air pollution

Posted on Autism

Air pollution emerges as critical environmental risk factor for autism

Scientists reveal complex links between air pollutants and neurodevelopmental disorders in landmark brain medicine emerging topic review
Scientists reveal complex links between air pollutants and neurodevelopmental conditions in landmark Brain Medicine Emerging Topic review

Environmental exposure to air pollutants during critical developmental periods may significantly impact autism risk, according to a groundbreaking Emerging Topic review published in Brain Medicine on 12 November 2024. The study reveals how common air pollutants, including fine particulate matter and nitrogen oxides, can trigger complex biological cascades affecting brain development.

“Various neurological disorders, including autism spectrum disorder, can be linked to this environmental factor,” explains Professor Haitham Amal from the Hebrew University of Jerusalem, who is the senior author of the study. “The timing of exposure is critical, as there is a heightened vulnerability during prenatal development and early childhood when essential neurodevelopmental processes occur.”

The review identifies several critical pathways through which air pollutants may influence autism development:

• Nitrosative stress orchestrated by nitric oxide (NO)

• Neuroinflammation and oxidative stress

• Disruption of neurotransmitter systems

• Epigenetic modifications

• Endocrine system interference

• Metabolic pathway dysregulation

Of particular concern is the finding that smaller particles, especially PM2.5 and NO products, can cross the placenta and affect fetal brain development. This revelation raises important questions about protective measures for pregnant women in highly polluted areas.

“The research suggests that individuals with genetic predisposition to ASD may be more vulnerable to the harmful effects of air pollution exposure,” Professor Amal notes. “This interaction between genetic and environmental factors opens new avenues for understanding ASD’s complex aetiology.”

“My lab has shown that NO plays a major role in autism. However, this study emphasizes the critical role of this molecule and its derivatives on the brain,” Prof. Amal comments. 

The review, first authored by PhD student Shashank Ojha, also highlights promising directions for biomarker development, potentially enabling early identification of at-risk individuals. These findings arrive at a crucial time, as global autism prevalence reaches 1-1.5% of the population.

The implications extend beyond individual health to public policy. How might cities need to adapt their urban planning to protect vulnerable populations? What role could air quality monitoring play in prenatal care? These questions become increasingly urgent as urbanization continues worldwide.

Posted on Autism

New study shows how exposure to air pollution early in life may lead to autism




Polluted Air is a Possible Cause of Dementia

Polluted Air is a Possible Cause of Autism

Exposure to air pollution, particularly traffic-related air pollution, has previously been linked to autism spectrum disorder in epidemiological studies. And now a new animal study from the University of Washington School of Public Health describes a possible mechanism by which this relationship might occur. The study was published Jan. 16 in the journal Brain, Behavior and Immunity.




In an earlier study, researchers from the School found that mice exposed to very unhealthy levels of diesel exhaust, or particulate matter, during pregnancy and early in development displayed behavioral alterations typical of autism spectrum disorder. That is, an increase in repetitive behavior, disrupted communication and deficits in social interactions. Similar hazardous air quality levels have recently been experienced in Seattle during the summer months as wildfires raged through the region.

Yu-Chi (Rachel) Chang, an alumna of the School’s Department of Environmental and Occupational Health Sciences, conducted this study as part of her doctoral dissertation in toxicology.

The current paper describes experiments on mice that show developmental exposure to diesel exhaust could cause subtle changes in the structure of the cerebral cortex (the outer layer of neural tissue of the cerebrum of the brain), as seen in the brains of autistic patients. Researchers also propose a series of biochemical and molecular changes that may underlie such cortical alterations.

“These studies provide an animal model that will allow further investigations on the biological plausibility for an association between air pollution and autism spectrum disorder,” said Lucio Costa, a senior author of the new study and professor of environmental and occupational health sciences at the UW School of Public Health.

“From a public health point of view, it adds to the concerns of air pollution as a possible etiological factor for developmental and neurodegenerative disorders.”




The proposed mechanism begins with increased neuroinflammation and leads to decreased expression of the protein reelin – which activates a signaling pathway required for proper positioning of neurons in the brain – both events common with autism. The mechanism also includes activation of the JAK2/STAT3 pathway, which plays a role in fetal brain development.

Future studies are needed to better understand how gene-environment interaction impacts autism spectrum disorder and to improve protection for vulnerable populations, according to study authors.

Senior author Toby Cole is a research scientist in the Department of Environmental and Occupational Health Sciences at the UW School of Public Health and manager of the rodent behavioral laboratory in the UW Center on Human Development and Disabilities. Co-authors are Ray Daza, former lab manager for the Center for Integrative Brain Research at Seattle Children’s Research Institute, and Robert Hevner, former professor of neurological surgery at the UW School of Medicine. Both are now at the University of California, San Diego.

Posted on Cardiovascular disease

Air pollution and noise increase risk for heart attacks




 

Considering transportation noise should be an integral part of any studies looking at the impact of air pollution on health Jana Sönksen / Swiss TPH

 

 

Where air pollution is high, the level of transportation noise is usually also elevated. Not only air pollution negatively impacts on health, but also car, train and aircraft noise increases the risk for cardiovascular diseases and diabetes, as previous research has demonstrated. Studies investigating the effect of air pollution without sufficiently taking into account the impact that noise exhibits on health, might overestimate the effect of air pollution. These are the results of a comprehensive study conducted by the Swiss Tropical and Public Health Institute (Swiss TPH), which was published today in the peer-reviewed European Heart Journal.
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The study looked at the combined effects of air pollution and transportation noise for heart attack mortality, by considering all deaths that occurred in Switzerland between 2000 and 2008. Analyses that only included fine particulates (PM2.5) suggest that the risk for a heart attack rises by 5.2% per 10 μg/m³ increase in the long-term concentration at home. Studies which also account for road, railway and aircraft noise reveal that the risk for a heart attack attributable to fine particulates in fact increases considerably less; 1.9% per 10 μg/m³ increase. These findings indicate that the negative effects of air pollution may have been overestimated in studies which fail to concurrently consider noise exposure.

“Our study showed that transportation noise increases the risk for a heart attack by 2.0 to 3.4% per 10 decibels increase in the average sound pressure level at home.” said Martin Röösli, Head of the Environmental Exposures and Health Unit at Swiss TPH, and lead author of the published research. “Strikingly, the effects of noise were independent from air pollution exposure.”

Effect of noise and air pollution are additive

The study also found that people exposed to both air pollution and noise are at highest risk of heart attack. Hence, the effects of air pollution and noise are additive. “Public discussions often focus on the negative health effects of either air pollution or noise but do not consider the combined impact.” said Röösli. “Our research suggests that both exposures must be considered at the same time.” This has implications for both policy as well as future research. Hence, Röösli and co-researchers recommend including transportation noise exposure in any further research related to air pollution and health to avoid overestimating the negative effects of air pollution on the cardiovascular system.

Data from across Switzerland




The study included all deaths (19,261) reported across Switzerland from the period 2000 to 2008. The air pollution (PM2.5) was modelled using satellite and geographic data, calibrated with air pollution measurements from 99 measurement sites throughout Switzerland. Nitrogen dioxides (NO2) were also modelled using 9,469 biweekly passive sampling measurements collected between 2000 and 2008 at 1,834 locations in Switzerland. Transportation noise was modelled by well-established noise propagation models (sonRoad, sonRAIL and FLULA 2) by Empa and n-sphere. The air pollution and the transportation noise models were applied for each address of the 4.4 million Swiss adult citizen (aged 30 years and above).