Question

The photochemical smog does not generally contain:

• A. NO
• B. SO\(_2\)
• C. NO\(_2\)
• D. HCHO

Hint:

Photochemical smog forms in the presence of sunlight, NO\(_x\), and VOCs. Industrial smog, on the other hand, is associated with SO\(_2\) and particulate matter.

Answer 1

The Correct Option is B

Photochemical smog is a type of air pollution that primarily consists of nitrogen oxides (NO\(_x\)) and volatile organic compounds (VOCs) that react under the influence of sunlight to form secondary pollutants, including ozone (O\(_3\)), formaldehyde (HCHO), and peroxyacetyl nitrates (PANs). Step 1: In the formation of photochemical smog, nitrogen oxides like NO and NO\(_2\) play a crucial role, along with VOCs. These pollutants lead to the formation of ozone and other harmful compounds. 
Step 2: SO\(_2\) (sulfur dioxide) is typically associated with industrial smog (or ``London-type smog"), which is different from photochemical smog. 
It does not generally participate in the formation of photochemical smog under normal sunlight conditions. 
Step 3: Therefore, SO\(_2\) is not generally present in photochemical smog, unlike NO, NO\(_2\), and HCHO, which are key components.