Discuss : Synergism.

Explanation

Synergism. Pollutants formed by reaction among the primary pollutants called as secondary pollutants are often more harmful than primary pollutants. So the combined action of several chemicals which produce, a total effect greater than the effect of primary chemicals separately as called is synergism. e.g., PAN-Peracyl nitrates are the secondary pollutants formed through reaction between oxides of nitrogen and hydrocarbons in presence of sunlight.