Final answer:
Secondary pollutants are formed when primary pollutants interact with sunlight, air, or each other. Ozone is an example of a secondary pollutant that is formed when pollutants interact with sunlight.
Step-by-step explanation:
Secondary pollutants are formed when primary pollutants interact with sunlight, air, or each other. They do not directly cause pollution. However, when they interact with other parts of the air, they do cause pollution. For example, ozone is created when some pollutants interact with sunlight. High levels of ozone in the atmosphere can cause problems for humans.