Ethics of trading with China

I know that conditions for some workers in China are appalling. How can we really know if we are sourcing products from sweatshops or other exploitive setups?
China also has some major ecological issues; horrendous pollution, water crises and fast advancing deserts.
How can our trade with China be mutually beneficial without contributing to the rapid demise of the planet?
Are there some regulatory bodies we can check with?
I'm interested to know what others think about this.
I want to be able to trade with a clear conscience.

Hmm, Im not sure about this question. I would have to say the majority of chineese labor is practically sweatshop conditions. That is why alot of big american companys have thier items manufactured there.