What are the health effects of breathing smog?

In one line

The rule

Smog is a type of air pollution made of smoke, dust, and harmful gases that can cause health problems when breathed in.

Let's understand it simply

Imagine you are walking on a busy road in Delhi during winter. The air looks foggy, but it smells bad and makes your eyes burn. This is smog (smoke + fog). When you breathe in smog, tiny harmful things go into your lungs. It is like trying to breathe in a kitchen full of burning chillies — your chest hurts, your eyes water, and you start coughing. Smog is not just dirty air; it has chemicals and dust that your body does not like.

How it works

1. Smog forms when smoke from vehicles, factories, and burning waste mixes with fog or moisture in the air.
2. The air fills with tiny particles (called particulate matter) and gases like ozone, nitrogen dioxide, and sulphur dioxide.
3. When you breathe, these particles and gases enter your nose, throat, and lungs.
4. The body tries to block them, but some get deep into your lungs and even your blood.
5. These substances can irritate your airways, cause swelling, and make it hard for you to breathe.
6. Over time, breathing smog can damage your lungs, heart, and even affect your brain.

The story behind it

The word "smog" was first used in London in the early 1900s, when thick smoke from burning coal mixed with fog and made the air dangerous. In 1952, the "Great Smog of London" killed thousands of people in just a few days. This disaster made governments realise how dangerous air pollution can be for health. Today, cities like Delhi, Beijing, and Los Angeles still face smog problems, especially in winter.

Where you see it in real life

• Delhi winters: After Diwali, fireworks and crop burning create thick smog. Many people cough, get sore throats, or need to wear masks.
• Traffic jams: Stuck behind a diesel truck, you breathe in black smoke, which is a big part of smog.
• Factories: Areas near factories often have more smog, and people there get more breathing problems.
• Burning garbage: In some towns, burning plastic and waste adds to smog, making the air smell bad and unsafe.
• School sports: When air is very polluted, outdoor games are cancelled because smog makes it unsafe to run or play.
• Crowded bus stops: Breathing in the smoke from many vehicles at once can make your eyes water and chest tight.

Why it matters

• Health: Smog can cause asthma attacks, cough, chest pain, and even lung cancer if you breathe it for years.
• Children and old people: They get sick more easily from smog because their lungs are weaker.
• Missed school or work: Bad smog days mean people stay home, miss classes, or cannot go to the market.
• Hospitals get crowded: More people visit doctors for breathing problems during smoggy days.

Worked example

Let's see how smog affects a 12-year-old student:

Given: Student has to walk 2 km to school during heavy smog.
Step 1: Student breathes in air with high particulate matter (PM2.5).
Step 2: PM2.5 enters lungs, irritates airways.
Step 3: Student starts coughing, feels chest tightness.
Step 4: If student has asthma, may get an asthma attack.
Step 5: Student needs to rest or use an inhaler, may miss school.

Common mistakes

• Thinking smog is just fog: Fog is only water droplets; smog has harmful chemicals and dust.
• Believing only factories cause smog: Vehicles, burning waste, and even fireworks add to smog.
• Assuming masks are useless: Good masks (N95) can help block some harmful particles.
• Ignoring smog indoors: Smog can enter homes, so closing windows and using air purifiers helps.

Remember it

Smog = smoke + fog. If the air looks dirty and smells bad, it can harm your lungs — cover your nose, avoid outdoor activity, and stay safe.