PPEs, or personal protective equipment, is a topic that is hardly ever covered by survivalists but it is pretty important when it comes to protecting yourself from everything from viruses to lung infections.
What they are: Personal protective equipment can range from the hearing and eye protection you wear at the shooting range to the gloves that healthcare workers use to the hard hats and respirators that are used in the construction industry. The personal protective equipment you choose has much to do with the types of situations you may find yourself in. Basically you want to use PPE gears to protect yourself from anything that could cause you harm (this could range from loud noise when shooting to preventing contamination during a disease outbreak). The basic PPEs that everyone should have on hand include rubber gloves, dust masks, N95 masks if possible, goggles, life jackets, hearing protection (ear plugs as well as shooting ear muffs), leather gloves, and high visibility safety vests.
Where to buy them: Most of these are common items which can be found quite cheaply at Walmart and Home Depot. For more specialized gear (like Tyvek coveralls) you can easily find these items online.
When to use them: Many people don't give much thought to using PPEs unless they work in healthcare, construction, or other fields where such items are required by OSHA. However, everyone should use PPEs when they find themselves in situations where they could be harmed or contaminated. When shooting, eye and ear protection should always be used. When boating a life jacket should always be worn. When cleaning up after a disaster, gloves and masks are a minimum of what should be worn to prevent contamination and infection. When painting or doing major contaminant clean up, coveralls, gloves, goggles, and a respirator can save your health and in some cases your life. Should there be a major disease outbreak (a la ebola) complete PPEs should be warn when taking care of the sick.
So along with your preps and stockpiles, be sure to keep some personal protective equipment on hand for use during a disaster (and for use in everyday life when needed).