Respuesta :
Answer:
Tobacco smoke
Explanation:
Air pollution is the presence of particulate matter or harmful gases in the air. These include various compounds/elements like nitrogen dioxide, lead, carbon dioxide, sulfur dioxide etc. The main sources of air pollution include, automobile exhaust, chemicals from factories, coal powered plants etc.
However, indoor air pollution can be more harmful to health than outdoor pollution as it contributes towards respiratory problems. The greatest source of indoor air pollution is tobacco smoke.
