The research team, led by Richmond Oppong Darko of the Department of Planning at KNUST and colleagues from the university’s Centre for Settlement Studies, surveyed 356 residents across Ayeduase, Kotei, Bomso, and Deduako. These communities were purposefully selected because of their proximity to the university campus and their distinctive land-use patterns, making them ideal case studies for understanding how academic institutions act as engines of urban growth. The researchers combined closed-ended questionnaires with open-ended interviews, allowing them to capture both quantitative measures of environmental change and the nuanced, lived experiences of residents navigating that change.

The most striking finding concerns the sheer speed of physical transformation. Between 2003 and 2023, built-up infrastructure in the study area expanded from 65.8 percent to 87.05 percent of the land surface. That represents a dramatic conversion of what was once agricultural land, forest patches, and open space into residential blocks, student hostels, commercial premises, and access roads. The researchers attribute this acceleration primarily to the university’s growing population and the corresponding demand for student and staff housing, which spills well beyond the campus boundary into neighboring settlements.

This pattern is not unique to Kumasi. Across sub-Saharan Africa, universities have increasingly been recognized as anchors of urbanization, drawing migrants, stimulating local economies, and generating secondary development that municipal authorities often struggle to regulate. What makes the KNUST case particularly instructive is the clarity with which the causal chain can be traced: institutional growth drives population influx, population influx drives housing demand, and housing demand drives land conversion with measurable environmental consequences.

Among those consequences, residents identified noise pollution as the single most pressing concern, cited by 38.9 percent of respondents. Poor waste management followed closely at 33.1 percent. These are not abstract environmental indicators but daily realities that shape quality of life, public health, and community cohesion. Noise from student hostels, commercial activities, and increased vehicular traffic disrupts sleep patterns and contributes to stress, while inadequate waste collection infrastructure leads to open dumping, blocked drains, and heightened disease risk during the rainy season.

Beyond these two dominant complaints, the study documented a 21.25 percent loss of green infrastructure across the study period. Trees, vegetated buffers, and informal green spaces that once moderated local temperatures, absorbed stormwater, and supported urban biodiversity have been progressively cleared to make way for construction. This loss compounds other environmental pressures: increased carbon emissions from growing vehicular traffic, and poor drainage systems that, combined with wetland encroachment, have made flooding a recurring hazard in low-lying areas.

The researchers employed the Drivers-Pressures-State-Impact-Response (DPSIR) framework to structure their analysis, a widely used conceptual model in sustainability science that links causal drivers to environmental pressures, changes in environmental state, impacts on human wellbeing, and societal responses. This framework allowed the team to move beyond simple correlation and articulate the specific mechanisms through which university expansion translates into environmental degradation, from land-use change and population density to infrastructure overload and ecosystem service loss.

Based on their findings, the researchers propose a set of policy interventions aimed at reconciling continued academic growth with environmental sustainability. They recommend strict zoning and building regulations to manage urban expansion, the establishment of waste recycling programs developed in partnership with the university, the enforcement of noise control policies, and the creation of community-based biodiversity conservation initiatives that promote green infrastructure and mass transit systems. These recommendations reflect a growing recognition that universities cannot be treated as isolated institutional enclaves but must be integrated into broader urban planning frameworks.

The study’s implications extend well beyond Ghana. As higher education systems across Africa and the Global South continue to expand in response to rising demand, the environmental footprint of that expansion will only grow. Cities hosting major universities face a choice between reactive management, where environmental problems are addressed only after they become crises, and proactive planning, where institutional growth is anticipated and its spatial and ecological consequences are managed from the outset. The KNUST case suggests that without deliberate policy intervention, the latter path is far more likely to produce sustainable outcomes.

What emerges from this research is a portrait of university communities as complex socio-ecological systems where institutional ambition, market forces, and environmental limits intersect. The residents of Ayeduase, Kotei, Bomso, and Deduako are not passive recipients of change but active stakeholders whose perceptions and priorities must inform any credible sustainability strategy. As the researchers conclude, building a more sustainable environment in these communities will require coordinated action from researchers, policymakers, planners, and the university itself, working together to ensure that the benefits of academic expansion are not purchased at an unsustainable environmental cost.

Subject of Research: Environmental impacts of university-driven urbanization in communities near KNUST, Ghana

Article Title: Environmental costs of university expansion: perceptions and policy implications in selected communities, Ghana

Article References: Oppong Darko, R., Mensah, H., Asamoah, P. K. B., Boafo, H. K., Adazuru, P., & Simpeh, E. K. (2026). Environmental costs of university expansion: perceptions and policy implications in selected communities, Ghana. SN Social Sciences, 6(9), Article 388. https://doi.org/10.1007/s43545-026-01633-z

Image Credits: AI Generated

DOI: 10.1007/s43545-026-01633-z

Keywords: university expansion, urbanization, Ghana, KNUST, environmental degradation, noise pollution, waste management, land use change, DPSIR framework, urban planning, green infrastructure, sustainability

The analytical backbone of the study is the ISO 12913-1 standard, which defines soundscape as the acoustic environment as perceived or experienced and understood by a person, in context. That people-centered definition matters technically because it reframes the acoustic environment from a physical exposure metric, sound pressure level, into a perceptual construct shaped by interactions between sounds, human interpretation, and environmental setting. The researchers adapted this framework into an operational model with three components: soundscape characteristics, covering both the perception of individual sound sources such as birdsong, flowing water, or conversation and the holistic interpretation of the auditory environment; well-being-related outcomes, organized into four domains of environmental experience, human health, behavioral responses, and social well-being; and contextual factors, spanning environmental conditions, personal attributes, and temporal variables such as exposure duration and time of day.

The descriptive mapping of the literature revealed a strikingly uneven evidence base. Natural sounds were the most frequently examined category, appearing in 69.07 percent of the 194 studies, yet the research concentrated on a narrow set of sources, dominated by unspecified birdsong and mixed natural sounds. Human-sound research centered largely on music and speech. Human health was the dominant outcome domain, also examined in 69.07 percent of studies, followed by environmental experience at 32.99 percent, while behavioral responses and social well-being were comparatively neglected. Equally notable is how rarely domains were examined together: only 16.49 percent of studies covered two outcome domains, and none covered three or more. Roughly one third of the studies, 36.08 percent, examined no testable contextual factor at all. The most frequently studied pathway, natural sounds in relation to human health, appeared in 101 cumulative instances, whereas associations between overall soundscape perception and social well-being or behavioral responses appeared in only four and three instances respectively, too few for robust cross-study synthesis.

Where the evidence permitted quantitative pooling, the meta-analysis delivered its headline findings. Natural sounds showed moderate positive effects across environmental experience, human health, and social well-being, with Hedges’ g ranging from 0.53 to 0.59, and the largest effect on human health at g = 0.59 with a 95 percent confidence interval of 0.42 to 0.76. Human sounds showed a more targeted profile: no significant effects on environmental experience or human health in the main-effects model, but moderate positive effects on behavioral responses at g = 0.60, 95 percent CI 0.24 to 0.97, and small positive effects on social well-being at g = 0.38, 95 percent CI 0.08 to 0.68. In plain terms, birdsong and flowing water reliably make people feel better, while the sounds of other people, conversation, music, and play, more selectively shape how people behave in and feel about public space.

