High AQI Days: What Science Says About Supporting Your Lungs

Every November the same thing happens. The sky over Delhi turns grey-yellow, the AQI app goes purple, and half the office has a scratchy throat. It isn't only Delhi anymore. Lucknow, Patna, Kolkata, Mumbai and plenty of smaller cities see bad days too.

Here's what the air is doing to you, and what's worth your effort.

Why PM2.5 is the one to watch

PM2.5 means particles smaller than 2.5 microns, about thirty times thinner than a human hair. They're small enough to travel deep into the lungs, and some can pass into the bloodstream. The WHO's 2021 guideline sets an annual average limit of 5 µg/m³. On bad winter days, many Indian cities record levels far above that.

Inside the body, these particles can trigger inflammation and oxidative stress, a build-up of reactive molecules that damage cells. Over years, poor air is linked with lung disease, heart disease and stroke. In the short term you feel it as cough, irritated eyes, a tight chest, and tiredness.

Indoor air is not automatically safe

Closing the windows helps, but indoor air has its own sources: agarbatti, mosquito coils, frying, gas stoves and smoking. Outdoor PM2.5 also leaks inside.

Habits that protect you most

• Wear a proper mask outdoors. A well-fitted N95 or N99 filters fine particles. Cloth and surgical masks do much less.

• Run an air purifier with a HEPA filter in the room where you sleep, and keep that room closed.

• Time your outdoor exercise. On very high AQI days, move workouts indoors. Heavy breathing pulls more particles in.

• Cut indoor smoke. Fewer agarbattis and coils, and use the exhaust fan while cooking.

• Eat plenty of fruit and vegetables. Diets rich in antioxidants are linked with better lung function in observational studies.

Nutrients people are researching

N-acetylcysteine (NAC). NAC helps the body make glutathione, one of its main antioxidants, and it thins mucus. It is used medically for some lung conditions. Whether it helps healthy people on high-pollution days isn't well established. Doctors should guide its use, especially if you have asthma.

Sulforaphane from broccoli sprouts. Sulforaphane switches on the body's own detox pathways. In a trial in a heavily polluted region of China, a broccoli sprout drink increased how much of certain air pollutants people excreted in their urine. That's interesting, but it's one setting, and it doesn't show fewer illnesses.

Traditional respiratory herbs. Tulsi, mulethi (liquorice), vasaka (adulsa) and turmeric are used in Ayurveda for cough and breathing. Some have anti-inflammatory activity in lab studies and small trials, but strong human evidence on pollution is limited. Mulethi in large amounts can raise blood pressure.

What a supplement cannot do

No capsule or shot filters the air you breathe. Masks, purifiers and staying indoors on the worst days do far more. If you have asthma, COPD, a heart condition or a child with breathing trouble, follow your doctor's plan, and seek care quickly for breathlessness, wheezing or chest pain.

This article is for general information only and is not medical advice. Supplements are not meant to diagnose, treat, cure or prevent any disease. Speak to your doctor before starting anything new, especially if you are pregnant, breastfeeding, on medication or managing a health condition.

References

1. World Health Organization. WHO global air quality guidelines: particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. 2021.

2. Egner PA, et al. Rapid and sustainable detoxication of airborne pollutants by broccoli sprout beverage: results of a randomized clinical trial in China. Cancer Prev Res. 2014.