Spending long hours in an air-conditioned room may feel comfortable, especially during hot weather. But is staying inside a closed, air-conditioned room all day actually bad for your lungs?

Doctors say that the AC itself is generally not the problem. The bigger concern is poor ventilation, dirty filters, dust, allergens, and moisture or mould inside the room. On World Lung Day, experts explain what you should watch out for.

AC itself does not damage your lungs

According to Dr Ajit Kumar from the Department of Medicine at GTB Hospital, Delhi, simply sitting in an air-conditioned room does not directly damage the lungs.

However, if the room remains closed for long periods without adequate fresh-air circulation, indoor air quality can deteriorate. Dust, smoke, allergens and other pollutants can accumulate indoors, potentially affecting respiratory health.

What happens when ventilation is poor?

In a poorly ventilated room, indoor pollutants may remain trapped for longer. This can be particularly uncomfortable for people who are sensitive to dust, allergens or other airborne irritants.

Prolonged exposure may contribute to symptoms such as:

• Cough

• Throat irritation

• Breathing discomfort

• Allergic reactions

• Increased respiratory irritation

This does not mean that everyone who spends time in an AC room will develop lung problems, but maintaining good indoor air quality is important.

Dirty AC filters can make things worse

Regular AC maintenance is essential. Filters can collect dust and other particles over time. If they are not cleaned or replaced as recommended, the accumulated material can affect indoor air quality.

Experts therefore recommend cleaning AC filters regularly and ensuring that the unit is properly maintained.

Watch out for moisture and mould

Moisture and mould are another concern. If there is persistent dampness around the AC, walls or other parts of the room, mould can develop.

Mould and damp environments may trigger allergies and respiratory irritation, particularly in people who are sensitive to them. Any visible mould or persistent dampness should therefore be addressed rather than ignored.

How to keep your AC room healthier

You don't necessarily need to stop using your AC. Instead, focus on maintaining a healthier indoor environment:

• Clean and maintain AC filters regularly.

• Ensure adequate ventilation and fresh-air circulation.

• Keep the room free from excessive dust.

• Address dampness and visible mould promptly.

• Avoid indoor smoking and other sources of air pollution.

• Keep humidity at a comfortable level.

The bottom line

Using an air conditioner is not inherently harmful to your lungs. The bigger issue is spending long periods in a poorly ventilated room with accumulated dust, pollutants, dirty filters or mould.

This World Lung Day, remember that comfortable indoor air should also be clean, fresh and properly ventilated.