What is smog? How is classical smog different from photochemical smogs?

Explanation

### Step-by-Step Solution

**Step 1: Definition of Smog**
Smog is a type of intense air pollution that is visible and primarily composed of various air pollutants. It is often described as a combination of smoke and fog, leading to reduced visibility and harmful effects on health and the environment.

**Step 2: Composition of Smog**
Smog is mainly composed of oxides of sulfur (SOx), nitrogen (NOx), smoke, ozone (O3), and other particulates. These components can originate from various sources, including industrial emissions, automobile emissions, forest fires, and the combustion of coal and other fossil fuels.

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