Does a surgical or cloth mask protect against smog, or do I need an N95?

A cloth or surgical mask may give little protection against smog (zehreeli dhund), because polluted air leaks in around the loose edges. A well-fitted N95 respirator can reduce the fine particles you breathe in. An N95 does not filter the gases in smog, so spending less time outdoors still matters most.

What the evidence says

• Pakistan's National Institute of Health (NIH) advises wearing high-quality N95 masks outdoors during smog, cutting outdoor activity in peak smog hours, and keeping windows and doors shut.
• Health Canada's guidance on smoke says cloth, medical and surgical masks don't fit the face well and may not filter the particles. A scarf, bandana or face shield won't protect you, and even a respirator does not protect against the gases.
• Fit decides how well a mask works. A study tested nine masks sold in Beijing to protect against fine particles (PM2.5). On volunteers, the share of polluted air leaking in ranged from 3% to 68%, and only one mask type kept leakage under 10%. The researchers blamed poor fit.

How to wear an N95 properly

• Bend the metal nose strip so it sits snugly over your nose, then adjust the straps or ear loops.
• Check the seal. Air should not escape around the edges when you breathe out.
• A beard stops the mask sealing and makes it work less well.
• Replace it when it is dirty, damp or damaged.

Who needs extra care

Health Canada says children under 2 should not wear respirator masks, and nobody should keep wearing one that makes breathing difficult. People with lung or heart conditions may find masks hard to tolerate, so ask your doctor what suits you. The NIH advisory names children, older people, pregnant women and people with heart disease, diabetes or lung disease as more vulnerable. For everyone, Health Canada says the best protection is to reduce exposure, by limiting time outdoors and keeping indoor air clean. People with asthma (dama) can read our guide to asthma and inhalers.

When to see a doctor

Mild eye, nose and throat irritation (aankhon mein jalan, gala kharab), a mild cough and headaches are common in smoky air and often settle without treatment. See a general physician if you have wheezing, a severe cough, dizziness, palpitations or an asthma attack, or if any symptom persists or gets worse.

Emergency signs

Call Rescue 1122 or Edhi 115, or go to the nearest emergency department, for chest pain or severe shortness of breath (saans phoolna).

Sources

• Dawn: KP health department smog advisory prepared by NIH Islamabad (23 November 2025)
• Health Canada: Using a respirator mask during wildfire smoke events
• Health Canada: Wildfire smoke and your health
• Effectiveness of face masks used to protect Beijing residents against particulate air pollution (Occupational and Environmental Medicine, 2018)

General health information from the DoctorOS Team, not a diagnosis. For advice about your own situation, see a doctor.