Natural and industrial sources of sulfur dioxide and oxides of nitrogen

SO2 emissions

  • $2/3$ from volcanoes
  • $1/3$ from industries [eg electricity generation, metal manufacturing, metal ore mining]

NOx emissions

  • Biological cycling of nitrogen [nitric oxide, nitrous oxide], thermal processes in the atmosphere from lightnings/bushfires
  • Motor vehicle emissions/smog,electricity supply, mining, oil and gas extraction, manufacturing industries and petroleum manufacturing.