How heavy metals in polluted air trigger fatigue, headaches and brain fog

Beyond PM2.5 and PM10, polluted air carries neurotoxic metals like lead, arsenic and cadmium that inflame the brain, disrupt energy pathways and trigger fatigue and fogginess on high-AQI days

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Many people notice feeling unusually tired, unfocused or foggy during pollution. It is partly because polluted air does not just look dirty; it carries invisible heavy metals that slip deep into the lungs, enter the bloodstream and reach the brain.  According to Dr Kinjal Modi, Consultant, Pulmonary Medicine, P D Hinduja Hospital, Khar, invisible neurotoxic particles such as lead, arsenic, cadmium and nickel ride on polluted air like hitchhikers, slip past the lungs’ defences and leave people wondering why they feel foggy, tired, irritable or just “off”.

Are AQI numbers hiding more harmful pollutants?

Dr Modi highlights that AQI was designed to simplify pollution trends using a single number, colour code and broad pollutant categories. It tracks major regulated pollutants such as PM2.5, PM10, ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide.

 

However, pollutants such as lead, arsenic, chromium, cadmium, volatile organic compounds, benzene and ultrafine particles do not appear on AQI apps even though they are present in the air, especially on high-pollution days.

 

As Dr Modi explains, the absence of measurement does not mean the absence of impact. These metals still enter the body and still cause damage.

Which heavy metals rise during polluted days and how do they enter the body?

On poor AQI days, urban air often shows increased levels of lead and manganese from vehicles and industrial activity.

 

Other metals also spike:

• cadmium from smelting and waste burning
• arsenic from coal and industrial emissions
• nickel from fuel combustion and brake wear

These metals latch on to PM2.5, allowing them to reach the deepest parts of the lungs. Once inhaled, they embed in the alveoli, slip into nearby capillaries and then enter the bloodstream. Some metals, such as mercury vapour, have absorption rates up to 80 per cent.

 

Once inside, they travel to the liver, kidneys, bones and the central nervous system.

How is heavy-metal toxicity different from routine PM2.5 exposure?

Particulate matter irritates and inflames the respiratory and cardiovascular systems.

 

Heavy metals behave differently. Dr Modi explains that they accumulate, persist and interfere with the chemistry of organs. “Lead disrupts nerve signalling. Cadmium can damage bones and kidneys. Arsenic affects the lungs and skin. Some of these metals are carcinogens. This is not just surface-level inflammation; it is systemic, slow and far-reaching,” he says.

How do these metals reach the brain and cause fogginess or fatigue?

The brain is protected by the blood–brain barrier, but heavy metals can exploit nutrient transport pathways or disrupt the barrier when concentrations are high.

 

“Once inside, they create oxidative stress, inflame neural tissue and interfere with mitochondria, the tiny energy factories in brain cells. This disruption is closely linked with fatigue, headaches, slow thinking, poor focus and that ‘walking-through-mist’ feeling many complain about during polluted days,” Dr Modi explains.

 

Exposure may trigger:

• headaches
• fatigue
• irritability
• temporary memory lapses
• difficulty concentrating
• tremors
• slow coordination

Different metals cause different patterns, but they commonly affect mood, cognition and motor control shortly after exposure.

Why are people with mineral deficiencies more vulnerable?

Dr Modi explains that when the body is low in iron or zinc, it absorbs metals like lead or cadmium more readily because the body mistakes them for the minerals it lacks. B-vitamin deficiencies do not increase absorption but can worsen the effects by weakening metabolic resilience.

Do air purifiers remove heavy-metal particles indoors?

Yes. Dr Modi emphasises that High-Efficiency Particulate Air (HEPA) filters can trap metal-laden PM2.5, cleaning indoor air of both particulate matter and its toxic passengers. However, purifiers must be used in sealed rooms with correct filter grades and regular replacement. A poorly used purifier is little more than a noisy fan. 

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This content is for informational purposes only and is not a substitute for professional medical advice.