Even short-term rises in air pollution are linked to more asthma emergency visits in Singapore

Duke-NUS Medical School

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A visual abstract showing the study’s findings

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Credit: Duke-NUS Medical School

Even relatively small increases in fine-particle air pollution can be followed by more asthma and chronic obstructive pulmonary disease (COPD)-related emergency department visits according to a nationwide study in Singapore. The increase was most pronounced for asthma, while COPD showed a similar direction of effect but did not reach statistical significance at lower pollution levels.

Published in JAMA Network Open, the study by researchers from Duke-NUS Medical School, Duke University, and Singapore General Hospital analysed 6.5 years of national air quality data alongside almost 75,000 asthma and COPD0F[1]-related emergency department admissions across Singapore’s public hospitals.

The researchers focused on fine particulate matter known as PM2.5, particles measuring 2.5 micrometres or less, that are small enough to travel deep into the lungs. PM2.5 is one of the six pollutants measured in Singapore’s Pollutant Standards Index (PSI), and reported as a 24-hour average, with five bands of air quality ranging from ‘Good’ to ‘Hazardous’.

Over the study period from February 2016 to December 2022, there were 74,839 asthma or COPD-related emergency department visits, of which approximately 43,446 resulted in hospital admission, and 1,369 patients died within 30 days.

Comparing the timing of the emergency department admissions and deaths with daily PM2.5 concentrations, the researchers found a clear relationship between PM2.5 levels and admissions, which peaked two days following the increased air pollution.

For each 10 µg/m³ increase in PM2.5 above the reference level of 15 µg/m³, combined asthma and COPD emergency department visits increased by 3.2 per cent over the following two days.

Asthma-related emergency department visits specifically rose by 4.4 per cent over the same period. COPD-related visits also tended to increase, though the association was less clear at these lower PM2.5 concentrations. The researchers observed stronger evidence of an increase in COPD-related visits at higher pollution levels—suggesting that the respiratory effects of PM2.5 may become more apparent with increased exposure.

The findings provide new insights into the health effects of short-term air pollution in a tropical Southeast Asian setting with relatively low background pollution, a context that remains understudied compared with other regions of the world.

Air pollution in Singapore generally sits at around the current World Health Organization guideline thresholds for PM2.5 exposure, but the city does experience occasional spikes of increased concentrations.

Dr Yohei Okada, corresponding author and Assistant Professor in the Prehospital and Emergency Research Centre at Duke-NUS Medical School said:

“Our findings show that respiratory effects can emerge even after relatively modest increases in PM2.5, and can have measurable impacts on respiratory health. This may only become apparent over the following couple of days. For people with asthma or other chronic respiratory conditions, this reinforces the importance of monitoring air quality advisories and taking precautions early rather than waiting until symptoms worsen.”

The researchers also examined hospital admissions and 30-day mortality following emergency department visits. Hospital admissions showed a similar upward pattern, but the increase was not statistically significant, while no association was observed between PM2.5 levels and 30-day mortality.

The analysis also found no evidence that the risk different significantly according to factors such as sex, age, income, or existing other diseases.

The study was made possible by Singapore’s new national health data platform called TRUST – Trusted Research and real-world data Utilisation and Sharing Tech – which was developed by the Ministry of Health. The platform leverages nationwide linked health data, and this research highlights how TRUST can enable vital population-level research to inform public health policy and healthcare planning.

Professor Marcus Ong, Director of the Health Services Research and Population Health programme at Duke-NUS Medical School, said:

“Haze is not only an environmental issue; poorer air quality can translate into additional demand on emergency healthcare within days. Integrating real-time air-quality information with health data could eventually help hospitals anticipate respiratory surges and give vulnerable patients earlier warning.”

The study could help the development of early warning systems that combine air quality data with weather forecasts to inform vulnerable people – such as those with asthma – and give them the opportunity to take preventive action and avoid triggering an acute health episode.

Professor Lok Sheemei, Interim Vice-Dean in the Office of Research at Duke-NUS Medical School, said:

“This study fills an important knowledge gap in tropical Southeast Asia. The findings could help healthcare providers and policymakers better prepare for breathing-related emergencies, in local settings. It also supports advocating for measures to address and mitigate the root causes of air pollution that crosses national borders in the region.”

