# Table 2 Smoke exposure measures and CO boost, by type of cigarette smoked; 2nd, 3rd, 4th cigarettes averaged

Averages, per cigarette (standard deviations)

Smokers of Roll-your-own (RYO) cigarettes

n = 26

Smokers of Factory-made (FM) cigarettes

n = 22

p value for the RYO â€“ FM difference of means

Weight of tobacco mg per cigarette

496.5 (7.47)

695.3 (15.0)

<0.001*

Net weight of tobacco burnt, own cigarette brand, mg

400.3 (48.4)

552.4 (87.8)

<0.001*

CO increase per cigarette, ppm

4.37 (2.06)

4.24 (2.52)

0.846

CO ppm increase per g of tobacco burnt;

10.82 (4.98)

7.60 (4.26)

0.021*

Total smoke inhaled per cigarette (total puff volume) mL

952.1 (387.7)

742.6 (188.8)

0.025*

Smoke inhaled in mL, per g of tobacco burnt

2392.6 (1013.0)

1356.0 (321.4)

<0.001*

Smoke inhaled per day mL #

18803 (13030)

13242 (6738)

0.077

Puffs per cigarette, count

16.9 (5.2)

13.6 (5.4)

0.035*

Smoke volume per puff, mL

57.3 (17.1)

58.9 (16.8)

0.744

Smoke flow mL/second

33.9 (10.4)

35.2 (9.3)

0.663

Smoke peak flow ml/second

51.0 (18.2)

51.4 (14.0)

0.928

Duration per puff seconds

1.72 (0.40)

1.77 (0.45)

0.664

Average inter-puff interval, seconds

16.67 (9.44)

18.67 (7.11)

0.419

Time puffing per cigarette, seconds

28.4 (9.1)

22.4 (5.9)

0.012*

Puffing as % of time smoking

11.67 (4.51)

10.24 (3.58)

0.235

Minutes smoking, per cigarette

4.29 (0.99)

3.86 (0.96)

0.139

Cravings from after 1st to after 4th cigarette

24.2 (28.2) to 10.1 (21.6)

19.8 (25.2) to 6.1 (9.1)

0.332

1. *p values (statistically significant at p =< 0.05) are based on Chi-squared tests for categorical measures and independent t-tests for continuous measures.
2. # Product of smoke volume per cigarette and number of cigarettes per day (from Table 1).