Drilling into the health domain revealed a differentiated pattern with direct relevance to viral claims about nature sounds. Natural sounds showed positive effects across all health subtypes, but mental health stood out as the strongest at g = 0.83, 95 percent CI 0.64 to 1.02, significantly stronger than physical health, with a difference of 0.53, and cognitive health, with a difference of 0.35. Human sounds showed a significant effect only for mental health, at g = 0.46. For environmental experience, both sound types improved overall environmental appraisal, natural sounds at g = 0.66 and human sounds at g = 0.54, whereas effects on specific sensory sub-dimensions, visual, thermal, and olfactory experience, did not differ significantly from zero. The authors suggest that soundscape effects are typically expressed at the level of integrated environmental appraisal, where auditory information interacts with visual, thermal, olfactory, spatial, and social cues, though they caution that weaker effects for specific sensory variables may partly reflect how rarely and inconsistently those experiences are measured.

Source-specific analyses added crucial nuance, undercutting any simple prescription that biological sounds are always good. Mixed birdsong showed particularly large effects on environmental experience at g = 1.27, 95 percent CI 0.69 to 1.85, and on social well-being at g = 0.57. Music showed the most consistent positive effects among human sounds, especially for environmental experience at g = 1.20, 95 percent CI 0.81 to 1.58, and the interaction model even revealed a significant positive effect of music on thermal comfort at g = 0.57 that was not apparent in the main-effects model. But dog barking, a biological sound by category, showed a strongly negative effect on environmental experience at g = -1.21, 95 percent CI -1.78 to -0.64. The meaning a sound carries, its intensity, source identity, and compatibility with the setting, matters as much as its broad category. Water sounds may be restorative when perceived as natural and clean, but less effective when artificial, excessively loud, or visually disconnected from the environment.

Contextual moderation proved to be the study’s most technically consequential contribution. Environmental setting type moderated soundscape-well-being relationships in opposite directions for the two sound types: natural sounds were effective for environmental experience in outdoor settings at g = 0.57 but not in no-visual settings, whereas human sounds showed the reverse pattern, significant in no-visual settings at g = 0.59 but not outdoors. Yet the interaction model revealed that within no-visual settings, where the auditory pathway is isolated from competing cues, natural sounds produced their largest effects on overall environmental experience at g = 0.96 and mental health at g = 1.17, an estimate of what sound alone can achieve. Control group type mattered as well: effect sizes were generally larger when soundscapes were compared with noise exposure than with silence, and human sounds showed significant positive effects primarily as alternatives to noise. Relative to noise, both sound types improved environmental experience and mental health, natural sounds reaching g = 1.18 for mental health. The authors interpret this carefully: part of the observed benefit of human sound may reflect relief from an adverse acoustic baseline rather than an intrinsic benefit of the sound itself.

Exposure duration and geography added further layers of conditionality. Effects did not increase monotonically with exposure. For human health, the largest effect sizes for both natural sounds, g = 0.73, and human sounds, g = 0.53, occurred at just one to five minutes of exposure. Short exposure to natural sounds affected mental and physical health, effects on mental health persisted beyond five to ten minutes, and a significant effect on cognitive health emerged only after more than ten minutes, at g = 1.00. Geographical context significantly moderated relationships, particularly for natural sounds, with larger effects on environmental experience in Europe, g = 0.78, than in Asia, g = 0.46, while significant health effects for both sound types were observed only in studies conducted in Asia. The authors stress that these four moderators are proxies for context rather than measurements of it, recording where a study was conducted or how it was designed, not the perceived meaning, appropriateness, or social fit that the patterns implicate. That context-dependence is visible at all through instruments this coarse suggests the true dependence of human-sound effects on listening conditions is likely stronger than the estimates indicate.

The limitations are candidly acknowledged. Primary studies varied substantially in design, stimuli, control conditions, outcome measures, and exposure duration, and the multilevel model, which nests effect sizes within studies using the metafor package in R, partitions heterogeneity into between-study and within-study components but does not resolve these conceptual differences. Sparse reporting of demographic, cultural, and temporal detail forced coarse contextual coding, and given the multiplicity of models and post-hoc pairwise comparisons, moderator findings remain exploratory even with Benjamini-Hochberg false-discovery-rate adjustment. Blinding of participants or experimenters is rarely feasible in auditory interventions. The review was confined to English-language, peer-reviewed, quantitative studies, excluding qualitative methods, conference papers, and scholarship strands such as acoustic ecology and technical acoustic modeling, so the evidence base represents a specific subset of the field. Publication bias testing detected potential small-study or time-lag effects in three models, with no significant evidence in the remaining models.

The planning implications are nonetheless concrete. For health outcomes, the consistent positive effects of natural sounds support protecting and enhancing restorative acoustic resources, birdsong, water, and wind-induced vegetation sounds, alongside continued reduction of intrusive mechanical noise. Because such sounds depend on the ecological and spatial conditions that generate them, this implies habitat management, ecologically appropriate water features, vegetation structures, and spatial buffers against traffic-noise intrusion, making the identification and protection of existing high-quality soundscapes as important as creating new ones. For social well-being, certain human sounds may support social presence, perceived safety, and place attachment in settings designed for interaction, but should not be added indiscriminately; in quiet or restorative settings the same sounds may be unnecessary or intrusive. Interventions, the authors argue, should be evaluated not only by decibel reduction but also by perceived appropriateness, pleasantness, restoration, behavioral use, and social meaning. The dual strategy is clear: keep reducing harmful noise exposure while explicitly recognizing, protecting, and designing for the positive contributions of sound. The city of the future, on this evidence, will not be silent. It will be composed.

Subject of Research: Urban Sustainability

Article Title: Beyond noise and silence: urban soundscapes and their contribution to human well-being—a systematic review and meta-analysis

Article References: Guo, X., Schmidt, S., Chen, Z., Yang, L., Liu, J., & Albert, C. (2026). Beyond noise and silence: urban soundscapes and their contribution to human well-being—a systematic review and meta-analysis. npj Urban Sustainability, 6(1), Article 130. https://doi.org/10.1038/s42949-026-00482-2

Image Credits: AI Generated

DOI: 10.1038/s42949-026-00482-2

Keywords: soundscapes, urban planning, well-being, noise pollution, meta-analysis, environmental psychology, public health, birds, Beyond, noise, silence, urban

The scale of the land transformation emerges clearly from the satellite record. Between 2005 and 2024, agricultural land in and around Dehradun declined by 34 percent, forest cover fell by 14 percent, and grassland buffers diminished by 39 percent. Each of these losses matters for reasons that go beyond scenery. Farmland conversion removes the peri-urban soils that once absorbed rainfall and recharged aquifers; forest loss erodes slope stability and biodiversity habitat in a seismically and hydrologically sensitive Himalayan setting; and disappearing grasslands strip away the transitional zones that filter runoff and moderate local climate. The study attributes much of this conversion to sprawling, low-density development rather than compact growth, a pattern long associated with inefficient infrastructure provision and greater per-capita environmental burdens. In Dehradun’s case, the sprawl proceeded with little of the regulatory coordination that planners might have hoped the city’s master plan and smart city proposals would impose.