The research was supported by the Duke/Duke-NUS Research Collaboration Pilot Project Award.

 

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[1] Chronic obstructive pulmonary disease

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Journal

JAMA Network Open

DOI

10.1001/jamanetworkopen.2026.36306

Method of Research

Observational study

Subject of Research

People

Article Title

Short-Term Exposure to PM2.5 and Emergency Department Visits for Asthma and Chronic Obstructive Pulmonary Disease

 

How New World blackbirds conquered the Americas

University of Würzburg

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Three representatives of the more than 100 species (from left to right): the long-tailed grackle, the Baltimore oriole (mural by Brett Whitacre) and the Eastern Meadowlark. 

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Credit: Axel Arango

Where did the roughly 100 species of New World blackbirds alive today originate, and how did they spread across the Americas? 

Dr. Axel Arango Garcia and Professor Chaitanya S. Gokhale from the Chair for Computational and Theoretical Biology (CCTB) at Julius-Maximilians-Universität Würzburg (JMU) have reconstructed the evolutionary history of this family of birds. Their findings show that the ancestors of today’s species most likely originated in North America and gradually spread southwards over millions of years. The study has been published in the journal Frontiers of Biogeography.

The New World blackbirds – scientifically known as “Icteridae” – are a family of more than a hundred species of songbirds that can be found from Alaska to Tierra de Fuego. Famous members include orioles, grackles and cowbirds, and together they occupy nearly every habitat in the Americas, from the Arctic taiga to the tropical rainforest.

Despite a rich history of ecological, behavioural, and evolutionary studies, the origin of icterids and their biogeographic history has been debated for decades. In 1946, ornithologist Ernst Mayr proposed that icterids originated in South America and spread north in a stepwise manner. In 2015, a study by Barker et al. challenged this hypothesis though. Pointing instead to a North American origin. However, the study left open how and when the birds later spread across the Americas.

Step by step southwards

For their study, the researchers combined distribution data and evolutionary trees for 104 of the 106 currently recognised species. Using a range of statistical models, they reconstructed when and by which routes their ancestors spread across the Americas.

The scenario that best fits the data is one of stepwise southward colonisation: around 7.5 million years ago, the birds reached Mesoamerica and the Caribbean, followed by Amazonia around 6.1 million years ago and the Andes shortly afterwards. Southern South America followed around 4.8 million years ago, with Patagonia reached around 2.7 million years ago. These dates closely reflect the sequence reconstructed in the original study.

“Our findings trace the spread of New World blackbirds across the Americas as a long, gradual process. What is particularly interesting is that their ancestors appear to have reached South America before the present-day Isthmus of Panama had fully formed,” says Arango Garcia.

In South America earlier than previously thought

According to the model, the first dispersal into South America occurred around six million years ago – roughly three million years earlier than previous studies had suggested for this group of birds.

At that time, the present-day Isthmus of Panama had not yet fully formed. The birds may therefore have reached South America by crossing stretches of open water or via existing islands and land connections. At around the same time, open, grass-dominated habitats were expanding in South America. The scientific paper similarly discusses overwater dispersal or pre- or proto-isthmian land connections as possible routes.

“The spread of icterids into South America seem to coincide with the expansion of open, grass-dominated habitats there. It is therefore possible that the birds followed these suitable habitats southwards,” says Axel Arango.

The study cannot, however, demonstrate that these environmental changes actually caused the birds’ southward expansion.

New species mainly evolved locally

The analysis also shows that the colonisation of new regions alone does not explain why new species evolved. Instead, many species arose within regions that had already been colonised. The calculated rates of speciation were broadly similar in North and South America.

Which factors influenced the emergence of new species remains an open question. The authors point, for example, to specialisation in particular foods and habitats, social behaviour, or mate choice. Future studies could incorporate such traits directly into the models, allowing researchers to investigate more precisely why some evolutionary lineages produced more new species than others. This reflects the paper’s conclusion that factors other than geography – potentially including ecological specialisation, social behaviour, and sexual selection – are likely to play an important role in diversification.

