The easiest way to reduce your exposure to dangerous fumes is to keep your head out of a fume plume, making sure that you're breathing the cleanest air possible.

keep your head out of a fume plume

Explanation:

According to the guidelines and precaution procedures of OSHA, an acronym for Occupational Safety and Health Administration in the United States of America stated that The easiest way for an individual to reduce his or her exposure to dangerous fumes is to ensure that such person keeps his or her head out of a fume plume.

Hence, in this situation, the correct answer is "keep your head out of a fume plume"