This is relatively inexpensive and does not require much planning or hardship on behalf of the teacher. Assign a student to water the plants or if students are taking medication with water have the student dump the access water into the plant. That Purify Your Home or Office by B. C. Wolverton offers an array of ways to help purify the classroom. Plants such as spider plants, fichus, and dracaena can all help reduce toxins in the classroom. Many local high schools sell plants that classes have grown in greenhouses or ask parents to donate a plant to the room.
Lighting is another area that teachers have very little control over.
Natural lighting is better than the bright fluorescent bulbs that shine in our classrooms. Some educators have no windows or very little outside light coming into the classroom therefore producing an even more of a challenge. Local fire marshals are sometimes sticklers about what is allowed in the classroom. If allowed, use lamps that are suitable for the room. Full spectrum lighting is better than the fluorescent lights that are in most classrooms.