Rooted in the classroom

This project has roots in the classroom. Arango has used Icteridae for years as a teaching example. In his classes, icterids have been the protagonists to illustrate macroecological rules, walk students through phylogenetic data analysis, and show how to manage phylogenetic information. The analysis behind this paper took shape while the researcher was preparing course material for a workshop on parametric biogeography, funded by a grant from the “Bayerische Hochschulzentrum für Lateinamerika” (BAYLAT). (https://www.baylat.org/)

“Even after years of working with icterids, it was still striking to discover that their lineages reached South America long before the land bridge closed, and to trace the exact dispersal routes they used to spread all the way to Tierra del Fuego,” says Axel Arango.

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Journal

Frontiers of Biogeography

DOI

10.21425/fob.19.202331

Article Title

The historical biogeography of the New World blackbirds (Icteridae)

 

Pigeon fathers take on more responsibility when times get tough

Unequal co-parenting in urban pigeons can be advantageous

Technical University of Munich (TUM)

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• Male pigeons compensate for food shortages by spending more time incubating eggs, giving the females time to forage for themselves
• Eggs continue to be incubated almost continuously
• Findings provide insights for urban pigeon management

Pigeons adjust the division of parental care effort depending on circumstances. A study by researchers at the Technical University of Munich (TUM) shows that when food becomes scarce, male pigeons spend more time incubating eggs, allowing females additional time to forage for themselves. This behavior allows pigeons to maintain a high level of parental care, even during difficult times. The findings raise welfare concerns with feeding bans.

Together, pigeon parents flexibly divide labor to cooperatively keep the nest warm and protected almost continuously. Females perform most of the incubation before the eggs hatch, regardless of whether food is abundant or scarce, and limited only by their energy reserves. In the study, females spent 81 percent of their time on the nest when food was readily available, while males accounted for only 17 percent. Under reduced food availability, females had lower energy reserves and lowered their incubation effort to 75 percent. Males compensated by increasing their share to 22 percent. This kept overall nest attendance virtually unchanged regardless of food availability.

Female pigeons affected most by local food availability

The researchers studied a total of 75 pigeon nests across three cities with feeding bans. Feeding bans are a common tool used by cities and municipalities to reduce pigeon populations, recognizing that urban pigeon populations are largely sustained by human food. One group consisted of urban pigeons living in managed pigeon lofts with a reliable food supply. The other group nested freely on buildings, such as inside church roofs and on ledges, and had to find food on their own elsewhere. To monitor incubation behavior and the physical condition of the parent birds while minimizing disturbance, the research team installed weight sensors beneath the nests, observing weight changes automatically.

The weight data also revealed that females with access to adequate food supply were about 35 grams, or 10 percent, heavier than females in the unfed control group. The researchers interpret this as an indicator of varying energy reserves resulting from differences in food availability. No meaningful weight differences were found among males, as unfed males had more time to find food elsewhere by incubating so little. Food shortages from feeding bans therefore primarily affected female pigeons.

What feeding bans mean for urban pigeons

“Our study highlights how food limitation affects pigeons,” says Brandon Mak, research associate at the Chair of Terrestrial Ecology at TUM and the study's lead author. “Even under averse conditions, pigeons are able to successfully hatch their offspring.” As a result, young pigeons that hatch may later struggle to find enough food for themselves, subsequently succumbing to starvation in great numbers. He adds: “Against this background, measures that act earlier in the reproductive cycle such as regularly replacing eggs with dummy eggs are a more welfare-friendly way of keeping pigeon populations under control.”

Wolfgang Weisser, Professor of Terrestrial Ecology at TUM, adds: “Living with urban animals requires a deeper understanding of their nuanced behavior, regardless of how we feel about them. Pigeon management is controversial because of how it is done. Our interactions with animals, including modifying their environments, should be done reflexively and include more effective species-specific measures.”

