No-It is a myth that fingernails must be exposed to fresh air to stay healthy, according so some dermatologists.  In fact 24-7 polish protects weak nails from breaking.  To prevent nails from yellowing, it is advised to apply a base coat before the colored polish-especially if you use dark shades.  Darker colored nail polish is more likely to cause your fingers to yellow; the yellowing is harmless and purely cosmetic.

If your nails are already yellowed, you can try rubbing them with a lemon wedge.  The acids in the lemon help to whiten the fingernail.