I am sure the sulphur dioxide in Wuhan comes from industry pollution. Everything you can think of is being made in and around Wuhan and lots of it produces toxic emissions. That's why they moved the manufacturing from the USA to Wuhan (actually all over China). It makes everybody feel good when they don't pollute in the USA and fuck China, its 8000 miles away. They say they moved production to China because it is cheaper to produce. Hell yes it is cheaper, there are no environmental regulations.