The most direct human consequence documented by the team is the deterioration of groundwater, the resource on which much of the city depends. Total dissolved solids in the city’s groundwater increased by more than 70 percent over the study period. Water hardness rose from 142.5 milligrams per liter to 197.4 milligrams per liter, climbing toward and past thresholds that consumers and regulators find concerning. Nitrate concentrations were found to frequently exceed permissible limits, a classic signature of sewage infiltration and fertilizer leaching, and the researchers recorded widespread microbial contamination across monitored wells. For a city perched above porous Himalayan foothill aquifers, these numbers describe more than a technical problem. They indicate that the same ground on which houses and roads now stand is transmitting waste-derived contaminants directly into the drinking water supply, with potential consequences for public health that the indicators only begin to capture.

Air quality tells a parallel story of growth outpacing environmental capacity. Across Dehradun’s major urban corridors, PM10 concentrations increased by 45 to 60 percent and PM2.5 concentrations by 40 to 80 percent over the study period. Particulate matter at these sizes penetrates deep into the lungs and enters the bloodstream, and epidemiological research has linked long-term exposure to cardiovascular and respiratory disease. In a valley city where topography can trap pollutants during temperature inversions, rising particulate loads compound an already vulnerable atmospheric setting. The study’s statistical modeling makes the connection explicit: built-up expansion correlated strongly with PM2.5 levels, with a correlation coefficient of 0.84, among the strongest associations reported in the analysis. In other words, the spatial pattern of new construction does not merely coincide with dirtier air; the two move together closely enough that land-use policy is, in effect, air-quality policy.

Water and air are not the only media under stress. Noise monitoring revealed that levels exceeded regulatory standards at more than 65 percent of the locations surveyed, a burden concentrated along the transport corridors where traffic, construction, and commercial activity converge. Chronic noise exposure is associated with sleep disturbance, elevated stress hormones, and cardiovascular risk, yet it is among the least regulated dimensions of urban environmental quality in fast-growing Indian cities. Meanwhile, the city’s material flows have swelled beyond its capacity to process them. Municipal solid waste generation reached 280 tonnes per day, but processing efficiency stands at only 70 percent, meaning roughly a third of the daily waste stream is unaccounted for in terms of treatment, with predictable consequences for land, water, and air. Sewage treatment capacity, likewise, remains below the volume of wastewater the city actually generates, leaving untreated effluent to find its way into groundwater and surface channels.

The statistical backbone of the study gives these observations their force. By correlating built-up expansion against a suite of environmental indicators, the researchers demonstrated that degradation is not randomly distributed but systematically tied to the geography and pace of development. Groundwater TDS correlated with built-up growth at 0.82, and nitrate concentration at 0.77, alongside the 0.84 coefficient for PM2.5. In environmental research, correlation coefficients of this magnitude across independent indicators are notable, because they suggest a common driver rather than a collection of unrelated local problems. The authors frame this as evidence that unregulated spatial growth functions as an integrated stressor: the same expansion that paves over recharge zones also concentrates traffic, generates waste, and outpaces the sewerage network. Addressing any single indicator in isolation, the analysis implies, will fail so long as the underlying land-use trajectory remains unchecked.

Set against the Sustainable Development Goals, the picture darkens further. SDG 11 calls for cities that are inclusive, safe, resilient, and sustainable, with specific targets covering air quality, waste management, water and sanitation, and access to green public space. The study finds substantial deviations from these targets in Dehradun on nearly every dimension it measured: particulate pollution rising rather than falling, waste processing short of full coverage, sewage treatment lagging behind generation, water quality deteriorating, and the green and agricultural land base contracting. The researchers’ assessment of urban infrastructure performance, drawing on census data, municipal datasets, and environmental monitoring records, indicates that infrastructure augmentation has simply not kept pace with the physical growth of the city. This is a pattern familiar across Himalayan hill towns, where steep terrain, limited flat land, and ecological fragility magnify the costs of every unplanned extension of the urban edge.

The methodological approach itself carries lessons for other cities in the region. By combining freely available Landsat and Sentinel imagery with supervised classification and post-classification change detection, the team produced a two-decade change record without requiring expensive bespoke data collection. Anchoring the satellite analysis in census data, municipal records, and environmental monitoring allowed the researchers to move from mapping to causally suggestive statistics, connecting the where of urban growth to the what of environmental harm. For city governments with limited analytical budgets, this kind of indicator-based geospatial framework offers a replicable template: it can flag which corridors are degrading fastest, which aquifers are failing, and which SDG targets are most off-track, providing an evidence base for prioritizing interventions before conditions become irreversible.

The authors’ prescription is correspondingly integrated rather than piecemeal. They call for strengthened land-use regulation, ecological conservation of the remaining forest and grassland buffers, augmentation of water, sewage, and waste infrastructure, and climate-resilient urban planning to steer Dehradun back toward sustainable development. None of these measures is novel in itself; what the study adds is quantitative proof that in Dehradun they are interdependent. Every year of continued sprawl simultaneously worsens the air residents breathe, the water they drink, and the noise they endure, while eroding the natural systems that could buffer the city against floods, landslides, and a warming climate. As Himalayan foothill cities across India and neighboring countries absorb some of the world’s fastest urban growth, Dehradun’s two-decade satellite record stands as a clear-eyed account of what unmanaged expansion costs, and a data-driven argument for why the next two decades must be different.

Subject of Research: Urban sprawl and its environmental impacts in Dehradun, India, assessed through geospatial and environmental indicator analysis against SDG 11

Article Title: Assessing urban sprawl, environmental vulnerability, and SDG 11 alignment using geospatial and environmental indicator-based analysis in Dehradun, India

Article References: Bharmoria, R., Nainwal, R., Chaturvedi, P., & Belwal, H. (2026). Assessing urban sprawl, environmental vulnerability, and SDG 11 alignment using geospatial and environmental indicator-based analysis in Dehradun, India. SN Social Sciences, 6(10), Article 541. https://doi.org/10.1007/s43545-026-01827-5

Image Credits: AI Generated

DOI: 10.1007/s43545-026-01827-5

Keywords: urban sprawl, Dehradun, land use land cover change, remote sensing, groundwater quality, air pollution, noise pollution, SDG 11, sustainable cities, Himalayan foothills, environmental indicators, urban planning

The research team, led by Kawthar Jaber Fadlallah and colleagues at the Center for Collaborative Research Initiatives in Public Health and Saint-Joseph University of Beirut, used an explanatory sequential mixed-methods design, a two-stage approach that pairs breadth with depth. First, they surveyed 228 intensive care nurses across Lebanon between March and June 2025, asking them to rate noise sources and the perceived impact of noise across four domains: subjective perception, emotion, physiology, and performance. Then, between September and October 2025, they conducted semi-structured interviews with 20 nurses purposively selected from the survey respondents, analyzing the transcripts thematically to explain what the numbers showed.

The survey results paint a picture of an environment saturated with machinery. Most noise sources were rated as moderate, but monitor alarms and ventilators stood out as the leading high-level source, cited by half of the nurses. Alarm fatigue, the desensitization that develops when clinicians hear hundreds of alerts per shift, is a well-documented safety concern in critical care, and this study confirms that in Lebanese ICUs the alarm-ventilator duo dominates the soundscape that nurses cannot escape.

