1. Fog 🌁
- Fog is a thick cloud of tiny water droplets near the ground that reduces visibility below 1 km.
- It forms when air near the surface cools down, causing water vapor to condense.
Types of Fog
| Type | Formation Process | Example |
|---|---|---|
| Radiation Fog 🌄 | Forms on calm, clear nights as the ground loses heat rapidly. | Common in plains of North India in winter. |
| Advection Fog 🌊 | Forms when warm, moist air moves over a cold surface. | Coastal areas (San Francisco, Mumbai). |
| Valley Fog ⛰️ | Forms in low-lying areas as cold air gets trapped. | Kashmir, Himalayan valleys. |
| Frontal Fog 🌦️ | Forms when warm air meets cold air, leading to condensation. | Common before rainfall. |
✅ Impact of Fog:
- Reduces visibility, causing accidents.
- Disrupts flights and trains.
- Increases respiratory issues in polluted areas.
2. Mist 🌫️
- Mist is similar to fog but with higher visibility (above 1 km).
- Forms when humidity is high, but condensation is not dense.
- Found in early mornings, near lakes, rivers, and forests.
- Common in: Hill stations like Munnar, Darjeeling, and Ooty.
📌 Difference between Fog & Mist:
✔ Fog = Denser, visibility < 1 km.
✔ Mist = Lighter, visibility > 1 km.
3. Haze 🌁
- Haze is a layer of fine dry particles (dust, smoke, or pollution) suspended in the air.
- It reduces clarity but does not form droplets like fog.
- Common in: Industrial areas and during summers.
✅ Causes of Haze:
- Dust storms (Thar Desert, Middle East).
- Air pollution (Delhi, Beijing).
- Forest fires and volcanic eruptions.
📌 Difference between Haze & Fog:
✔ Haze = Dry particles (dust, smoke).
✔ Fog = Tiny water droplets (moisture).
4. Smog (Smoke + Fog) 🌆
- Smog is a toxic mix of fog and air pollution (smoke, dust, chemicals).
- It is harmful to health, causing respiratory diseases.
Types of Smog
| Type | Cause | Effects | Example |
|---|---|---|---|
| Industrial Smog 🏭 | Smoke from coal & industries mixes with fog. | Breathing problems, acid rain. | London (1952 Great Smog). |
| Photochemical Smog ☀️ | Sunlight reacts with vehicle emissions (NO₂, CO, O₃). | Eye irritation, breathing issues. | Delhi, Los Angeles. |
✅ Impact of Smog:
- Causes asthma, lung diseases, and heart problems.
- Reduces visibility, affecting transport.
- Damages crops and buildings.
📌 Difference between Smog & Fog:
✔ Fog = Natural phenomenon (moisture-based).
✔ Smog = Human-caused pollution (harmful chemicals).
Comparison Table: Fog, Mist, Haze, and Smog
| Feature | Fog 🌁 | Mist 🌫️ | Haze 🌫️ | Smog 🌆 |
|---|---|---|---|---|
| Composition | Water droplets | Water droplets | Dust, smoke | Smoke + Pollution |
| Visibility | <1 km | 1-2 km | Reduced but clear | Very low |
| Formation Cause | Cooling & condensation | Light condensation | Dry particles in the air | Pollution + Fog |
| Effect on Health | Mild | Mild | Irritation | Severe health risks |
| Common in | Winters, valleys | Rainforests, coastal areas | Industrial zones, deserts | Big cities (Delhi, Beijing) |
MCQs on Fog, Mist, Haze, and Smog
1. What is the main difference between fog and mist?
a) Mist is thicker than fog
b) Fog has lower visibility than mist
c) Mist occurs only at night
d) Fog occurs only in cities
Answer: b) Fog has lower visibility than mist
2. What causes industrial smog?
a) Vehicle emissions
b) Sunlight reacting with gases
c) Smoke from burning coal & factories
d) Dust storms
Answer: c) Smoke from burning coal & factories
3. Which atmospheric condition reduces visibility but is caused by dust and dry particles?
a) Fog
b) Mist
c) Haze
d) Smog
Answer: c) Haze
4. What is the main component of photochemical smog?
a) Carbon monoxide
b) Nitrogen dioxide & ozone
c) Water vapor
d) Sulfur dioxide
Answer: b) Nitrogen dioxide & ozone
5. Where is advection fog most common?
a) Deserts
b) Coastal regions
c) Mountains
d) Industrial cities
Answer: b) Coastal regions
Short Answer Questions
1. What is fog?
Fog is a thick cloud of tiny water droplets near the ground, reducing visibility to less than 1 km.
2. What is the difference between smog and fog?
- Fog is natural and made of water droplets.
- Smog is caused by pollution (smoke + fog) and is harmful.
3. What are the types of smog?
- Industrial Smog – Caused by coal burning, factories.
- Photochemical Smog – Formed when sunlight reacts with pollutants.
4. Why does fog form in winter?
- Cold air reduces temperature, causing water vapor to condense near the ground.
5. What are the effects of smog?
- Causes breathing problems, eye irritation, and heart diseases.
- Reduces visibility, affecting transportation.
Conclusion
Understanding fog, mist, haze, and smog is important for weather prediction, health, and pollution control. Competitive exams often ask questions about their differences and effects.
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