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Journal

Royal Society Open Science

DOI

10.1098/rsos.261123

Method of Research

Observational study

Article Title

When the going gets tough, the dove gets going: feral pigeons maintain nest attendance rates during food shortages with asymmetrical biparental care

Living environment and lifestyle factors may accelerate biological ageing already in early adulthood 

University of Jyväskylä - Jyväskylän yliopisto

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In the study, higher tree cover and vegetation index predicted slower ageing.

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Credit: University of Jyväskylä

Researchers from the Faculty of Sport and Health Sciences at the University of Jyväskylä, Finland, found that biological ageing may accelerate already in early adulthood. In addition to lifestyle factors, environmental exposures and living environment may contribute to faster biological ageing. In the study, childhood and adolescent lifestyle and environmental exposures explained approximately 28% of the variation in biological age at the age of 22. 

Genetics, lifestyles and environmental factors shape how fast our bodies age. Biological ageing begins already before birth, and it can progress faster or slower than chronological age. Faster biological ageing increases the risk of developing age-related diseases earlier in life. 

In a longitudinal twin study conducted at the University of Jyväskylä, researchers examined the exposome, the totality of lifestyle and environmental exposures, and its effect on biological age in young adulthood using machine learning models. In the study, the exposome was captured based on 186 lifestyle and environmental exposures, including lifestyle factors, surrounding greenness, air pollution, and living area sociodemographic factors. 

The researchers found that the measured childhood and adolescent exposures explained approximately 28% of the variation in epigenetic age at the age of 22. 

Biological age is not determined solely by individual choices 

Smoking, alcohol use, and youth unemployment were associated with accelerated biological ageing. In contrast, higher tree cover, vegetation index, and neighbourhood age structure predicted slower ageing. 

The findings highlight the significant impact that living environments and social circumstances have on biological age already in youth. 

“Our results show that biological age is not determined solely by individual choices,” says doctoral researcher Annika Opperbeck. 

“Many of the environmental exposures we identified are structural and systemic, meaning that individuals cannot change them on their own, but society can.” 

“This gives us the opportunity for early interventions to alter long-term health trajectories and reduce health inequalities before they become established,” Opperbeck continues. 

Unexpectedly, larger green space size was associated with accelerated biological ageing, and aerial black carbon predicted slower ageing. According to the researchers, these unexpected findings are likely indicators of underlying rural–urban differences affecting ageing such as socioeconomical and lifestyle differences. 

Further development of machine learning methods will make it possible to examine the complex interactions between environmental and lifestyle exposures in greater detail in the future. 

About the Study:  

This research utilized data from the FinnTwin12 cohort. By tracking 847 participants at ages 12, 14, 17, and 22, the research team analysed 186 unique exposures, including lifestyle habits, green environments, air pollutants, and sociodemographic factors. 

It is the first publication from Annika Opperbeck's doctoral dissertation, which investigates the interplay between the exposome, genetics, biological ageing, and obesity. The article was recently published in the high-impact journal Environment International. 

The study is a collaborative effort by the University of Jyväskylä’s Faculty of Sport and Health Sciences and Faculty of Information Technology, alongside researchers from the Institute of Molecular Medicine Finland (FIMM) at the University of Helsinki, University of Oulu, Xinjiang Medical University, and the Wellbeing Services County of Central Finland. 

The research was presented at the Global Exposome Summit 2026 in Barcelona and the Paula Rantakallio Symposium in Oulu (both oral) and at the Global Exposome Symposium for Brain Health 2026 in Bordeaux, where Annika Opperbeck was awarded 3rd prize in the early-career researcher competition.  

The study’s first author, PhD researcher Annika Opperbeck, is a member of the GenActive research group led by Associate Professor of Health Promotion Elina Sillanpää. The group explores the genetic and lifestyle factors that shape biological ageing, health, and functional capacity.  

The research was funded by Emil Aaltonen Foundation, Rehabilitation Foundation Peurunka, Research Council of Finland, Juho Vainio Foundation, Päivikki and Sakari Sohlberg Foundation, Sigrid Jusélius Foundation, Yrjö Jahnsson Foundation, Liv och Hälsa sr., Horizon Europe framework program, EC FP5 GenomEUtwin, EC Horizon 2020 Equal Life, EC MC ITN EPITRAIN, National Institutes of Health/National Heart, Lung, and Blood Institute, and University of Helsinki Research Funds. 