Perhaps the most technically interesting finding lies in the impact scores. Across all four domains, the mean scores fell below the midpoint of the scale: subjective perception at 11.0 plus or minus 3.4, emotion at 13.8 plus or minus 4.4, physiology at 14.2 plus or minus 4.3, and performance at 10.6 plus or minus 4.2. On the surface, that might suggest noise is not a severe problem. But the qualitative interviews revealed a subtler and more troubling interpretation. Nurses described getting used to the noise while simultaneously reporting impaired concentration, having to repeat tasks, tinnitus, and headaches that persisted after their shifts ended. Their adaptation, the authors conclude, reflected endurance rather than relief.

This distinction matters scientifically. Habituation to noise is often assumed to be protective, a form of resilience in which the nervous system learns to filter out irrelevant stimuli. But psychophysiological research has long suggested that even when people report no longer noticing a noise, their bodies may still be responding, with elevated stress hormones, disturbed sleep, and cardiovascular strain. The Lebanese nurses’ accounts of tinnitus and post-shift headaches are consistent with that literature: subjective adaptation can coexist with objective wear.

Geography added another layer to the story. In bivariate analysis, the perceived impact of noise varied significantly by region across all four domains, with p-values at or below 0.017. Impact was highest in the Beqaa region and lowest in North Lebanon. The authors link this pattern to the strained context in which Lebanese nurses work, a health system under chronic economic and institutional pressure in a low- and middle-income country setting, where resources for noise mitigation, alarm management technology, and staff support may be scarce or unevenly distributed.

Experience also shaped perception. The perceived impact in the subjective perception domain increased with longer hospital tenure (r = 0.17, p = 0.009) and longer ICU experience (r = 0.13, p = 0.046). That correlation is counterintuitive at first glance: surely veterans should be least bothered by noise. But it aligns with the endurance interpretation. The longer nurses work in the unit, the more they become aware of what the noise is doing to them, even as they learn to function through it. Accumulated exposure appears to sharpen awareness of the toll rather than dull it.

Burnout emerged as a central thread. The mean burnout score of 3.5 plus or minus 1.2 fell exactly at the lower boundary of the band indicating the presence of burnout, meaning a substantial share of the surveyed nurses were already experiencing the emotional exhaustion and reduced professional efficacy that define the syndrome. The interviews connected this to the noise environment indirectly but persuasively: nurses coping with constant auditory stress, cognitive disruption, and physical symptoms described informal, individually driven coping strategies, while institutional responses were inconsistent at best.

That last point may be the study’s most actionable insight. Where hospitals failed to provide systematic noise management, nurses managed noise on their own, improvising solutions that the researchers linked to the broader LMIC context of systemic strain. The authors argue that this pattern supports system-level mitigation rather than reliance on individual habituation. In practice, that could mean alarm customization and tiered alerting to reduce false alarms, sound-absorbing architectural materials, designated quiet periods, staff education on noise behavior, and acoustic monitoring integrated into unit quality metrics, all interventions that have shown promise in critical care research worldwide.

The study has limits worth noting. It measured perceptions rather than objective sound levels, and its cross-sectional design captures a single moment in time, so causal claims about noise causing burnout cannot be firmly drawn. The sample, while geographically broad within Lebanon, reflects one national context during a period of exceptional strain. Still, by combining quantitative scores with the lived accounts of 20 nurses, the research captures something numbers alone cannot: the quiet resignation of professionals who have learned to keep working through a hazard their institutions have not yet learned to control. For intensive care units everywhere, and especially in resource-constrained settings, the message is that adaptation is not a solution. It is a symptom.

Subject of Research: Nurses' perceptions of noise pollution and its health effects in intensive care units in Lebanon

Article Title: Noise pollution in the intensive care unit: a mixed − methods exploration of Lebanese nurses’ perceptions

Article References: Jaber Fadlallah, K., Bou Dib, J., El Khoury, J. M., El Masri, R., Sahily, R., & Stephan Yeretzian, J. (2026). Noise pollution in the intensive care unit: a mixed − methods exploration of Lebanese nurses’ perceptions. BMC Public Health. https://doi.org/10.1186/s12889-026-29813-9

Image Credits: AI Generated

DOI: 10.1186/s12889-026-29813-9

Keywords: noise pollution, intensive care unit, nurses, burnout, occupational health, alarm fatigue, Lebanon, mixed methods, LMIC, tinnitus, ventilators, monitor alarms

Temporomandibular disorders, commonly abbreviated as TMD, encompass a range of painful conditions affecting the jaw joint and the muscles that control chewing. Sufferers often experience jaw pain, clicking or popping sounds when opening the mouth, difficulty chewing, headaches, and in severe cases, locking of the jaw. The condition is notoriously multifactorial, with stress, sleep disturbances, parafunctional habits such as clenching, and occlusal abnormalities all implicated. What has remained largely unexplored until now is whether the ambient acoustic environment itself, a chronic low-grade stressor that millions of city dwellers endure around the clock, might tip susceptible individuals toward these disorders.

The research team, led by Abdullah Hasan A. Alshehri and colleagues, enrolled 300 adults in New Delhi, India, splitting them evenly between residents of high-traffic and low-traffic areas. Rather than relying on subjective impressions of noise, the investigators measured individual-level exposure objectively, recording the equivalent continuous sound level over a full 24-hour period, denoted LAeq,24h. Each participant was then evaluated with validated clinical instruments. Temporomandibular disorders were diagnosed using the Diagnostic Criteria for Temporomandibular Disorders, the internationally recognized Axis I framework. Bruxism, the involuntary grinding or clenching of teeth, was assessed with established screening tools, as was malocclusion. The researchers also administered the Perceived Stress Scale, known as the PSS-10, and the Pittsburgh Sleep Quality Index to capture psychological and sleep-related factors that could confound the relationship.

The differences between the two groups were striking. Among residents of high-traffic areas, 61.3 percent met diagnostic criteria for temporomandibular disorders, compared with just 25.3 percent of those living in quieter neighborhoods. Bruxism followed a similar pattern, affecting 42.7 percent of the high-exposure group against 14.0 percent of the low-exposure group. Malocclusion, or a misaligned bite, was also more prevalent in the noisy areas, at 52.0 percent versus 26.0 percent. All three comparisons reached a high level of statistical significance, and the researchers confirmed a dose-response relationship, meaning that as noise exposure increased, so did the likelihood of these oral health conditions, a pattern that strengthens the plausibility of a genuine association.

To disentangle the effects of noise from other risk factors, the team performed multivariable logistic regression, a statistical technique that adjusts for the influence of competing variables. The analysis revealed that high noise exposure was the strongest independent predictor of temporomandibular disorders, with an adjusted odds ratio of 3.10 and a 95 percent confidence interval spanning 2.00 to 4.80. In practical terms, after accounting for other measured factors, residents of the noisiest environments faced roughly three times the odds of developing TMD compared with their quieter counterparts. This is a substantial effect size for an environmental exposure, comparable to or exceeding the influence of many traditional risk factors for jaw disorders.

The study then probed the mechanism behind this association using exploratory mediation analysis. The findings pointed to a plausible biological pathway: bruxism and perceived stress together accounted for 41.4 percent of the association between noise and TMD. This pattern is compatible with a well-established model in which chronic noise activates the body’s stress response, elevating cortisol and sympathetic nervous system activity, which in turn promotes muscle tension and involuntary clenching of the jaw muscles. Over time, repeated clenching and grinding can overload the temporomandibular joint, inflame the surrounding musculature, and produce the characteristic pain and dysfunction of TMD. Sleep disturbance, another well-documented consequence of nighttime noise, may amplify this cycle, since poor sleep both heightens stress reactivity and is itself associated with sleep bruxism.

