Is it fog or smog? This is the question that often comes to our minds, especially in winter in Delhi, when both weather phenomena coexist. Mist and fog are caused by water droplets in the air, and the only difference is how far you can see, while smog is majorly made up of ozone.
The main fog is caused by water droplets, whereas smog includes smoke and particulate matter, as per a report published by IIT Kanpur. Fog makes it hard to notice things from a distance, but isn't dangerous to health, whereas long-term exposure to smog causes chronic conditions such as asthma, or lung problems. Fog is white, whereas smog is usually darker and may change depending on specific pollutants.
The term "smog" was first coined in the early 20th century in London to describe the low-hanging pollution that covered the city. Smog burns eyes and can result in cough because it's mainly made up of ozone. When certain pollutants enter the air, like nitrogen oxides, they react with the sunlight to form ozone.
It can cause everything from eye irritation to chronic asthma and can also severely impact the productivity of agricultural areas.
Health Hazards Of Smog
- Respiratory and circulatory problems
- Asthma
- Allergies
- Nausea
- Difficulties with concentration
- Heart attacks
What Is Vog?
Vog is a specific type of air pollution that comes only from volcanic activity, the report explained. When a volcano erupts—or begins to erupt—it releases sulfur dioxide which then reacts with the other gases that are already in the air. When lava reaches the sea, it also reacts with the water to produce other chemicals like hydrogen sulfide. The resulting "fog" is called vog and can mean anything from severely reduced visibility to adding a mild, blue-grey tint to the landscape.
Delhi and other parts of north India are witnessing dense fog for the past few days. The weather department has issued a yellow alert for coldwave conditions in the national capital.