Air pollution is a major environmental issue that affects the health of people and ecosystems. Two of the most common air pollutants are SMOG and SOOT. SMOG is a combination of smoke and fog, created when sunlight reacts with pollutants in the air. SOOT is a black or dark-colored solid material made up of tiny particles that are released into the air from burning fossil fuels. Both SMOG and SOOT can have serious health effects, including respiratory problems, heart disease, and cancer.