The authors are careful to note an important caveat regarding malocclusion. While the cross-sectional association between traffic noise and misaligned bites was statistically robust, they caution that it more likely reflects pre-existing skeletal or occlusal characteristics of the populations studied than any causal effect of noise. Bite alignment is largely determined by genetics and childhood development, and adults’ jaw structures do not remodel in response to ambient sound. People with certain occlusal patterns may also be more vulnerable to the effects of stress and clenching, which could make them overrepresented among symptomatic residents of noisy areas. The researchers explicitly advise interpreting the malocclusion finding with caution, in contrast to the noise-bruxism-TMD pathway, which is biologically coherent and supported by the mediation results.

As with any cross-sectional study, the design measures exposure and outcomes at a single point in time, which precludes establishing temporal precedence. It remains theoretically possible that people with painful jaw conditions perceive or respond to noise differently, or that unmeasured characteristics of high-traffic neighborhoods, such as air pollution, housing density, or socioeconomic strain, contribute to the observed differences. The mediation analysis, while suggestive, is exploratory and cannot prove causation. Nevertheless, the dose-response gradient, the objective noise measurements, the use of standardized diagnostic criteria, and the alignment with the broader literature on noise and stress physiology collectively lend considerable weight to the findings.

The public health implications are considerable. Environmental noise pollution is already recognized by the World Health Organization as the second most harmful environmental stressor in Western Europe, after air pollution, contributing to cardiovascular disease, sleep disturbance, and cognitive impairment in children. This study extends that concern to an underappreciated domain of health: the masticatory system. If the findings are confirmed by longitudinal research, they would suggest that the burden of traffic noise includes a substantial share of preventable jaw pain and dysfunction, conditions that degrade quality of life, impair eating and speech, and generate significant healthcare costs.

The authors argue that their results support two complementary policy responses. The first is noise abatement: traffic management, quieter road surfaces, speed restrictions, noise barriers, and urban planning that separates residential zones from major thoroughfares could reduce exposure at the population level. The second is targeted oral health screening in high-traffic urban environments, where clinicians might reasonably raise their index of suspicion for TMD and bruxism among patients exposed to chronic noise. For individuals, the study is a reminder that the soundscape of a home is not merely an amenity but a health variable, one that may be quietly shaping the tension carried in the jaw. As cities grow denser and louder, the humble temporomandibular joint may prove to be an unexpected barometer of urban environmental quality, and the study’s message is clear: what harms the heart and the mind through noise may also, quite literally, set teeth on edge.

Subject of Research: The association between environmental traffic noise exposure and temporomandibular disorders, bruxism, and malocclusion in urban adults

Article Title: Environmental noise pollution and its association with temporomandibular joint disorders, malocclusion, and bruxism: A Comparative cross-sectional study of adults in high-traffic and low- traffic areas

Article References: Hasan A. Alshehri, A., Ali F. Alshadidi, A., Aldosari, L. I. N., Kaleem, S. M., Gurumurthy, V., Vyas, R., & Vaddamanu, S. K. (2026). Environmental noise pollution and its association with temporomandibular joint disorders, malocclusion, and bruxism: A Comparative cross-sectional study of adults in high-traffic and low- traffic areas. PLOS One, 21(10), e0360667. https://doi.org/10.1371/journal.pone.0360667

Image Credits: AI Generated

DOI: 10.1371/journal.pone.0360667

Keywords: noise pollution, temporomandibular disorders, bruxism, malocclusion, traffic noise, stress, sleep quality, urban health, public health, cross-sectional study, New Delhi, oral health

The study approaches silence not merely as a measurement in decibels but as a social and legal construct. Since the composer and sound theorist R. Murray Schafer introduced the concept of the soundscape in 1977, geographers have recognized that what counts as silence varies enormously across space and time. A park can feel silent even with children playing, so long as those sounds are considered legitimate. Producing silence, in other words, is a selective activity: it requires deciding which sounds to erase and, by extension, controlling the people or things responsible for them. Cemeteries, as highly regulated spaces designed to connect the living with the absent dead, represent perhaps the purest example of this engineered quiet.

To understand how French law imagines the cemetery soundscape, Dall’Aglio collected 34 sets of local cemetery rules and regulations from municipalities across the Lyon metropolitan area, a territory of 58 municipalities and roughly 1.4 million inhabitants that contains 91 cemeteries. The documents, ranging from a single page to more than 60 pages, were analyzed both qualitatively and quantitatively. The findings were unambiguous. Twenty-five of the 34 documents explicitly forbid making noise, typically with formulaic language prohibiting visitors from screaming, shouting, singing, arguing, or holding loud conversations. Making noise turned out to be among the most heavily regulated behaviors in the entire corpus, outranking even eating and smoking, and second only to the ban on bringing dogs into the cemetery.

The regulation extends well beyond explicit sound bans. Twelve documents forbid meetings within the cemetery that have no connection to funerary matters, effectively silencing friendly or professional gatherings before they can become audible. One document optimistically prohibits disputes outright, while two produce singularly curious rules: one banning telephone alarms and another forbidding laughing. Professional workers face their own acoustic discipline. Stonecutting is forbidden in 17 documents, meaning monument companies must deliver finished gravestones rather than carve them on site. Machinery-heavy work is banned on weekends in 25 documents and on holidays in 27, particularly around All Saints Day. Twenty-five documents forbid driving within cemetery grounds except for funeral processions, removing the mechanical drone of vehicles from the sacred space.

Perhaps most revealing is what the rules permit. Twenty-two of the noise-prohibiting documents carve out an exception for funerary ceremonies, and several specifically allow music. But the framing of that music betrays an implicit religious heritage: one municipality permits no music except religious music, two allow only the recital of psalms, and another restricts singing to liturgic chants, wording strongly associated with Catholic practice. The study argues that this produces a lawscape populated by ghostly, implicitly Christian visitors engaged in solitary silent meditation, while excluding funerary traditions common elsewhere in the world, such as eating at gravesides or ritual dancing, practices that do occur in France on Buddhist graves. The overall principle, the author concludes, is the evacuation of the organic, the bodily, and the mundane from the cemetery soundscape.

But do these ambitious regulations actually produce silence? To answer this, Dall’Aglio turned to publicly available noise data collected by the local association Acoucités, which measured automobile and train noise across the metropolis using fixed and mobile sonometers in 2022. Averaging these measurements within cemetery polygons using GIS software yielded a sobering picture. The average traffic noise level inside Lyon’s cemeteries was 54 decibels, ranging from 41 to 71 decibels. For comparison, those levels correspond to soft music, a lively conversation, or a busy street. Far from being silent, many cemeteries are acoustically indistinguishable from ordinary urban space, and during rush hours the sound of traffic is essentially impossible to escape.

