Ozone, option 2, is the correct answer. Particulate pollutants refer to tiny solid or liquid particles suspended in the air. They can be emitted directly from sources such as dust, soot, or smoke. However, ozone is not a particulate pollutant. Ozone is a gas that is formed when sunlight interacts with pollutants like nitrogen oxides and volatile organic compounds. It is a major component of smog and can have harmful effects on human health and the environment. While ozone is a harmful air pollutant, it is not considered a particulate pollutant because it exists in the form of a gas rather than solid or liquid particles.