Orchid leaves will turn yellow as the plant ages, however yellowing of new leaves is a symptom of disease and can be caused by too much light, sudden environmental changes, over or under watering or not enough nutrients in the soil. Fumes from paint and cleaning supplies change the quality of the air adding pollutants that the orchid cannot process. Cold drafts lower the temperature surrounding the orchid too quickly causing the orchid to go into shock. You will need determine the cause of the problem in order to remedy the situation.
Move the orchid to a location that is out of direct sunlight. Orchids need 10 to 15 hours of filtered sunlight per day.
Water the orchid if the soil is completely dry. Remove excess water and do not water for one to two weeks. After one to two weeks water orchids only once per week.
Add orchid fertilizer to the soil (per package directions) if the leaves remain yellow one week after eliminating other causes of yellowing leaves.
Apply a fungicide or bactericide to the orchid plant to remove infections. Yellow spots with black centers on the leaves is an indication of fungal or bacterial infection.
Move orchids to another room temporarily while painting. Use cleaning supplies that do not give off heavy fumes when cleaning near orchids, such as non-aerosol cleaners that do not contain bleach or ammonia. Place a window fan in the window so that it is pulling air out of a room (use the exhaust setting if it has one) to increase circulation and remove heavy fumes.