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Effect of Filter Vent Blocking on Carbon Monoxide Exposure From Selected Lower Tar Cigarette Brands

https://doi.org/10.1016/S0091-3057(98)00250-0Get rights and content

Abstract

Two studies were conducted to determine the effect of blocking filter vents on carbon monoxide (CO) exposure under ad lib smoking conditions. In Study 1, 12 daily cigarette smokers smoked cigarettes from the brands Now® (1 mg tar by the FTC Method) and Marlboro Lights® (10 mg tar) under each of two vent-blocking conditions (unblocked and finger blocked). Blocking filter vents with fingers led to an 85% increase in CO for the brand Now, but had no added effect on CO exposure from the Marlboro Lights. In Study 2, another 12 daily cigarette smokers smoked cigarettes from each of four additional brands: Carlton® (1 mg tar), Now (2 mg tar), Virginia Slims Ultra-lights® (5 mg tar), and Virginia Slims Lights® (8 mg tar). Blocking filter vents with the lips caused all four brands to produce equal CO exposures. Blocking vents increased smokers’ exposure to CO by 239% when smoking Carltons and by 44% when smoking Nows. No significant increases in CO with blocking were found for either of the Virginia Slims brands. These results suggest that the degree to which a brand is ventilated determines whether that brand is susceptible to increased CO yields as a result of vent blocking.

Section snippets

Participants

Twelve cigarette smokers (six women and six men) were recruited through announcements posted on University bulletin boards and a television advertisement on a government education access channel. The average participant was 22 years old (range 19–33, SD = 4.0), smoked 22 cigarettes per day (range 15–30, SD = 5.3), and had been smoking regularly for 6.1 years (range 4–20, SD = 4.4). Two participants reported their usual brand as being Marlboro Full Flavor®, four Marlboro Lights, one Marlboro

Biological Exposure Measure

Baseline CO levels (i.e., expired-air CO scores at the start of each session, prior to smoking any cigarettes) ranged from 3.0 ppm to 49.0 ppm for the 12 participants (mean = 22.0; SD = 13.9).

Figure 1 shows the mean CO boosts with standard errors for both brands under both blocking conditions. Mean CO boosts were 2.0 ppm (SE = 0.57), 3.7 ppm (SE = 0.49), 6.1 ppm (SE = 0.84), and 5.9 ppm (SE = 0.79) for the unblocked Nows, blocked Nows, unblocked Marlboro Lights, and blocked Marlboro Lights,

Study 1: discussion

These results obtained under ad lib smoking conditions are very similar to those previously obtained under controlled smoking conditions. Blocking approximately half the filter vents with fingers on the Ultra-light cigarette brand Now led to almost a doubling (an 85% increase) of exposure to CO. In a previous study using the same vent blocking manipulation (i.e., finger blocking) a 93% increase in CO exposure due to vent blocking was observed for participants also smoking the brand Now (19).

Study 2

The purpose of Study 2 was to examine using additional cigarette brands the effects of vent blocking on smoke exposure, cigarette characteristics, and puff number under ad lib smoking conditions. Brands of varying ventilation levels and standard tar yields were used, allowing for a more specific examination of the influence of degree of filter ventilation on the effects of vent blocking. We wanted to examine whether brands within the Ultra-light tar yield category behave similarly with respect

Participants

Twelve female cigarette smokers were recruited through newspaper advertisements, fliers posted on University bulletin boards, and a television advertisement on a government education access channel. The average participant was 23 years old (range 18–50, SD = 9.0), smoked 20 cigarettes per day (range 15–35, SD = 6.0), and had been smoking regularly for 6.7 years (range 3–30, SD = 7.4). Seven participants reported their usual brand as being Marlboro Lights, two Camel Lights, two Parliament

Biological Exposure Measure

Average baseline CO levels (i.e., expired-air CO score at the start of each session, prior to smoking any cigarettes) were 7.7 ppm (SD = 3.9) for session 1 , 8.3 ppm (SD = 4.6) for session 2, 8.0 ppm (SD = 3.6) for session 3, and 7.0 ppm (SD = 3.6) for session 4.

Figure 2 shows the mean CO boosts with standard errors for all four brands of cigarettes under both blocking conditions.

Mean CO boosts were 1.8 ppm (SE = 0.41) and 6.1 ppm (SE = 0.86) for unblocked and blocked Carltons, respectively;

Study 2: discussion

When the filter vents on the 83% ventilated brand Carlton were not blocked, it was difficult for the smokers in this study to attain high CO yields, no matter how intensively they smoked these cigarettes. On average, CO exposure levels from this brand were 1.8 ppm when filter vents were not blocked. By covering the filter vents, however, this same brand produced CO levels of 6.1 ppm, more than tripling participants’ exposure to CO.

Somewhat smaller, though still statistically significant, was

General discussion

To date, six different brands of ventilated-filter cigarettes have been studied for the effects of behavioral vent blocking. Degree of filter ventilation, rather than its designation as “Ultra-light” or “Light,” appears to determine whether a brand is susceptible to increased CO yields as a result of vent blocking (although there is a high correlation between standard yields and percentage filter ventilation). Although blocking the filter vents of brands with ventilation levels of at least 66%

References (21)

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