Data collection in the FinnTwin 12 study has been supported by the National Institute of Alcohol Abuse and Alcoholism and the exposome data were curated in close collaboration with the Equal Life project.  

 

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Journal

Environment International

DOI

10.1016/j.envint.2026.110430

Subject of Research

People

Article Title

Exploring the exposome and unexplained variance in epigenetic ageing – Insights from a longitudinal twin study in adolescence and early adulthood

 

Insect declines threaten wildlife far beyond insect world

Major global analysis shows insects provide diverse benefits for other animals – from food and shelter, to protection and even medicines.

UK Centre for Ecology & Hydrology

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From grizzly bears and chimpanzees to geckos and poison dart frogs, the lives of tens of thousands of animal species depend on insects and other invertebrates not just for food. They provide, homes, medicines, sanitation and chemical self-defence, often living alongside each other in mutually beneficial relationships.  

Scientists are now warning that widespread insect declines will therefore have far-reaching impacts on other species. An international research team carried out the most comprehensive global scientific analysis to date of the impacts of insects on wildlife, led by the UK Centre for Ecology & Hydrology (UKCEH) and Binghamton University, USA. 

The scientists reviewed evidence from almost 300 studies published over the past 75 years relating to land and freshwater wildlife, including mammals, birds, amphibians, reptiles and fish. It found nearly three-quarters of studied wildlife species eat invertebrates – mainly insects – and over two-fifths exclusively so.

Many animals also rely on foods that exist only because insects pollinate plants or disperse seeds.  Some species have developed remarkable adaptations for capturing them, from the projectile tongues of amphibians and chameleons to birds that have learnt to remove bee stings before eating them. 

But the study, published in Nature Reviews Biodiversity, also identifies many ways that insects support wildlife beyond simply providing food. 

• Providing homes: Wildlife use insect-built structures, particularly termite mounds and ant nests, for shelter, protection from predators, breeding grounds or laying eggs.   
• Chemical defence: Some animals, such as poison dart frogs, accumulate toxins from the ants and beetles they eat and secrete them, making themselves less appealing to predators.
• Health and sanitation: Insects can reduce disease risk through the removal or drying of dung, which also kills parasites. Beetles prey on the larvae of blowfly and other pests, protecting birds and mammals from biting insects and disease. Chimpanzees apply insects to open wounds and some birds, reptiles, amphibians, rodents and primates use ants for grooming. 

The paper’s co-lead author Dr Rob Cooke, a senior ecologist at UKCEH, said: “Our study presents the most holistic picture of interactions between insects and wildlife to date. It highlights the remarkable and often overlooked ways that insects support other animals, and the extraordinary relationships between them.  

“Widespread insect declines globally are likely to have far-reaching effects on wildlife. Beyond reducing an essential food source, losses of insects risk changing ecosystems, disrupting pollination and seed dispersal, weakening sanitation, and altering the many interactions that help ecosystems function.  

“We therefore hope our research strengthens the message that protecting insect populations is essential for protecting wider biodiversity.”

Helpful housemates 

Some species of wildlife live alongside insects in mutually beneficial relationships. Moths have been found in owl and kingfisher nests, where they decompose fur, crushed feathers, pellets and faeces. They also live on the backs of brown-throated sloths where they deposit nitrogen in their fur and spur algal growth, a key food source for their hosts. 

The study does, though, also point out the negative impacts. Although insects generally do not eat other animals, it does occur, such as dragonfly nymphs eating tadpoles and small fish and mantids sometimes capturing hummingbirds and other small birds. Ants and wasps have been reported to attack lizards, birds and mammals. 

Meanwhile, different species of mosquitoes transmit avian malaria and West Nile virus to birds, or fungus to frogs, and fleas pass on pathogens to mammals. 

Dr Eliza Grames of Binghamton University, co-lead author of the paper, concluded: "Changes in insects can have massive consequences for food webs and ecosystems. Declines in insect populations could risk destabilizing some of the most fundamental processes that the natural world depends on." 

