The question is based on the hypothesis that the 100 billion USA dollars trade war will happen between China and USA and it will last for years (say at least three years).
The manufacturing industry in China may shrink or be relocated to USA or other developed/developing countries? It will make the pollution in China less serious but the pollution could be also relocated.
This is a most worrisome international quagmire. Millions or billions of dollars will go into the waters. Beijing and Washington need each other. President Trump just want tax returns on China's trade investments and investment relationships with the US.
Sincerely, they will sought it out and America shall benefits the more.
Should this war on trade continues, the Third World shall be at the receiving end.
I wish them the best. As am hopeful that the indifferent shall be over soon.