Which of the following is not a primary air pollutant?

Correct option is C

O₃ (Ozone) is not a primary air pollutant; it is a secondary air pollutant. Primary pollutants are directly emitted from a source, such as CO (carbon monoxide), NO (nitric oxide), and SO₂ (sulfur dioxide), which are released into the atmosphere from activities like combustion and industrial processes. In contrast, ozone (O₃) forms in the atmosphere through chemical reactions between primary pollutants like nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight, making it a secondary pollutant.
Information booster:
1. Primary pollutants are directly emitted into the air from sources such as vehicles, factories, and natural processes like volcanic eruptions.
2. Secondary pollutants are formed in the atmosphere through chemical reactions involving primary pollutants.
3. Ozone (O₃), while protective in the stratosphere, is a harmful air pollutant at ground level, contributing to smog.
Additional Knowledge:
· CO (carbon monoxide) is a primary pollutant emitted from vehicle exhaust and incomplete combustion processes.
· NO (nitric oxide) and SO₂ (sulfur dioxide) are also primary pollutants produced by fossil fuel combustion, with significant impacts on air quality and human health.