance index of some tree species considered for green belt development in and around an urban area: A case study of Varanasi city, India. Journal of Environmental Management, 88, 1343–1349. Prasai, P. (2021). Assessment of air pollution tolerance index and leaf structure of selected plant species around Udayapur cement factory, Nepal. [Unpublished M.Sc. dissertation]. Department of Botany, Amrit Campus, Tribhuvan University. Kathmandu, Nepal. Prusty, B. A. K., Mishra, P. C., & Azeez, P. A. (2005). Dust accumulation and leaf pigment content in vegetation near the national highway at Sambalpur, Orissa, India. Ecotoxicology Environmental Safety, 60 (2), 228–235. Rai, P. K., & Panda, L. L. S. (2014). Leaf dust deposition and its impact on biochemical aspect of some roadside plants of Aizawl, Mizoram, North East India. International Research Journal of Environment Science, 3 (11), 14-19 Sapkota, S., & Shrestha S. M. (2024). Assessment of air pollution tolerance index and anticipated performance index of roadside plants used for greenbelt development in Kathmandu valley, Nepal. Environmental Challenges, 14, 100818. Sawidis. T., Krystallidis. P., Veros. D., & Chettri. M. K. (2012). A study of air pollution with heavy metals in Athens city and Attica basin using evergreen trees as biological indicators. Biological Trace Element Research, 148 (3), 396-408. Sharma, A. P., Rai, P. K., & Tripathi, B. D. (2007). Magnetic biomonitoring of roadside tree leaves as a proxy of vehicular pollution. In L. L. Vyas (Ed.) Urban planning and environment: strategies and 61 Banko Janakari, Vol 35 No. 1Shrestha et al. challenges (pp. 326-331). Mc Millan advanced research series. Singh, B., & Kaushik, A. (2022). Suitability assessment of some tree species in traffic- area verges of Delhi, India for air pollution tolerancecum-performance for green urban planning. International Journal of Geography, Geology and Environment,4 (2), 122-134. Talebzadeh, F., & Valeo, C. (2022). Evaluating the effects of environmental stress on leaf chlorophyll content as anindex for tree health. In IOP Conference Series: Earth and Environmental Science, 1006 (1), p. 012007. https://doi. org/10.1088/1755-1315/1006/1/012007 Tiwari, S., Agrawal, M., & Marshall, F. M. (2006). Evaluation of ambient air pollution impact on carrot plants at a sub urban site using open top chambers. Environmental Monitoring and Assessment, 119 (1-3), 15-30. Tripathi, A. K., & Gautam, M. (2007). Biochemical parameters of plants as indicators of air pollution. Journal of Environmental Biology, 28, 127-132. Wang, Y., Chen, Y., Zhang, X., & Gong, W. (2021). Research on Measurement Method of Leaf Length and Width Based on Point Cloud. Agriculture, 11 (1), 63. https://doi. org/10.3390/agriculture11010063 Yang, Z., Zhang, X., Qu, Y., Gao, F., & Li, Y. (2023). Response of common garden plant leaf traits to air pollution in urban parks of Suzho city (China). Forests, 14 (11), 2253. https://doi.org/10.3390/ f1411225