The calculations assume that outdoor air has no virus laden particles and hence, bringing outdoor air into a room will dilute such particles, reducing risks. In addition to actual outdoor air being brought in, portable air purifiers and a good filter in your air conditioning system also help by filtering out these particles. Taking all three measures together, we present in this output a qualitative rating of the amount of effective outdoor air ventilation your room receives.
| Classification | Air changes per hour |
|---|---|
| Bad | Less than 3 |
| Low | 3 - 4 |
| Moderate | 4 - 5 |
| Good | 5 - 6 |
| Ideal | More than 6 |