| Envrionmental Factors | |||
| Normal |
Contaminated by Outside Dust |
Cold Weather | |
| Day Care | 2 weeks | 1 week | 2 weeks |
| Nursing Homes | 1 month | 1 month | 1 month |
| Residence | |||
| 2 person, nonsmoking | 6-12 months | 2 months | 4-6 months |
| 2 persons, smoking | 4 months | 2 months | 3 months |
| Young Children | 6 months | 1 month | 2 months |
| Office Building | |||
| Ground Floor | 3-6 months | 1-4 months | 2-6 months |
| Higher Floors | 6-12 months | 2-6 months | 3-9 months |
| Food Service Establishments | 1 month | 1 week | 2-6 months |
| Commericial | 3-6 months | 1 months | 2 months |