Using a mask alone with no one around defeats the purpose for it’s use.
It will do absolutely nothing for you.
A mask is designed for close contact with other humans from droplets of the virus.
Not the air we breathe outside.
The COVID-19 virus does not fly around like a bird outside. It is only transmitted through human contact as in touching, sneezing or coughing when someone is infected.
The best practice is to wash your hands frequently and never touch your face if you can avoid it.