It might be hard to control what you run across out in public, such as the air you breath and the people you meet and interact with. But in your own home you can easily put a few things into place that will help you prevent spreading cold and flu types of illnesses to other family members.
UV-enabled air purifiers have the ability to kill the stuff that causes the common cold and the flu. HEPA air purifiers can filter particles down to .3 micrometers in size, but the size of the particles that spread these viruses can be even smaller than that. To effectively clean the air of virus-spreading particles and germs, you need to maybe look at using UV.
Many people have central air systems in their homes already. If you do, you can likely get a UV purifier installed into your system, and use it to filter your air house-wide.
If you don’t have a system like this in place, or can’t afford the cost that goes along with central systems, you can also look at getting an air purifier that includes UV features along with a HEPA filter. Many home units have just that.
Units such as the Alen Peralda have UV in addition to HEPA filters, and can filter out many types of virus-related particles due to this.
Even if you aren’t particularly concerned about cold and flu season, you can also rely on UV purifiers to help filter out stuff like mold, spores and stuff that causes allergies and skin irritations. It can overall be a very good investment.