Table 3

Mean (SD) of physical characteristics of cigarettes from different studies

		China (current study)		O'Connor et al (2008)18		Counts et al (2005)22
Parameter		Mean	SD	Mean	SD	Mean	SD
No tested		78		172		48
Pressure drop		109.6^*	11.4	98.6	15.3	NR
Ventilation		6.4^* ^†	10.7	37.8	21.6	37.3	22.1
Tobacco rod length		61.7^*	2.6	59.9	3.3	NR
Tipping paper length		28.9	2.6	28.2	3.1	NR
Tobacco weight		683.3^*	36.9	640.0	79.1	679.0	86.8
Rod density		243.2^*	11.7	229.1	23.7	NR
Filter density		114.2^*	5.3	122.2	10.9	NR
Paper permeability		53.3^†	9.6	NR		45.0	16.5

↵* significantly different from O'Connor et al18 at p<0.0001 by t test.
↵† significantly different from Counts et al22 at p<0.001 by t test.
NR, not reported.