Total number of ultrafine particles (0.02 to 1 μm) | Carbon monoxide (mg) | |||
Waterpipe | 74.4 (16.3)×109 | 1.79 (0.61) | ||
Cigarette | 9.24 (−1.2)×109 | 1.06 (0.50) |
Mean values (SD). Differences between waterpipes and cigarettes were significant for particles (t test, p<0.001) and CO (t test, p<0.01).