Correct Answer: Option A) 1 and 3 only
Synergism in environmental pollution refers to the interaction between two or more pollutants that produces a combined effect greater than the sum of their separate effects. Let's analyze each statement:
It refers to the combined effect of primary pollutants creating more toxic substances - TRUE. Synergism occurs when primary pollutants interact in the atmosphere to form secondary pollutants that are often more toxic than the original substances. This is a correct definition of synergism in the context of pollution.
It always leads to less harmful by-products - FALSE. This statement is incorrect. Synergism typically leads to more harmful compounds, not less harmful ones. The whole concern with synergistic effects is that they often create substances that are more dangerous than the original pollutants.
PAN and smog are examples of products formed via synergism - TRUE. Peroxyacetyl nitrate (PAN) is formed through photochemical reactions involving nitrogen oxides and volatile organic compounds. Similarly, photochemical smog is created when primary pollutants (like nitrogen oxides and hydrocarbons) interact with sunlight to form secondary pollutants. Both are classic examples of synergistic effects in environmental pollution.
