"N100 and P100 Masks for Protection against Avian Flu, Swine Flu and Other Diseases
The Centers for Disease Control tested N100 and P100 masks for their efficacy against avian flu, swine flu and other contagious diseases and found them to provide superior protection.
Since N100 respirators and P100 respirators are capable of blocking the majority of airborne hazards, people often use them to prevent the spread of dangerous diseases." [1]
N95 masks are useful for preventing sick people from spreading disease by coughing. They are only really usable once. The media is promoting surgical masks which are only designed to prevent a surgeon from contaminating the operating table with droplets from her mouth(the literature mentions HCP to HCP prevention which is a sick doctor from infecting a colleague); these masks do NOT provide enough protection to prevent inhaling a virus. You will need HEPA which you will get with a N100 / P100 mask that has a carbon filter. No one is talking about N100 / P100 because they are only rated for trained individuals and occupational use.
In a environment where you will be exposed to the virus, you must also cover your eyes. Virus can infect you through mucus membranes. At least get a tight fitting goggles, or a full face shield. Glasses with side sheilds will be better than nothing, but why take the chance.
The proper gear has an indefinite shelf life. Expect that there will be waves if this becomes a full pandemic. Some estimates that this could be three month cycles. The R0 factor means more people infected by pre-symptomatic carriers. The beginning and middle of the cycle will have the most cases. The end of the cycle will be cleaning up and trying to get back to normal.
Get plenty of disinfectant or chlorine based cleaners. You will want to clean all items you take outdoors. Wash your hands, wear gloves, wash the gloves. Overcoats / pants can be warn, and these are left outdoors, and or cleaned or washed outside.
See also diagram on donning sequences. [2]
[1] https://www.envirosafetyproducts.com/respirators-safety-prot...
[2] https://www.cdc.gov/HAI/pdfs/ppe/ppeposter1322.pdf