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BEYOND THE LUNGS: Air Pollution Damages Heart and Brain
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BEYOND THE LUNGS: Air Pollution Damages Heart and Brain

Uncategorized December 5, 2025 , by

Clean air is not a luxury. It is a fundamental determinant of human health, cognitive vitality and longevity….

By Dr Amit Dias

AMIDST recent reports of escalating air pollution across the country, especially in major urban centres, the conversation about its impact must shift. Air pollution is a systemic poison, targeting not only our lungs but—crucially—our heart and brain as well. This grave reality demands immediate, concerted action. Dr Amit Dias, who was part of the 2020 Lancet Commission that highlighted this link between air pollution and cognitive decline, unmasks the silent killer – air pollution
The Medical Scientific Basis: How Pollutants Invade Our System
FOR decades, air pollution was primarily viewed as a respiratory hazard. However, modern medical science has revealed a much more insidious mechanism of action, primarily driven by microscopic particles.
The culprits are Particulate Matter (PM), particularly PM 2.5 (particles with a diameter of 2.5 micrometres or less) and ultrafine particles (UFP), which are less than 0.1 micrometre. To give you an idea of the size and put this in perspective, PM 2.5 is about 30 times smaller than a single strand of human hair!!

The Crossover Mechanism
WHEN inhaled, these tiny particles penetrate deep into the lungs’ alveoli, the delicate air sacs responsible for gas exchange. Unlike larger particles that are trapped and cleared, PM2.5 and UFPs are so minuscule that they can crossover from the lungs directly into the bloodstream.
Once in the circulatory system, they do not simply travel inertly. They trigger a cascade of biological damage:

  1. Inflammation and Oxidative Stress: The body registers the particles as foreign invaders, initiating a widespread inflammatory response and massive production of Reactive Oxygen Species (ROS), leading to oxidative stress.
  2. Endothelial Damage: This inflammation and oxidative stress primarily target the endothelium, the delicate inner lining of the blood vessels. This damage, known as endothelial dysfunction, is the foundation of many chronic diseases.
  3. Systemic Impact: The compromised blood vessels and systemic inflammation act as conduits for damage throughout the body, including the most vital organs.

Air Pollution and Cardiovascular Disease
THE link between dirty air and heart disease is now irrefutable. Air pollution is a major, yet often overlooked, risk factor for cardiovascular mortality.
Atherosclerosis and Heart Attacks
Chronic exposure to PM 2.5 accelerates atherosclerosis (hardening and narrowing of the arteries), which is the principal cause of heart attacks and many strokes.
• The inflammation caused by PM 2.5 makes the endothelial cells sticky, facilitating the buildup of plaque (fats, cholesterol, and other substances) on the artery walls.
• The continuous stress can also destabilise existing plaque, leading to its rupture and the formation of a clot, which can completely block blood flow—a heart attack.
• Global health data attributes a significant portion of the global burden of ischaemic heart disease and stroke to ambient air pollution.

Hypertension and Heart Failure
Air pollution also plays a key role in the development and worsening of other heart conditions:
• Hypertension (High Blood Pressure): The damage to the endothelium impairs its ability to produce nitric oxide, a molecule critical for relaxing and widening blood vessels. This results in stiffer blood vessels and elevated blood pressure, significantly increasing the risk of heart failure and stroke.
• Heart Failure: The increased workload on the heart, resulting from hypertension and vessel damage, can lead to the thickening and enlargement of the heart muscle (ventricular hypertrophy), eventually causing the heart to lose its ability to pump effectively.

The Silent Attack on the Brain: Stroke and Dementia
The brain, with its dense network of blood vessels, is highly vulnerable to systemic inflammation and endothelial damage.
Stroke
Air pollution exposure has been linked to an increased risk of stroke. The same mechanisms that cause heart attacks—plaque buildup and clot formation—can occur in the blood vessels supplying the brain, leading to an ischaemic stroke. Furthermore, weakened blood vessels can rupture, causing a bleeding or haemorrhagic stroke.

Dementia and Cognitive Decline
As highlighted in the 2020 Lancet Commission Report, air pollution has been added to the list of modifiable risk factors for dementia.
• Vascular Dementia: Reduced blood flow to the brain, exacerbated by air pollution-induced atherosclerosis and hypertension, damages brain tissue, leading to vascular dementia.
• Alzheimer’s Disease: Pollutants may also directly enter the brain via the olfactory nerve or the bloodstream, crossing the blood-brain barrier. Once inside, they trigger neuroinflammation and oxidative stress, mechanisms implicated in the accumulation of characteristic dementia markers like amyloid-beta plaques and tau tangles.
• The evidence specifically suggests that reducing exposure to air pollution is an essential, preventative measure against cognitive decline and dementia.

Air Pollution and Harm to Children
Children are among the most vulnerable, as their organs are still developing and they breathe faster, inhaling a greater volume of air relative to their body size.
• Impaired Lung Development: Exposure during pregnancy and early childhood can lead to premature birth, low birth weight, and stunted lung growth, predisposing them to asthma and chronic respiratory diseases later in life.
• Neurological and Cognitive Effects: Research suggests a link between early-life exposure to pollutants and reduced cognitive function, including memory impairment, and an increased risk of conditions like Attention-Deficit Hyperactivity Disorder (ADHD) and even early signs of neurodegeneration. Air pollution impacts children’s health for the rest of their lives.

