What type of air pollution is primarily linked to vehicle emissions?

Ground-level ozone is a significant concern related to vehicle emissions, primarily due to the chemical reactions that occur in the atmosphere. When vehicles release nitrogen oxides (NOx) and volatile organic compounds (VOCs) as byproducts of fuel combustion, these pollutants can react with sunlight and heat to form ground-level ozone. This type of air pollution is especially prevalent in urban areas with heavy traffic, where the conditions for ozone formation are often present. High concentrations of ground-level ozone can lead to respiratory problems and other health issues, making it a critical factor in air quality management associated with vehicular emissions.

The other options represent different types of air pollutants. Particulate matter can originate from various sources, including vehicle emissions, but is not exclusively linked to them. Sulfur dioxide primarily comes from burning fossil fuels, such as coal, and is not directly associated with vehicle emissions. Carbon monoxide is another pollutant emitted by vehicles, but ground-level ozone is the main byproduct involved in the specific chemical processes linked to vehicular emissions and sunlight interaction. Thus, the focus on ground-level ozone highlights the unique nature of its formation in connection with vehicle-related pollution.