The study, published in Air Quality, Atmosphere & Health, examined five tree species growing under roadside conditions in Nagpur, a rapidly developing city in Maharashtra where traffic, construction and urban expansion are contributing to deteriorating air quality. Roadside vegetation is exposed to a complex mixture of stressors. Exhaust gases can enter leaves through stomata, the microscopic pores that regulate gas exchange, while particles settle on leaf surfaces and may block light or interfere with stomatal function. Heat, limited soil moisture and repeated physical disturbance add to the burden. The researchers therefore assessed not only how much particulate matter leaves retained, but also how their internal physiology responded.

To estimate pollution tolerance, the team measured several biochemical and physiological traits used to calculate APTI. These included total chlorophyll, leaf-extract pH, relative water content and ascorbic acid concentration. Chlorophyll is essential for photosynthesis, and a decline in its concentration can indicate damage to the photosynthetic apparatus or reduced pigment production under stress. Relative water content reflects the hydration state of leaf tissue and its ability to maintain cellular function. Leaf pH can influence enzyme activity and the plant’s response to acidic pollutants, while ascorbic acid acts as an antioxidant that helps neutralize reactive oxygen species generated by pollution. Together, these variables provide a composite picture of how well a plant may withstand a contaminated environment.

The measurements revealed that roadside exposure altered the trees’ physiology. A two-way analysis of variance found significant effects of both site and species on total chlorophyll, leaf pH and relative water content, with probabilities below 0.001. The significant site-by-species interactions for chlorophyll and pH were especially important: they indicate that species did not respond identically to the same roadside conditions. Pollution and associated environmental stress could therefore not be represented by a universal effect across the urban forest. Some trees maintained more stable physiological characteristics, whereas others showed changes consistent with greater stress.

Overall, APTI values fell under roadside conditions, suggesting that pollution reduced physiological resilience across the trees examined. Yet the decline was not uniform. Pongamia pinnata recorded the highest polluted-site APTI, with a value of 8.0, while Lagerstroemia speciosa had the lowest value, 6.4. These numbers should not be interpreted as a direct measure of pollutant removal or as a universal ranking for every city. APTI is an index derived from plant traits, and its meaning depends on local climate, pollution composition, soil conditions and the particular species being tested. In Nagpur, however, the results identify Pongamia as the strongest physiological candidate among the trees studied.

The dust measurements told a different story. The researchers quantified DCC using a gravimetric method, weighing the particulate material retained on leaf surfaces after collection and processing. Ficus hispida captured the greatest amount, holding 1.26 milligrams of dust per square centimetre of leaf area. Leaf texture, hairiness, waxiness, surface roughness, orientation and canopy structure can all affect this capacity. Rough or complex surfaces create more opportunities for particles to adhere, while dense foliage can slow air movement and encourage deposition. The result is a form of passive filtration: leaves intercept some airborne material, although wind, rain and leaf movement can later redistribute or remove it.

The contrast between Pongamia pinnata and Ficus hispida exposed a central complication in designing pollution-fighting vegetation. A weak negative correlation was observed between APTI and DCC, with a correlation coefficient of −0.242 and a probability value of 0.090. In practical terms, trees that were more tolerant according to their internal biochemical traits did not necessarily retain more dust, and the relationship was not statistically strong. Survival and particle capture are distinct biological functions. A tree may protect its photosynthetic machinery effectively while presenting a relatively smooth leaf surface, whereas another may collect substantial dust but experience greater physiological stress as a result.

To combine these different qualities, the researchers used the Anticipated Performance Index. API extends the interpretation of APTI by incorporating additional characteristics relevant to urban planting and greenbelt performance. Such composite assessments can account for traits including growth form, canopy structure, evergreen or deciduous behavior and other practical features, rather than relying on a single biochemical score. In this analysis, Pongamia pinnata achieved the highest API score, followed by Ficus hispida. Both were categorized as good performers, while Tabebuia rosea recorded the lowest API performance. The ranking reinforces the idea that urban tree selection should be based on multiple functions rather than visual appeal or availability alone.

The findings do not suggest that planting trees can replace emission controls. Leaves can intercept particles, but they do not eliminate the sources of nitrogen oxides, sulfur dioxide, carbon monoxide or fine particulate matter, and vegetation may have complex effects on airflow in narrow streets. Dense canopies can sometimes reduce pollutant dispersion if poorly designed, while maintenance activities, resuspension of deposited dust and seasonal changes can alter the net benefit. The study also measured dust retained on leaves rather than directly demonstrating reductions in human exposure or ambient PM2.5 concentrations. A tree covered in particles is not automatically proof that nearby residents are breathing cleaner air.

Instead, the research offers city planners a more precise way to build layered green infrastructure. Species with high physiological tolerance could be positioned where pollution and heat are most intense, reducing the likelihood that a roadside planting will rapidly decline. Species with strong dust-capture characteristics could be incorporated into buffer zones, traffic dividers or vegetation barriers, provided they can remain healthy under local conditions. Mixing species may also reduce vulnerability to pests, drought and disease while combining complementary functions. The authors emphasize that such decisions should be adapted to pollution-affected areas, rather than copied unchanged from one city to another.

Nagpur’s roadside trees could also serve as living monitors of environmental stress. Changes in chlorophyll, leaf pH, water status and antioxidant chemistry can reveal that plants are being affected before visible injury becomes obvious. Repeated measurements across seasons and traffic environments could help distinguish the effects of exhaust emissions from those of drought, heat or poor soil. The authors acknowledge that the study’s data are available on reasonable request and that further work will be needed to connect leaf-level measurements with pollutant concentrations, canopy-scale removal and public-health outcomes.

