OSHA regulates respirators use. The simple fact is you would have a hard time sourcing them. Fit testing, proper use and now reuse would be difficult for someone with zero training. Now 100% use of disposable surgical or reusable homemade masks would be helpful. What you can do without any ppe is wash your hands and don't touch your face. A virus will not enter through your hands, but your hands are great vehicle's to your eyes, nose, mouth. Any type of work gloves can help you remember not to touch and protect your hands from repeated washing. Just don't believe gloves offer any protection or assume your hands are clean underneath.