Earlier quoted context omitted.
Honestly if country A can make a product X% cheaper than country B because of having less stringent regulation (be it environmental, quality, labor laws...) it's just logical to me that country B should impose a tariff of X% on that product. I'm not much of a free-market capitalism, but if you have to be, then a free market is not a free market if not everyone is playing by the same rules, right?
That sounds sensible but the devil's in the details. How do you figure how much of X% is environmental? Do you insist the Chinese have similar pay and conditions for workers? How do you check where the rare earths you are buying in say Singapore actually came from?
Probably ideally tariff levels should not directly made by the executive, but rather some kind of review system - (although quangos are another problem).