| Category | Examples |
| Respiratory tract infections | Influenza Pneumococcal disease Pertussis Rhinovirus RSV |
| Allergens | Animals Cockroaches House dust mite Moulds Pollens Occupational allergens |
| Airborne irritants | Cigarette smoke Smoke (including bushfires, vegetation reduction fires, indoor wood fires) Cold/dry air Fuel stoves Gas heaters Home renovation materials Household aerosols Moulds (airborne endotoxins) Occupational irritants Outdoor industrial and traffic pollution Perfumes/scents/incense |
| Medicines | Aspirin and NSAIDs (in patients with aspirin-exacerbated respiratory disease) Beta-blockers Echinacea |
| Dietary | Food chemicals/additives (if person is intolerant) Thermal effects (e.g. cold drinks) |
| Physiological and psychological states | Exercise Laughter Extreme emotions Pregnancy |