Atmospheric Pollution

Photochemical smog contains:
Ozone, nitric oxide, organic compounds, nitrogen dioxide, formaldehyde.
∴ SO₂ is not the part of photochemical smog.

Statement A is correct. Ammonium salts, such as ammonium sulfate and ammonium nitrate, can contribute to atmospheric haze. These salts can form fine particulate matter in the atmosphere, which scatters light and reduces visibility, leading to haze. This phenomenon is often associated with agricultural emissions and industrial pollution.

Statement B is incorrect. Ozone is primarily formed by the reaction of sunlight with oxygen molecules ( ) and various pollutants like nitrogen oxides ( ) and volatile organic compounds (VOCs). While chlorine radicals can destroy ozone, they do not directly contribute to its formation.

Statement C is correct. Polychlorinated biphenyls (PCBs) are indeed industrial chemicals, but they were historically used in various products, including as coolants and lubricants in electrical equipment. They are persistent environmental pollutants and are harmful to both human health and the environment. Although not cleaning solvents, they were widely used in industrial applications.

Statement D is incorrect. 'Blue baby' syndrome is caused by excess nitrate ions in drinking water, which can interfere with the ability of red blood cells to carry oxygen, leading to methemoglobinemia. This condition causes a bluish tint to the skin, particularly in infants. Sulfate ions are not responsible for this condition.