Anju Berardi, Research Student in the Department of Pharmacy, explains how long-term exposure to air pollution – particularly fine particulate matter – may increase the risk of degenerative brain conditions such as dementia.
According to the State of Global Air Report 2025, air pollution was responsible for an estimated 161 million healthy years of life lost due to non-infectious diseases in 2023. This is an increase of 11% from 2000, indicating that the harmful effects of pollution on our health are on the rise.
One of the challenges with research on pollution is the complex and mixed nature of its constituents. There are a variety of man-made and natural sources of pollutants, of which the major contributors include emissions from vehicle exhaust and industrial processes.
The most common types of air pollution worldwide include gases such as nitrogen dioxide and carbon monoxide, as well as solid airborne particles of varying sizes known as particulate matter.
Of these, fine particulate matter is an especially harmful pollutant due to its complex make-up and very small size which allows it to access most areas of the body, including our brains.
Extensive research has established the detrimental effects of living in areas of poor air quality on respiratory and cardiovascular health, increasing the risk of conditions such as lung cancer and stroke.
How air pollution affects the brain
A growing body of evidence highlights that the brain may also be vulnerable to the harmful effects of long-term air pollutant exposure. Inhaling pollutants over many years could increase the chances of a person developing a degenerative brain condition in later life.
In fact, a 2024 report from the Lancet Commission identified air pollution as a key environmental risk factor for dementia which could be prevented. Available statistics show that nearly 1 million people were estimated to be suffering with dementia in 2024, costing the NHS approximately £42.5 billion in the same year alone. Addressing air pollution will therefore likely help to reduce the societal and economic burden caused by worsening brain health outcomes.
However, further work is required to strengthen our understanding of the link between air pollution and brain disease. In particular, we still understand very little about the changes that occur in our brain cells following pollutant exposure, prior to any detectable changes in brain health – including why some individuals with underlying medical conditions (such as high blood pressure) may be significantly more vulnerable, and whether the harmful effects of air pollution on the brain are direct or secondary to other diseases.
Science that shapes policy
Research on the effects of air pollution on human health has already influenced policy, resulting in changes that have reduced emissions and set legal safety standards for pollution levels.
For example, the Ultra Low Emission Zone established in London in 2019 has dramatically improved air quality, resulting in a 54% lower concentration of the harmful gas nitrogen dioxide in central London compared to projected levels without this scheme.
However, available data indicates that air pollution levels in 95% of neighbourhoods in England and Wales remain far from those considered safe, exceeding World Health Organisation air quality guidelines.
This clearly highlights the need to unravel the mechanisms by which air pollution affects our brains and to further inform evidence-based policy changes for public health.
To help address this gap in scientific research, the government’s Medical Research Council has funded a four-year PhD project focussed on how air pollutants affect immune cells that are critical for maintaining healthy brain function.
The project is a collaboration between the University of Reading and the UK Health Security Agency, a government body dedicated to understanding and responding to the threats that environmental hazards and infectious diseases pose to public health. Given this partnership, the project is well-situated to enable conversations about novel research findings with policymakers.
This research is also supported by funding from the Carbon Monoxide Research Trust, a charity that finances and advocates for research into carbon monoxide poisoning, with the ultimate goal of reducing death and injury caused by carbon monoxide. Insights gained from this research will reveal how long-term exposure to carbon monoxide and related pollutants in ambient air affect the ability of immune cells to ensure long-lasting brain function.
Importantly, this work is also championing more humane research practices which reduce the reliance on animal use in biomedical and toxicology research. The use of cell-based methods for understanding the effects of specific pollutants on specific cell types provides a targeted and ethical alternative to animal testing, aligning with the government framework for the Replacement, Refinement and Reduction of Animals in Research (3Rs).
Carrying out research using these novel, scalable technologies will eventually enable the development of screening tools to assess environmental hazard toxicity more efficiently.
This research project holds great potential to improve our collective understanding of air pollution’s effects on the brain, enhancing public preparedness and informing critical public health policy to face the growing challenge presented by poor air quality worldwide.
Feature image by Mario La Pergola on Unsplash