Once: Mostly once depending on your profession and exposure at work. If you work in an office setting, or mostly indoors and not in industrial areas, once a day should suffice.
Answered 3/6/2013
5.3k views
A doctor has provided 1 answer
A doctor has provided 1 answer
A doctor has provided 1 answer
3 doctors weighed in across 2 answers
90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more.
Ask your question