The document discusses various types of air pollution including sulfur dioxide (SO2). It notes that SO2 is produced by volcanoes and industrial processes involving coal and petroleum. The burning of these fossil fuels that contain sulfur compounds generates SO2. It is a colorless gas that has significant health and environmental effects such as acid rain formation and impacting human health by burning lung tissues upon inhalation. Chronic exposure to high SO2 levels can cause respiratory illnesses like asthma and bronchitis as well as heart disease, especially in vulnerable groups like children.