Contributing factors | Effective | Frequency % |
Hyper-air conditioning | 38 | 20.7% |
Overbreathing | 155 | 84.2% |
Insecticide | 67 | 36.4% |
Passive smoking | 50 | 27.6% |
Dust | 4 | 2.2% |
Incense | 122 | 66.3% |