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Summary of the intervention conditions used in the mass balance model.
| HVAC | HVAC+PAC | |
|---|---|---|
| Central forced air system operation | Intermittent | Intermittent |
| Efficiency of filter in central forced air system | Upgraded to High (MERV 13) | Upgraded to High (MERV 13) |
| Continuously operating portable air cleaner? | No | Yes |
| Experiment timeframe | 9/12–9/16 | 9/16–9/18 |
