You want to protect your lungs from fine wood dust in the shop, but wearing a mask fogs up your glasses.
Choose filter masks that feature an exhalation valve. These masks allow the warm, moist exhalation from your breath to escape instead of creeping under the upper edge of the mask and fogging your safety and/or prescription glasses. Disposable masks with exhalation valves are affordable and comfortable to wear. To get the best lung protection, as well as prevent fogging, press the disposable mask’s nosepiece down so that it conforms closely to the contour of your nose and cheekbone. Alternately, choose a rubber half-mask respirator that uses replaceable filter elements. For the best fit with a half mask, choose the size (small, medium, large) that fits your face best.