| O'Halleran | Thomas | Air Quality Inspector II | Compliance and Enforcement | Compliance Assistance | 749-4979 | tohalleran |
| Okpalaugo | Mary Ann | Strategic Facilities Planning Manager | Administration | Strategic Facilities | 749-5127 | mokpalaugo |
| Orpia | Jocelyn | Radio/Telephone Operator | Compliance and Enforcement | Compliance Assistance | 749-4763 | jorpia |
| Ortellado | Juan | Air Quality Engineering Manager | Engineering | Permit Systems | 749-5183 | jortellado |
| Owen | Scott | Supervising Air Quality Engineer | Engineering | Toxic Evaluation | 749-4693 | sowen |