The right kind of mask, with a proper fit, can help protect your lungs from wildfire smoke.
Paper masks with one strap and surgical masks will NOT protect your lungs from wildfire smoke.
A "particulate respirator" mask is much more effective at removing small airborne particles such as those from a fire. The mask should have the word NIOSH and either "N95" or "P100" printed on it. You can find these masks at many hardware and home repair stores and at pharmacies. Be sure to follow the manufacturer's instructions carefully.
For more details, please see this document from the California Air Resources Board:
http://www.arb.ca.gov/carpa/toolkit/data-to-mes/wildfire-smoke-guide.pdf (pages 17 to 21 and Appendix B)