Photochemical smog is formed when primary pollutants interact with __. a. sunlight b. carbon c. water vapor d. sulfur dioxide e. oxygen
The Correct Answer and Explanation is:
The correct answer is a. sunlight.
Photochemical smog is a type of air pollution that results from the interaction of primary pollutants with sunlight, particularly ultraviolet (UV) light. Primary pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs) are released into the atmosphere primarily from vehicle emissions, industrial processes, and the burning of fossil fuels.
When these pollutants are exposed to sunlight, they undergo chemical reactions that produce secondary pollutants, including ground-level ozone (O₃) and other reactive compounds. These secondary pollutants are harmful to human health and the environment. The combination of sunlight and pollutants creates a smoggy haze that is often seen in urban areas, especially during hot, sunny days.
The formation of photochemical smog occurs in several stages. First, nitrogen oxides (NO and NO₂) are emitted into the air from vehicle exhaust and industrial sources. In the presence of sunlight, these nitrogen oxides react with VOCs, which can come from gasoline vapors, solvents, and even natural sources like plants. This reaction leads to the formation of ozone and other compounds like peroxyacetyl nitrates (PANs), which contribute to the overall smog formation.
Photochemical smog is more common in cities with high levels of vehicle traffic and industrial activity, where the sunlight can trigger these chemical reactions. It can have severe health consequences, including respiratory problems, eye irritation, and exacerbation of asthma. Additionally, it can damage crops and forests, reduce visibility, and contribute to climate change by increasing the concentration of greenhouse gases.
Thus, sunlight plays a crucial role in the formation of photochemical smog, driving the chemical reactions that create harmful secondary pollutants.