The geography of this noise is no accident, and it tells a two-century-old story. In the early 19th century, French municipalities were pushed by national authorities to relocate cemeteries out of city centers onto secluded, elevated terrain, driven by sanitary fears of miasmas emanating from the dead. This expulsion pushed cemeteries toward the urban margins, where they found themselves neighbors to other space-consuming infrastructure that was likewise relegated to the periphery: landfills, railway lines, and later highways. The pattern persists. The Guillotière cemetery opened a decade after the Lyon-Marseille railway lines beside it were completed. The Bron metropolitan cemetery, built in 1988, was conceived as a way to fill empty land near major roads. A beltway ramp in Villeurbanne was constructed on land originally intended as a cemetery extension. Meanwhile, the quietest cemeteries in the study are either in northern municipalities without major highways or on 19th-century hilltop sites chosen for their fresh air.

This gap between legal promise and acoustic reality leads the study to its most provocative argument. Under French law, the dead occupy a peculiar intermediate status: they are not persons, yet profaning a body is classified in the criminal code as harm to a person rather than harm to property. Since a 2008 law, the respect due to a human body does not cease with death, and violating a deceased person’s funeral instructions is a criminal offense. Yet despite this legal dignity, the dead cannot invoke it. They cannot file complaints, organize, or protest the highways built beside their graves. Drawing on Henri Lefebvre’s concept of the right to the city, the author argues that the dead, as a socially produced category, are deprived of that right in practice: they hold a right not to the city with its silent heterotopias, but merely to the urban, with its continuous flow of noise.

The comparison extends to other groups excluded from urban consideration. Following Christelle Chivallon’s notion of the in-human, beings excluded from humanity in ways that grant humans power over them, the study suggests that noise pollution, like any other form of waste produced by the metropolitan metabolism, is poured into spaces inhabited by those considered lesser citizens or lesser beings. The dead are presumed insensitive, unable to hear or suffer, a sentiment the researcher encountered half-jokingly in conversations with visitors. And because the dead cannot speak, they become prime targets for political instrumentalization: advocates and cemetery managers routinely claim to speak on their behalf, making it difficult to distinguish genuine defense of the dead’s right to rest from political leverage. As Achille Mbembe’s concept of necropolitics implies, the problem is not that the dead are treated like a marginalized group, but that some marginalized groups are treated as if they were already dead.

The study’s conclusion is deliberately exploratory but methodologically suggestive. The failure of cemetery regulations to produce silence says less about the inefficiency of local law than about its virtual nature: rules always require spatial actualization, and the dead cannot perform that work themselves. The changing soundscape is driven primarily by the growing entanglement of cemeteries with the urban fabric, not by any deliberate policy of noise. How to resolve the contradiction between an inherited legal and spiritual order and a contemporary urban and technical order is, the author insists, fundamentally a political question. More broadly, the work proposes that mapping noise pollution, like mapping any urban flow, can reveal geographies of power and relegation, offering geographers a new way to listen to inequality in the city.

Subject of Research: Noise pollution and the legal production of silence in French urban cemeteries

Article Title: When the city wakes the dead – silence, noise pollution, and politics within the contemporary French cemetery

Article References: Dall'Aglio, L. (2026). When the city wakes the dead – silence, noise pollution, and politics within the contemporary French cemetery. Geographica Helvetica, 81(3), 361-373. https://doi.org/10.5194/gh-81-361-2026

Image Credits: AI Generated

DOI: 10.5194/gh-81-361-2026

Keywords: cemeteries, noise pollution, soundscape, legal geography, urban planning, silence, Lyon, right to the city, necropolitics, traffic noise, death studies, France

The methodology behind the study is as elegant as it is demanding. Rather than relying on anesthesia and invasive electrodes, the researchers used behavioral psychophysics, the gold standard for measuring perception in animals. Marine keepers trained each animal to voluntarily participate in the sessions, using positive reinforcement in the form of fish rewards. When a tone was played, the animal pressed a paddle; when no tone was present, it withheld the response. By systematically varying the frequency and intensity of the tones and tracking the animals’ detection performance, the team could plot a hearing threshold curve, known as an audiogram, for each individual. This approach, described by Taronga behavioural biologist Dr Benjamin Pitcher as giving the animals a voluntary choice to participate, ensures that the measurements reflect genuine perception rather than stress-induced artifacts, while keeping the subjects engaged and cooperative throughout the process.

The results revealed a clear peak of sensitivity. Both species were most responsive to sounds around 3.2 kilohertz, a frequency that falls squarely within the range of many natural communication signals and environmental cues. Above and below this optimum, sensitivity declined gradually, as it does in most mammals, with the animals becoming progressively less able to detect very low-frequency rumble and very high-frequency ultrasound. For the Australian sea lion, an endangered species with an estimated population of only about 12,000 animals, this baseline is more than an academic curiosity. Erbe emphasized that understanding what an animal can hear is the indispensable first step in any assessment of noise impacts, because a sound that falls outside an animal’s audible range, no matter how loud, cannot directly disturb its hearing or mask its acoustic signals.

The significance of that principle becomes obvious when the audiograms are overlaid with the spectra of human-made noise. The researchers compared the long-nosed fur seals’ hearing thresholds with the acoustic signatures of boats, ships, aircraft, trains and construction activity, and found that many of these sounds would be clearly audible to the animals when they were hauled out on land. This is a critical finding for coastal management. Pinnipeds spend substantial portions of their lives on beaches, rocky platforms and haul-out sites, often in close proximity to ports, harbors, airports and expanding urban development. If a passing vessel or an aircraft overhead produces sound energy within the animals’ most sensitive frequency band, it has the potential to mask communication between mothers and pups, interfere with the detection of predators or simply impose chronic acoustic stress on animals that are already conserving energy between foraging trips.

For the Australian sea lion, the stakes are particularly high. Endemic to Australian waters and already reduced to a small, fragmented population, the species relies on hearing for a suite of essential behaviors, including communication between individuals, locating prey, navigating through coastal waters and detecting threats. Unlike visual or chemical cues, sound travels efficiently both in air and underwater, making it one of the most versatile sensory channels available to a marine mammal that lives a double life across two media. Any degradation of that channel, whether through masking by vessel noise or disturbance at breeding colonies near busy waterways, could compound the other pressures facing the species, from fisheries interactions to prey scarcity and habitat limitation.

The studies, published separately in the journals Conservation and Animals, document the aerial audiograms of two long-nosed fur seals, Arctocephalus forsteri, and two Australian sea lions, Neophoca cinerea. The distinction between aerial and underwater hearing matters enormously here. Otariids, the family that includes sea lions and fur seals, are amphibious hunters whose ears must function in both environments, and their sensitivity in air and in water can differ substantially. The new measurements establish what these animals can hear in air, which is directly relevant to their time on land, but the underwater half of the picture remains to be filled in. As Erbe and Pitcher both noted, the next step is to understand how noise affects the animals under water, and at what point sound begins to interfere with their behavior or hearing.

That gap is not trivial. Underwater noise from shipping, seismic surveys, pile driving and offshore energy infrastructure has become one of the most pervasive and poorly regulated forms of marine pollution, and regulatory frameworks worldwide increasingly rely on species-specific hearing data to set exposure criteria. An animal’s audiogram determines whether a given noise source is merely background clutter or a genuine hazard. Without baseline hearing data, environmental impact assessments are forced to extrapolate from related species, often from different hemispheres or different ecological niches, introducing uncertainty that can undermine conservation decisions. By providing measured thresholds for two Australian species, the Curtin and Taronga team has given regulators and industry a defensible empirical anchor for the aerial component of those assessments.

