2. Use your air conditioner
Speaking of ventilation, ACs can also help in this regard, as they not only bring in fresh air from outside but have filters that can reduce airborne contaminants, including some viruses, indoors. Do note that having your AC on doesn’t prevent Covid-19 from spreading or eliminate the virus from the air. Nevertheless, it does help with the generally good practice of increasing ventilation, and every extra step taken to remove the potential presence of the virus helps.
If you happen to have a full, house-wide HVAC system, you could improve your home’s ventilation by running the system fan for longer times since the AC only filters the air when the fan is on. This can be done even without heating or cooling.
For either a full HVAC system or a series of individual ACs, check that the filters are set properly and are regularly changed (or changed once they become exceptionally dirty) to make sure your ACs effectively filter the air.