Smog and fog are two distinct atmospheric phenomena, although they can sometimes appear similar. Here are the key differences between smog and fog:
Fog is an atmospheric phenomenon that occurs naturally. It is a group of ice crystals or water droplets floating in the air close to the ground that impairs vision. Particularly during temperature inversions or when warm, humid air passes over a cooler surface, fog is created when moist air cools and condenses.
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When smoke and fog combine, a form of air pollution known as smog is created. Pollutants like sulphur dioxide, nitrogen oxides, and particulate matter are frequently found in it. Urban locations with significant amounts of industrial and transportation emissions are usually the sites of smog.
Smoke + Fog = Smog
| Characteristics | Smog | Fog |
| Definition | A type of air pollution resulting from a mixture of smoke, pollutants (like nitrogen oxides and volatile organic compounds), and fog. | A natural phenomenon consisting of tiny water droplets suspended in the air, reducing visibility. It typically occurs in cool, humid conditions. |
| Formation | It forms when sunlight reacts with these pollutants creating a thick, often harmful haze. | During condensation molecules of water vapour combines to make tiny water droplets that hang in the air. |
| Causes | Primary caused by human activities, such as burning of the fossil fuels, industrial processes, and vehicular emissions. | Formed by natural atmospheric processes, usually as a result of cooling air, often during the night. |
| Visibility | Smog can reduce visibility; it is more associated with a hazy appearance due to the presence of the pollutants. | Fog significantly reduces visibility, often to a few hundred meters or less. |
| Location | Typically found in industrial areas with high levels of pollution. | Occur in various environments, including rural areas, valleys and coastal regions and is not necessarily linked to pollution. |
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Causes of smoke and its effect on Human Health:
- Vehicle Emissions: Combustion engines release nitrogen oxides and hydrocarbons.
- Industrial Activities: Factories emit large quantities of pollutants, including sulphur dioxide and carbon monoxide.
- Burning Fossil Fuels: Coal and petroleum combustion release particulate matter and harmful gases.
- Agriculture Practices: Stubble burning contributes to particulate matter in the atmosphere.
- Natural Factors: Volcanic eruptions or wildfires can release pollutants contributing to smog.
Effect of Smog on Human Health:
- Respiratory Issues: Increases the risk of asthma, bronchitis, and other lung diseases.
- Eye Irritation: Causes burning or watery eyes.
- Heart Problems: Long-term exposure can lead to cardiovascular diseases.
- Reduced Immunity: Makes the body more susceptible to infections.
- Lung Damage: Prolonged exposure can result in permanent damage to the lungs.
Latest technologies to eliminate smog to avoid atmospheric pollution:
Smog towers are large-scale air purification structures designed to reduce particulate in the air.
How It Works:
- The tower sucks in polluted air through multiple fans at the base.
- The air passage through high-efficiency particulate air filters, which trap harmful particles like PM2.5 and PM10.
- The clean air is released back into the atmosphere through vents at the top.