The term "open to the air" refers to something that is exposed to the elements or the outside environment. There are many synonyms that can be used to describe this concept, including "outdoor," "uncovered," "exposed," "unprotected," and "unsheltered." Other synonyms may include terms like "ventilated," "airy," "breathable," and "fresh." All of these words convey the idea of something being open or accessible to the surrounding air and environment. Whether describing a building, a space, or an object, using synonyms for "open to the air" can add detail and nuance to your writing or conversation.