Air Pollution and Cancers
Air pollution, particularly PM2.5, has been classified as a Group 1 carcinogen, meaning it is known to cause cancer in humans.
• Lung Cancer: The fine particulate matter carries carcinogenic compounds deep into the lungs, where they can induce chronic inflammation and directly damage DNA, leading to mutations. In many polluted regions, the incidence of lung cancer among non-smokers—particularly the subtype adenocarcinoma—is tragically on the rise, underscoring air pollution as a primary driver.

The Pollutants of Concern and The Rise in Pollution
The air is a complex cocktail of poisons, but key pollutants of public health concern include:
• Particulate Matter PM10 and PM2.5: Solid and liquid particles; the most dangerous for health. Sources include vehicle exhaust, industrial emissions, construction dust, and burning biomass (like crop residue).
• Nitrogen Dioxide (NO2): A gaseous pollutant primarily from burning fossil fuels in vehicles (especially diesel) and power plants. It irritates the airways and contributes to the formation of PM2.5.
• Sulphur Dioxide (SO2): Released from burning fossil fuels containing sulphur (coal, oil), mainly by industry and power generation.
• Ozone (O3): A secondary pollutant formed when nitrogen oxides and Volatile Organic Compounds (VOCs) react in the presence of sunlight. At ground level, it is a key component of smog and irritates the respiratory system.
• Carbon Monoxide (CO): An odourless, toxic gas from incomplete combustion of fuel.
Why is Pollution Increasing?
The increase in air pollution is primarily driven by:

  1. Unregulated/Rapid Urbanisation: Proliferation of private vehicles and construction activity without strict emission controls.
  2. Reliance on Fossil Fuels: Continued use of coal for power generation and petroleum products for transport and industry.
  3. Agricultural Practices: Seasonal burning of crop residues.
  4. Inefficient Waste Management: Open burning of municipal and industrial waste.
  5. Household Air Pollution: Millions of people globally rely on polluting fuels (kerosene, biomass, coal) for cooking and heating, contributing significantly to both indoor and outdoor air pollution.

How to Identify Signs of Air Pollution Exposure
While the most severe damage is silent and internal, certain symptoms should raise concern, especially during high-pollution days:
• Respiratory: Persistent cough, shortness of breath, increased severity or frequency of asthma attacks, bronchitis.
• Cardiovascular: Chest pain, heart palpitations, or sudden onset of high blood pressure (especially in the elderly or those with pre-existing conditions).
• Neurological: Headaches, fatigue, difficulty concentrating, or sudden confusion.
• General: Eye irritation, sore throat, and skin allergies.

The Way Forward: Prevention at All Levels
Global health estimates link air pollution to an alarming number of premature deaths annually—a figure surpassing global deaths from tobacco. Addressing this crisis requires a coordinated approach from the government to the individual.
Government and Policy Implications
Governments must treat air quality as a public health imperative, not just an environmental issue.

  1. Policy for Clean Energy Transition: Introduce stringent deadlines and subsidies to rapidly replace fossil fuels with renewable energy sources (solar, wind) for power generation and industrial operations.
  2. Sustainable Transport: Invest heavily in and promote clean public transport (electric buses, trains). Implement stricter vehicle emission standards and promote walking and cycling infrastructure. Consider carbon taxes to internalise the social cost of pollution.
  3. Strict Enforcement and Monitoring: Establish independent environmental watchdogs to enforce emission standards for industry and construction sites. The implementation of robust, real-time air quality monitoring networks should be mandatory, with data made easily accessible to the public.
  4. Urban Planning: Redesign urban layouts to integrate green spaces (which absorb pollutants) and control industrial zoning away from residential areas.
  5. Address Household Pollution: Launch national-level schemes to ensure universal access to clean household energy for cooking and heating.

Individual Actions
While systemic change is crucial, individual choices aggregate to create a larger impact. Our health is in our hands.

  1. Reduce Vehicle Use: Use public transport, cycle, or walk whenever possible. Carpool, and avoid engine idling.
  2. Energy Conservation: Reduce electricity consumption (which often relies on fossil fuel power plants). Use energy-efficient appliances.
  3. Avoid Burning: Never burn garbage, biomass, or leaves; use designated municipal waste disposal.
  4. Monitor and Mitigate Exposure: Check the Air Quality Index (AQI). On days of severe pollution, reduce strenuous outdoor activity and wear high-efficiency masks (e.g., N95) outdoors. Use indoor air purifiers with HEPA filters.
  5. Advocacy: Demand and support policies that prioritize clean air and environmental justice in your local community.
    The overwhelming medical evidence points to a single conclusion: clean air is not a luxury; it is a fundamental determinant of human health, cognitive vitality, and longevity. By recognising the full extent of the damage—from the lungs to the heart and the brain—we are compelled to act now to secure a healthier future for all.

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