The correct answer is: A. Ammonia
Ammonia is a secondary pollutant, while the other options are primary pollutants.
- Primary pollutants are emitted directly into the air from a variety of sources, including vehicles, power plants, and industrial facilities.
- Secondary pollutants are formed when primary pollutants react with other chemicals in the atmosphere.
Ammonia is a colorless gas with a strong odor. It is produced naturally by the decomposition of organic matter and by the action of bacteria on nitrogenous compounds. Ammonia is also used in a variety of industrial processes, including the production of fertilizers, plastics, and explosives.
When ammonia is released into the atmosphere, it can react with other pollutants to form secondary pollutants, such as ammonium nitrate and ammonium sulfate. These pollutants can contribute to acid rain and smog.
Sulfur dioxide is a colorless gas with a strong, irritating odor. It is produced when sulfur-containing fuels, such as coal and oil, are burned. Sulfur dioxide is also released from volcanoes and other natural sources.
Sulfur dioxide can react with water vapor in the atmosphere to form sulfuric acid, which is a major component of acid rain. Sulfur dioxide can also cause respiratory problems in humans and other animals.
Hydrogen sulfide is a colorless gas with a rotten egg odor. It is produced by the decomposition of organic matter and by the action of bacteria on sulfur-containing compounds. Hydrogen sulfide is also used in a variety of industrial processes, including the production of sulfuric acid and fertilizers.
When hydrogen sulfide is released into the atmosphere, it can react with other pollutants to form secondary pollutants, such as sulfuric acid and sulfurous acid. These pollutants can contribute to acid rain and smog.
Peroxyacetyl nitrate (PAN) is a colorless, oily liquid that is formed when nitrogen oxides and volatile organic compounds react in the presence of sunlight. PAN is a major component of photochemical smog.
PAN can cause a variety of health problems, including eye irritation, respiratory problems, and damage to the nervous system. It can also damage plants and crops.