The behavioral training regime that made the work possible also deserves attention, because it represents a humane and increasingly favored alternative to traditional methods of measuring animal sensory capabilities. Historically, hearing data for many marine mammals came from stranded or captive animals tested under anesthesia, or from invasive electrophysiological techniques that required restraint. Voluntary psychophysical testing, by contrast, allows the same individuals to be retested over time, produces thresholds that reflect the animal’s full attention and motivation, and doubles as a form of environmental enrichment for the animals involved. The fact that two sea lions and two fur seals could be trained to perform a discrimination task precise enough to yield publishable audiograms speaks to both the flexibility of these animals and the patience of the keepers and researchers who worked with them.

The broader context of the research is a coastline under increasing acoustic pressure. Australia’s shipping lanes are among the busiest in the Southern Hemisphere, coastal development continues to expand around major population centers, and offshore industries are projected to grow as energy demands evolve. Each of these activities adds sound to environments where pinnipeds haul out, breed and rest. For long-nosed fur seals, whose colonies increasingly overlap with urbanized coastlines in southeastern Australia, the finding that boats, aircraft, trains and construction noise fall within their audible range suggests that acoustic disturbance should be considered alongside more traditional concerns such as entanglement and prey depletion when managing haul-out sites and colony buffers.

What makes this research resonate beyond the specialist literature is the simplicity of its central insight: before we can ask whether our noise harms an animal, we must first learn what that animal can hear. For decades, the acoustic worlds of most marine mammal species have remained unmapped, leaving scientists and managers to guess at the boundaries of perception. The Australian sea lion and the long-nosed fur seal have now joined the short list of pinnipeds with measured aerial audiograms, and their contribution may ultimately extend well beyond their own populations. Every species-specific hearing curve that enters the literature strengthens the predictive tools used to protect the many other animals that still live in acoustic silence, at least as far as human science is concerned. As shipping lanes widen and coastal cities grow louder, the quiet paddle presses of four trained animals at Taronga Zoo may prove to be an unexpectedly consequential act of conservation.

Subject of Research: Aerial hearing sensitivity of Australian sea lions and long-nosed fur seals in relation to human-made noise

Article Title: Hearing tests reveal how sea lions and fur seals hear human-made noise

Article References: Hearing tests reveal how sea lions and fur seals hear human-made noise. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Australian sea lion, long-nosed fur seal, audiogram, hearing sensitivity, noise pollution, marine mammals, pinnipeds, Taronga Zoo, Curtin University, behavioral audiometry, coastal development, conservation

The research, published in the journal Environmental Monitoring and Assessment, was carried out by Luka Vukić, Anđela Bratić and Vjekoslav Mario Dragun of the Faculty of Maritime Studies at the University of Split. Between April and September 2024, the team deployed monitoring equipment across ten locations in the city, capturing 154 observations in the port area and 66 along a busy road corridor. They measured fine particulate matter known as PM2.5, coarser particles called PM10, and carbon monoxide, while also logging traffic intensity. Environmental noise was measured in the road corridor, and meteorological variables such as wind speed were recorded to help interpret the results. The approach was deliberately screening-level: rather than running an expensive reference-grade network, the researchers relied on low-cost sensors to make a comparative assessment feasible.

The headline numbers are striking. Mean concentrations of PM2.5 and PM10 were higher in the port area than along the road corridor, at 14.77 and 18.25 micrograms per cubic meter respectively, compared with 11.64 and 14.70 micrograms per cubic meter at the roadside sites. That pattern fits the intuition that ships, with their large engines and sulfur-bearing fuels, should dominate particulate pollution near the waterfront. Yet the story flips for carbon monoxide, a gas tightly linked to combustion engines in vehicles: the road corridor recorded a mean of 5.20 parts per million, nearly double the port figure of 2.91 parts per million. Each transport mode, in other words, leaves its own chemical fingerprint.

But here is where the study becomes genuinely instructive. When the researchers ran formal statistical comparisons between sampling occasions at the two types of location, the differences in PM2.5, PM10 and carbon monoxide were not statistically significant, with p-values of 0.218, 0.227 and 0.505 respectively. The raw averages looked different, but the variability from one measurement session to the next was large enough that the differences could not be confidently distinguished from chance. This is a common and underappreciated problem in urban environmental monitoring: short-duration campaigns capture snapshots of air that is constantly churned by weather, traffic schedules and seasonal shifts, and single averages can mislead.

To dig deeper, the team turned to correlation and regression analysis, and this is where the signal emerged. The number of vessels in the port showed a statistically significant but weak association with PM10 concentrations, explaining only about 8 percent of the variance, with an R-squared of 0.082 and a p-value below 0.001. Vehicle counts, by contrast, were moderately associated with maximum road-noise levels, with an R-squared of 0.236 and a p-value below 0.001. These are modest effect sizes, and the authors are candid about what they mean: neither ships nor cars can be isolated as the dominant driver of pollution in a complex port-city atmosphere using this kind of data alone.

The most robust findings came from multivariable models that accounted for clustering in the data. Even after controlling for other factors, vessel count remained positively associated with both PM2.5 and PM10 in the port area, with p-values below 0.001. Wind speed told the opposite story: higher winds were consistently associated with lower particulate concentrations, a textbook demonstration of atmospheric dispersion at work. When the breeze picks up, it sweeps accumulated particles out of the urban bowl; when the air stagnates, pollution from every source piles up. Meteorology, the study suggests, can mask or amplify the contribution of any single traffic source, which is why the researchers treated weather variables as essential context rather than an afterthought.

One further technical detail deserves attention. The researchers estimated the coarse particle fraction, essentially the share of particulate mass made up of larger particles, and found it to be similar between the port and road environments. This is significant because particle size carries clues about origin. Coarse particles often come from mechanical processes such as brake wear, tire abrasion, resuspended road dust and cargo handling, while fine particles are more characteristic of combustion. A similar coarse fraction in both settings hints that non-exhaust and dust-related processes may be as important as tailpipe or stack emissions, a conclusion that echoes a growing body of literature on non-exhaust vehicle emissions and port dust.

Why does this matter beyond Split? The health stakes are high. Long-term exposure to traffic-related air pollution has been linked in systematic reviews to cardiovascular and respiratory disease, and PM2.5 in particular is implicated in heart disease through well-documented biological pathways. Environmental noise is not a benign companion either; pooled laboratory studies have shown that road, railway and aircraft noise disrupt sleep, and epidemiological work has connected chronic noise exposure to hypertension and other cardiovascular effects. In a port city, residents may be exposed to both stressors simultaneously, and the combined burden could exceed what either source alone would suggest. Studies of European port cities have begun to quantify these maritime health impacts, and the Split data add a Mediterranean data point to that emerging picture.

The study also carries a practical message about monitoring technology. Low-cost sensors have proliferated worldwide, offering cities the ability to deploy dense networks at a fraction of the cost of reference-grade instruments, but they come with well-known calibration challenges and accuracy limitations. The Split team argues that these devices are genuinely useful for comparative, screening-level assessments, the kind of work that identifies hotspots and guides where more rigorous measurement should follow. That is an important middle ground between doing nothing and committing to a full-scale regulatory monitoring network. For many cities in developing regions and smaller ports that lack institutional budgets, this tiered approach may be the only realistic path to evidence-based environmental policy.