The broader message is that a city’s greenbelt is a biological system, not a decorative strip of uniform foliage. Urban forests work through a combination of chemistry, physiology and physical structure, and their performance changes with species and location. In Nagpur, Pongamia pinnata emerged as the most promising all-round candidate according to the study’s combined index, while Ficus hispida distinguished itself as a highly effective dust collector. Using both kinds of evidence could help planners avoid a common mistake: choosing trees that look resilient or attractive without testing whether they can tolerate pollution, capture particles and continue growing. The most effective urban canopy may ultimately be one designed as carefully as an engineered air-filtration system.

Bhubaneswar, branded as a Smart City, presents a unique case study with its growing urban landscape. With rapid urbanization, residents face challenges related to environmental degradation, primarily driven by pollution and the increasing frequency of severe weather events. In this context, the choice of urban trees could influence not only the ecological balance but also the overall quality of life for the city’s inhabitants. By analyzing various species, the study aims to inform policymakers and urban planners about suitable tree species that thrive in such challenging environments.

The researchers adopted a comprehensive methodology to evaluate the resilience of various urban tree species against cyclone conditions and pollution in Bhubaneswar. They assessed a range of factors, including the species’ growth characteristics, pollution tolerance, and structural integrity. These parameters are crucial for trees that need to withstand high winds while also providing essential ecosystem services, such as oxygen production, carbon sequestration, and habitat provision for wildlife.

Moreover, the study took a multidisciplinary approach, integrating ecological, botanical, and urban planning perspectives. By doing so, it provides a holistic understanding of how urban trees can be a significant part of climate adaptability strategies. The findings underscore that while selecting tree species for urban landscapes, it is imperative to evaluate their compatibility with existing environmental conditions, ensuring not just survival but also growth and sustainability.

Numerous species were put to the test during this research, ranging from the traditional to the more exotic varieties known for their adaptability. The researchers particularly focused on trees that could provide shade and enhance the urban forest canopy, which is crucial for mitigating the urban heat island effect—a growing concern in many metropolitan areas. The study highlights that species such as the Ficus and Tamarind trees have shown remarkable resilience, making them ideal candidates for city landscaping under the threat of cyclones.

Pollution poses another significant threat to urban tree health. The researchers explored how certain species could effectively filter air pollutants, contributing to improved urban air quality. In a city like Bhubaneswar, where pollution levels often exceed safety standards, the role of trees as natural air purifiers is indispensable. It was found that certain species not only survive but thrive in polluted environments, offering a natural solution to air quality issues.

Interestingly, the relationship between urban trees and community well-being was also examined in this study. The presence of greenery in urban landscapes is linked to numerous mental and physical health benefits. Urban trees contribute to reduced stress levels, enhance concentration, and promote physical activity among residents. Thus, the researchers argue that investing in the right species for urban areas could lead to a healthier, happier population, while also equipping the city with the resilience needed to face environmental challenges.

A noteworthy aspect of this study is its implications for future urban planning and management strategies. By advocating for specific tree species based on thorough research, the authors provide actionable insights for city planners, encouraging them to take a proactive approach to urban forestry. The authors assert that understanding the local ecological dynamics and integrating this knowledge into planning processes is essential for sustainable urban growth.

The potential economic benefits of urban trees were also discussed extensively. Healthy urban forests can increase property values, attract tourism, and reduce infrastructure costs by lowering temperatures and controlling stormwater runoff. In this light, the study not only underscores the ecological importance of selecting appropriate tree species but also frames these trees as valuable assets from an economic standpoint.

As cities continue to evolve, they must also adapt to the changing climate landscape. This study offers a pathway towards developing resilient urban ecosystems that not only survive but thrive amid adversity. It shines a spotlight on the need for ongoing research into urban forestry, highlighting that with careful planning and species selection, cities can bolster their defenses against natural disasters while simultaneously enhancing residents’ quality of life.

Residents of Bhubaneswar, and similarly vulnerable urban areas, can take solace in the findings of this research, which serve as a beacon of hope in an era where climate change poses significant risks. The valuable insights provided by Behera and colleagues will stimulate discussions among policymakers, community leaders, and residents on how urban landscapes can be transformed into havens of ecological resilience.

Ultimately, this research extends beyond its immediate geographical context. The implications of emphasizing adaptive tree species in urban forestry resonate in cities around the globe, particularly in regions prone to extreme weather events and pollution. As the world grapples with the twin challenges of climate change and urbanization, studies like this underscore that nature-based solutions can offer a sustainable path forward, merging ecological integrity with human health and well-being.

In conclusion, evaluating urban tree species like those showcased in Bhubaneswar could be foundational in creating resilient and sustainable urban environments. By choosing the right species, cities can enrich their urban landscapes, bolster ecological health, and create more livable spaces for future generations. This study exemplifies the critical intersection between ecological research and urban planning, emphasizing the need for a collaborative approach in addressing the pressing challenges faced by modern cities.

Subject of Research: Evaluating urban tree species for cyclone-prone and polluted environments in urban contexts

Article Title: Evaluating urban tree species for cyclone-prone and polluted environments: evidence from Bhubaneswar Smart City, Odisha

Article References:
Behera, M.C., Behera, S.S. & Sahoo, U.K. Evaluating urban tree species for cyclone-prone and polluted environments: evidence from Bhubaneswar Smart City, Odisha.
Environ Monit Assess 198, 16 (2026). https://doi.org/10.1007/s10661-025-14867-w

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s10661-025-14867-w

Keywords: Urban Trees, Cyclones, Pollution, Bhubaneswar, Urban Planning, Environmental Resilience, Tree Species Evaluation, Urban Forestry, Climate Adaptation, Urban Ecosystems, Air Quality Improvement, Urban Greenery.