Pollution, smoking, and that cough: It may be time for a lung function test

If your cough just won't go away, it might be more than the season or smog; doctors explain when it's time to get a lung function test

That persistent tickly cough you’re brushing off as seasonal or smog-related may be your body’s early warning sign.

 

According to Dr C C Nair, Internal Medicine Specialist at Lilavati Hospital & Research Centre, a cough lasting more than eight weeks in adults is classed as chronic and needs medical evaluation.

 

“Even before that, if you notice breathlessness, during exertion or at rest, such as wheezing, chest tightness, blood in sputum, recurrent fevers, unexplained weight loss, or a cough that disturbs your sleep, don’t wait,” he warns.

 

These are signs your airways might be under stress from an underlying condition like asthma, chronic bronchitis, or infection,  and a lung function test (spirometry) could be the first step toward clarity.

 

Can pollution damage even healthy lungs?

Long-term exposure to fine particulate matter (PM2.5), especially in cities with heavy traffic, can significantly reduce lung growth and function, explains Dr Nair.

 

“Even young, non-smoking adults can show early signs of lung ageing,” he says. “Over time, pollution accelerates the decline in lung capacity and raises the risk of chronic obstructive pulmonary disease (COPD) and respiratory symptoms.”

 

Even ambient and household air pollution can both cause or worsen asthma-like symptoms and increase COPD risk, he adds. While pollution may not harm every individual as severely as heavy smoking, it is now a well-established contributor to obstructive lung disease and lung cancer, even among non-smokers.

What if you smoke or recently quit? Should you still get tested?

Major global panels like the US Preventive Services Task Force do not recommend population-wide screening of healthy adults.

 

But in clinical practice, doctors often recommend baseline spirometry for:

• Smokers or ex-smokers over 40
• Those with high cumulative tobacco exposure
• People in dusty or chemical-heavy jobs

“If a smoker develops cough, breathlessness, or chest tightness, even if mild, it is time for testing,” says Dr Nair. Early diagnosis can guide treatment and strengthen quit-smoking motivation.

Does secondhand smoke raise your risk too?

Passive smoke exposure also increases the risk of chronic cough and airway disease. Dr Nair advises that “anyone regularly exposed to secondhand smoke should have a lower threshold for testing if symptoms arise.”

 

Universal screening isn’t routine, he clarifies, but vigilance is key.

What exactly does a lung function test involve?

A spirometry test measures how much air you can inhale and exhale, and how quickly.

 

“It’s a simple, office-based test that gives vital clues to airflow obstruction, conditions like asthma or COPD,” explains Dr Nair.

 

Advanced tests like body plethysmography or DLCO are used when spirometry is unclear or when interstitial or restrictive lung diseases are suspected.

 

In India, spirometry is now widely available and relatively affordable. Ensure it is conducted at centres with trained technicians and calibrated equipment.

Who should get tested and when?

There’s no universal rule for screening, but Dr Nair says testing is helpful if:

• Those exposed to heavy traffic or indoor smoke
• Those with childhood lung issues
• Individuals with a family history of respiratory disease

People in high-risk jobs, like traffic police, factory workers, or construction staff, should undergo periodic spirometry every 1–2 years.

 

For smokers or those with early disease, frequency should be personalised. “We test at the first sign of symptoms and then repeat based on the individual’s progress or exposure,” he adds.

Can your lungs recover after quitting smoking or reducing exposure?

Much of the damage can be stabilised or even partially reversed if caught early.

 

“Asthma-type obstruction often improves with medication. COPD is only partially reversible, but quitting smoking slows its progression,” says Dr Nair.

 

He recommends reducing exposure, regular exercise, proper nutrition, vaccination, and inhaled bronchodilators for the best outcomes. Air purifiers and masks can help reduce exposure, he adds, “but they’re aids, not substitutes for clean air and smoking cessation.”

Why ignoring a persistent cough is risky

Ignoring a lingering cough won’t make it go away, rather it hides a worsening condition.

 

“In asthma or COPD, untreated inflammation leads to airway remodelling and permanent damage,” warns Dr Nair. “In smokers, it can delay detection of early lung cancer, where treatment is most effective.”

 

A timely lung function test could mean the difference between early control and late-stage crisis. 

When to stop waiting it out and see a doctor

Doctors say you should see a physician if you notice any of the following:

• A cough lasting more than eight weeks
• Shortness of breath
• Wheezing or chest tightness 
• Coughing up blood
• Recurrent chest infections or fevers
• Unexplained weight loss or fatigue
• Frequent exposure to pollution, dust, or smoke

"Many people wait too long, assuming a nagging cough will resolve on its own, especially during pollution season. But, don’t dismiss a cough that lingers beyond eight weeks, or breathlessness that limits your daily activity,” stresses Dr Nair. “Also, if you’re coughing up blood, wheezing, feeling chest tightness, or noticing unintentional weight loss, consult a physician immediately.” 

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