Perhaps the deepest takeaway is methodological humility. The authors conclude that the results indicate overlapping rather than uniquely attributable transport-source effects. In plain terms, the air in a port city is a shared product of ships, vehicles, weather, geography and urban form, and no single measurement campaign can cleanly apportion blame. For city planners, that means interventions should be evaluated across both domains at once: shore-power connections and cleaner marine fuels for the harbor, low-emission zones and traffic management for the streets, and noise mapping that treats the waterfront and the roadway as one continuous acoustic environment. For researchers, it means integrated assessments like this one, imperfect as they are, point the way forward. Split’s experience suggests that the question is not whether ships or cars pollute more, but how two overlapping systems of mobility combine to shape the air and soundscape of the cities that host them, and how a modest array of affordable sensors can begin to untangle that knot.

Subject of Research: Integrated assessment of road and maritime traffic impacts on urban air quality and noise in a port city

Article Title: Integrated assessment of road and maritime traffic impacts on urban air quality and noise in a port-city environment

Article References: Vukić, L., Bratić, A., & Dragun, V. M. (2026). Integrated assessment of road and maritime traffic impacts on urban air quality and noise in a port-city environment. Environmental Monitoring and Assessment, 198(11), Article 1139. https://doi.org/10.1007/s10661-026-15986-8

Image Credits: AI Generated

DOI: 10.1007/s10661-026-15986-8

Keywords: air quality, port city, maritime emissions, road traffic, PM2.5, PM10, carbon monoxide, noise pollution, low-cost sensors, Split Croatia, environmental monitoring, shipping

The review, authored by Camille A. Troisi of the Centre d’Étude en Éthologie et Cognition at the Université de Rennes in France, takes a deliberately analytical approach to the problem. Rather than treating social learning as a single, indivisible behaviour, Troisi separates it into two conceptual components: the social component, which concerns the availability and use of information produced by other individuals, and the learning component, which concerns the cognitive machinery that converts observed or transmitted information into lasting behavioural change. This distinction matters because urban factors may act on each component in different, and sometimes opposing, ways.

Social learning is widely predicted to be most useful in novel or variable environments. When an animal faces a new food source, a new predator or a new hazard, copying an experienced individual can be far cheaper and safer than trial-and-error exploration. Urban environments, with their rapid change and abundance of unfamiliar challenges, appear tailor-made for this strategy. Yet, as the review emphasises, whether animals actually rely on social information in cities depends on a chain of conditions: the information must be available, it must be genuinely useful, individuals must be inclined to use it, and they must be capable of learning from it. Disruption at any link in this chain can weaken the whole process.

Pollution emerges as one of the most pervasive urban factors with the potential to interfere with social learning, and Troisi examines it in three distinct forms. Chemical pollution, including heavy metals and endocrine-disrupting compounds, can impair cognition directly, degrading the attention, memory and sensory processing needed to detect and interpret social cues. Noise pollution poses a different problem: acoustic signals are among the most important channels of social information for birds, mammals and other vocal species, and chronic urban noise can mask calls and songs, effectively cutting the bandwidth through which social information flows. Light pollution adds a further layer, altering activity patterns and potentially desynchronising the timing of social interactions between individuals that would otherwise learn from one another.

Food resources represent another pathway with ambiguous consequences. Cities often provide abundant, predictable and clumped food sources, from rubbish bins to bird feeders. On the one hand, such predictability might reduce the need for social learning, since individuals can locate resources through simple routines rather than by following others. On the other hand, concentrated food can increase the frequency of social interactions and produce local traditions, as has been observed in urban birds and mammals that learn novel foraging techniques from conspecifics. The review highlights that the direction of the effect likely depends on how resources are distributed in space and time, and on how competition shapes the willingness of individuals to allow others close enough to be observed.

Temperature is a factor that is easy to overlook but potentially significant. Urban heat islands raise ambient temperatures relative to surrounding rural areas, and temperature influences metabolic rate, activity levels and the timing of behaviour. Because social learning depends on temporal overlap between demonstrators and observers, thermal shifts that alter daily activity patterns could change who meets whom, and when. Warmer nights, for example, may extend or shift activity windows, potentially increasing opportunities for social contact for some species while reducing them for others.

Habitat structure plays an equally complex role. The built environment alters sightlines, creates vertical structures and fragments vegetation, all of which influence how easily animals can observe one another. Dense buildings may block visual transmission of social information, while at the same time creating new vantage points such as ledges, wires and rooftops where animals congregate visibly. Furthermore, structural features of cities can change the value of what is learned: navigating a maze of glass and asphalt may demand entirely new route knowledge, and experienced residents may hold information about safe corridors and hazards that naive individuals cannot easily acquire alone.

Perhaps the most distinctive feature of urban environments is the sheer pace of environmental change. Social learning carries an inherent risk: information can become outdated. In rapidly changing environments, information copied from others may be obsolete by the time it is used, favouring asocial, individual learning instead. Troisi points out that this dynamic could cut against the intuitive prediction that cities should promote social learning. If the urban landscape, traffic patterns or human behaviours that generate rewards and risks change faster than social information can circulate, animals may do better by sampling the environment themselves. The usefulness of social information, in other words, is not a fixed property but a moving target shaped by the rate of change.

Across all of these factors, the review reaches a sobering conclusion. Although there are substantial bodies of research on each individual component — on how pollution affects cognition, on how noise alters communication, on how animals learn socially in laboratory and wild settings — very little empirical work directly examines the relationship between urbanisation and social learning as an integrated whole. Most conclusions about urban social learning are therefore extrapolations rather than demonstrations. The review serves as both a synthesis of what is plausibly known and a roadmap for what remains to be tested, identifying where the logical pathways from urban factors to social information use are strongest and where empirical data are thinnest.

The implications extend beyond academic curiosity. Understanding how animals adapt cognitively to cities is increasingly relevant to conservation, urban planning and the management of human-wildlife conflict. Species that exploit social information effectively may be better equipped to colonise and thrive in urban areas, potentially explaining why some species flourish alongside humans while others retreat. If pollution, noise or the pace of change erode social learning in vulnerable species, cities could be imposing hidden cognitive costs that compound more visible threats. Filling the empirical gap that this review exposes will require targeted experiments comparing social learning performance across urban and rural populations, across gradients of urbanisation, and under controlled manipulations of the specific factors the review identifies. Until such studies accumulate, the question of whether city life makes animals more — or less — reliant on the wisdom of others remains one of behavioural ecology’s compelling open problems.

Subject of Research: The factors in urban environments that influence animals' reliance on and the usefulness of social learning.

Article Title: Factors impacting reliance on, and usefulness of, social learning in urban environments

Article References: Troisi, C. A. (2026). Factors impacting reliance on, and usefulness of, social learning in urban environments. Animal Cognition. https://doi.org/10.1007/s10071-026-02100-1

Image Credits: AI Generated

DOI: 10.1007/s10071-026-02100-1

Keywords: social learning, urbanisation, animal cognition, urban ecology, noise pollution, chemical pollution, light pollution, food resources, habitat structure, environmental change, behavioural ecology, animal behaviour