PA Emissions Inspector Certification Exam 2026 – Complete Practice Test

The correct answer highlights three key components necessary for the formation of smog: ozone, nitrogen oxides, and sunlight.

In the context of smog, particularly in urban areas, ozone is a significant component of photochemical smog, which forms when sunlight initiates chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) produced by vehicle emissions and industrial processes. The presence of sunlight is crucial because it provides the energy needed for these chemical reactions to occur. Nitrogen oxides, which are generated from combustion processes, play a critical role in creating ground-level ozone when combined with sunlight.

Understanding these components helps illustrate the complex interplay between pollutants and environmental conditions that contribute to smog formation. The other options do not correctly specify the components that lead to smog formation, making them less relevant in this context.