Can sitting under an air conditioner all day ruin your lungs?

New Delhi: For many urban residents, turning on the air conditioner feels routine. It cools hot homes, makes sleep easier on sultry nights, and lightens the strain of long workdays. Yet behind this comfort sits a quieter concern—constant dependence on air conditioning may slowly undermine respiratory health. In recent years, doctors have been seeing a rise in cases of hypersensitivity pneumonitis—an immune-related lung condition that often goes unnoticed until it becomes serious. The connection? Poorly maintained air conditioners and inadequate ventilation in tightly sealed urban homes.

Dr. A Jayachandra, Clinical Director and Senior Interventional Pulmonologist, CARE Hospitals, Banjara Hills, Hyderabad, explained how air conditioners can affect lung health.

The Hidden Life Inside Your AC

Air conditioners work by recirculating indoor air. Unlike an open window that lets in fresh flow, an AC pushes the same cooled air again and again through filters and ducts. When these filters are clogged or ignored, they turn into spaces for mold, bacteria, and fine organic particles. Each breath then carries those irritants into the lungs.

For most people, a single exposure may cause nothing more than a mild cough or irritation. For some people, breathing in these particles again and again can set off hypersensitivity pneumonitis. It is an allergic response deep in the lungs, leading to inflammation of the tiny air sacs (alveoli) where oxygen moves into the blood. With time, this irritation can turn into scarring, making normal lung function more difficult.

Why Urban Homes Are at Higher Risk

The issue is greater in today’s city apartments. Older houses once had higher ceilings and steady airflow, but modern homes are compact, sealed, and rely heavily on cooling systems. As pollution rises, many keep windows closed to block dust and smoke. This may cut outdoor exposure, yet it leaves indoor air stagnant and allows allergens to build up.

Moreover, many high-rise buildings use centralized cooling systems that serve multiple units. If even one system is poorly maintained, mold spores or other contaminants can circulate throughout the building, affecting dozens of residents.

The Subtle Signs to Watch For

Hypersensitivity pneumonitis does not appear overnight. Its symptoms often mimic those of a persistent flu or seasonal allergy:

• Dry cough that lingers for weeks
• Shortness of breath on mild exertion
• Tightness in the chest
• Fatigue or unexplained malaise
• Recurring fever or chills after spending time in a cooled environment

Because these signs are so nonspecific, many people dismiss them or treat them with over-the-counter medicines. It is only when symptoms worsen—sometimes progressing to severe breathlessness—that patients seek medical help. By then, damage to the lungs may already be advanced.

A Closer Look at Prevention

The reassuring part is that most cases can be prevented with steady, basic care. The first safeguard is regular cleaning and servicing of air conditioners. Filters need washing or replacement every few months, depending on use, and ducts should be inspected for dampness. In humid regions, dehumidifiers can help, since excess moisture speeds up mold growth.

Just as important is keeping some natural ventilation. Even opening a window briefly helps stale air move out and lowers the build-up of indoor allergens. Plants, while useful in moderation, must be tended with care, since overwatering can release fungal spores into the air inside.

The Role of Medical Awareness

Doctors are now urging greater awareness of indoor environmental health. Too often, patients with hypersensitivity pneumonitis are being treated as having asthma or an infection with no improvement. A detailed history—asking about living conditions, AC use, or workplace exposures—can reveal the true culprit. High-resolution imaging and lung function tests further confirm the diagnosis.

Early detection is vital. In the beginning, hypersensitivity pneumonitis can improve if the source of exposure is eliminated. But if the inflammation continues unchecked, it may cause lasting scarring (pulmonary fibrosis), leaving patients with ongoing breathing trouble.

Striking a Balance

Air conditioning itself is not the enemy. In fact, for individuals with asthma, cooled air often provides relief by reducing outdoor pollutants and humidity. The danger arises when we use AC units as sealed boxes of comfort without respecting the need for air quality. Cooling systems should work hand-in-hand with ventilation, cleanliness, and mindful living habits.

Urban life demands compromises, but health should not be one of them. Taking small, preventive measures—regular servicing, allowing air circulation, and paying attention to early symptoms—can protect our lungs while letting us enjoy the comfort of modern living.

Your home should be a place of healing, not a silent source of harm. If you find yourself breathless, coughing without reason, or repeatedly falling sick after long hours indoors, it may not be “just the weather.” The air you breathe is as important as the food you eat. Caring for your air conditioner, and by extension your indoor environment, is not merely about comfort—it is about safeguarding the very lungs that carry you through life.

Reference Link

https://www.tv9english.com/lifestyle/can-sitting-under-an-air-conditioner-all-day-ruin-your-lungs-article-10873092.html