ENDS

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Journal

Nature Reviews Biodiversity

DOI

10.1038/s44358-026-00201-w

Method of Research

Systematic review

Subject of Research

Animals

Article Title

The importance of insect biodiversity for vertebrates

 

Insects are essential to vertebrate life — as food, shelter and medicine

Binghamton University, State University of New York biologists co-author a review paper on the importance of insect diversity in a time of decline

Binghamton University

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A new paper featuring faculty at Binghamton University, State University of New York, reveals that vertebrates like sloths rely on insects for a variety of purposes.

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Credit: “Hoffmann's Two-toed Sloth (Choloepus hoffmanni) 霍夫曼兩趾樹懶 & Sloth Moths (Cryptoses choloepi) 樹懶蛾” by Dash Huang, CC BY-NC-SA 2.0

While insects provide an essential food source for many vertebrate species, they’re more than just a protein-laden snack.

Chimpanzees use them to sterilize wounds, and herons as fishing bait. Sloths rely on moths to maintain the algae in their fur, which they then eat. Birds and reptiles lay their eggs inside the temperature-controlled sanctuary of termite mounds, while some desert frogs reside in ant nests because of the humidity.

“Insects are sometimes called the ‘little things that run the world’ because they are so important to life on Earth,” said Binghamton University, State University of New York Assistant Professor of Biological Sciences Eliza Grames, the co-lead author of “The importance of insect biodiversity for vertebrates,” published Sept. 30 in Nature Reviews Biodiversity. “We often hear about their importance as pollinators, or decomposers, or food for insectivores like birds and bats, but we forget about all the other things they do for us and for other species.” 

A collaborative effort with authors from eight countries, the review paper was led by Grames along with Rob Cooke, an ecological modeler at the UK Center for Ecology and Hydrology, and UConn Professor of Ecology and Evolutionary Biology Chris Elphick. 

Additional Binghamton authors include Assistant Professor of Biological Sciences Lindsey Swierk and biological sciences alumni Julianna Yager, MS ’25, and Suyeon Jang, ’25. Jang, an undergraduate with a painting minor, also created the paper’s main illustration as an independent study project. 

The review article consolidates hundreds of disparate studies conducted across decades, highlighting the importance of insect biodiversity in supporting vertebrate life. The project began in 2022 with the creation of the National Science Foundation-funded Status of Insects: An International Research Coordination Network, a direct result of Grames’ work as a doctoral student in Elphick’s lab. 

A better understanding of the diverse roles that insects play in the lives of vertebrates is essential for designing effective conservation strategies. Elphick, an ornithologist, said that he hopes the review will foster increased collaboration between scientists who study vertebrates and those who study insects.

“If you want to have vertebrates, then you’ve got to be thinking about insect conservation, and we don’t do that nearly enough,” he said.

There are an estimated 14 to 30 million species of insects in the world, and they play a major role in the health and function of ecosystems. They provide food to species ranging from hummingbirds to grizzly bears, enable the existence of other food sources through pollination, and produce substances such as honeydew, honey, and wax that are also consumed by other species.

Birds use spider and insect silk in their nests, which they sometimes situate near stinging insects such as wasps for extra protection. More than 200 bird species use crushed ants for grooming, and a variety of vertebrate species time their breeding season to coincide with seasonal insect abundance. Go back far enough, and insects once lived inside dinosaur nests, cleaning them out; it’s a service they still perform in some owl and kingfisher nests, according to Grames. 

But few scientific studies consider the decline of insect populations on vertebrate species, other than as a reduction in a species’ food supply, according to the paper. Some insect populations have experienced alarming declines in recent decades, which will ultimately affect the vertebrate species that rely on them. 

“We’re losing insects at a rate of about 1-2% per year,” said Grames. “When you scale that up across a few decades, we’re talking about a major change to ecosystems. Insect conservation should be a top priority for anyone worried about the future of biodiversity.”

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Journal

Nature Reviews Biodiversity

Method of Research

Literature review

Subject of Research

Animals

Article Publication Date

30-Sep-2026