Once upon a time, interior design was concerned only with aesthetics. That is, the subjective aspects of beauty, how something looks to the observor. Ethics, that is, whether or not something is good for you, or has any morality to it, had absolutely no place in the worldview of interior design.
In the last few decades, an interesting shift has taken place. A new interest has seized hold of the public imagination. This interest has as much to do with whether or not something is good, healthy and sustainable for the end user, as to whether or not it is aesthetically pleasing. Consequently, this new paradigm has given birth to an entirely new field of design, sometimes called, "Sustainable Design", that seeks to merge aesthetics + ethics.
Another, easier approach that some design schools are taking is to call this new zeitgeist Environmentally Responsible Interior Design (ERID). An ERID approach simply involves making intelligent, thoughtful interior design choices that involve sustainable materials. For example, a designer could suggest that a client use Bamboo floors (made from sustainable and renewable bamboo), low VOC paints, or other products manufactured in plants that keep a low Carbon footprint. Such choices can have a meaningful impact on the environment as a whole.