Economic measures are directed at those who cause environmental costs.

directed 是动词 direct 的过去分词形式，direct 的意思是"指向、针对"，这里表示"被引导、被指向"。 at 是介词，表示"在...方向/目标"，在这里与 directed 搭配表示"针对某个对象"。 directed at 这个短语表示"针对...的、指向...的"，强调措施的目标对象。