GEOLOGY

Detailed explanation-1: -The correct option is O3. O3 is the chemical formula of ozone gas. It is not a primary pollutant. It is a secondary pollutant.

Detailed explanation-2: -Ground-level ozone is a colorless and highly irritating gas that forms just above the earth’s surface. It is called a “secondary” pollutant because it is produced when two primary pollutants react in sunlight and stagnant air. These two primary pollutants are nitrogen oxides (NOx) and volatile organic compounds (VOCs).

Detailed explanation-3: -Types of primary pollutants include: Nitrogen oxides (NOx) Carbon monoxide (CO) Volatile organic compounds (VOCs)

Detailed explanation-4: -Tropospheric or ground-level ozone – what we breathe – is formed primarily from photochemical reactions between two major classes of air pollutants, volatile organic compounds (VOC) and nitrogen oxides (NOx).

Detailed explanation-5: -b) ozone; Ozone is NOT a primary pollutant. Primary pollutants are pollutants emitted into the atmosphere directly from the source (by human activity), from the combustion of fossil fuels. They include carbon monoxide, particulate matter, volatile organic compounds (VOCs), nitrogen oxides, and sulfur oxides.