Fibre and Particle Release from Cigarette Filters

Particulates, especially those in the respirable fraction, are generally suspected of being responsible for a host of respiratory and cardiovascular health problems that may include an increase in morbidity and mortality. These effects have been related not only to the carbonaceous particulates, such as diesel soot, but also to more inert dust particles without any specific intrinsic hazard.

Therefore, any exposure to respirable dust from consumer products, and especially from tobacco products, is of considerable concern. In this context, a report of particular interest to the general public purported to show that cellulose acetate fibres released from cigarette filters could represent an additional burden and risk to the smoker. The underlying presumption was that these fibres could be respired and retained in portions of the respiratory tract, in particular in the lung.

In response to these assertions, studies were performed by and on behalf of the affected industry and the results showed that these fibres did not pose a health risk. The findings revealed that some acetate fibres were generated during the processing of the cigarettes, but they were captured on the cross-section of the cigarette filter and remained on the filter during smoking. Those fibres potentially released during smoking would be deposited inside the mouth area because they were too large to pass the larynx and could not physically enter the bronchial or pulmonary sections of the respiratory tract.

A working group from the German StandardisationOrganisation (DIN) recently discussed the experimental findings regarding the fibres generated during the processing of the acetate cigarette filter. Additional examinations on the release of respirable particles were initiated using Scanning Electron Microscope (SEM) to focus special attention on fibre-shaped particulates. The results of these recent analyses and the former findings led the group to the conclusion that ‘from the toxicological perspective, compared to the health risks otherwise associated with cigarette smoking, the release of particles from acetate filters does not constitute a particular health risk’.

Subsequent to this review and evaluation of the results some additional examinations were performed to examine further aspects of particle release. Using an improved analytical technique with real-time detection, the particle number and sizes were determined for the release of respirable particles from cigarettes and cigarette filters. The studies were performed by drawing air through filters and filter cigarettes in a clean room under intense smoking conditions, and the particles were analysed in real time with a Laser Aerosol Spectrometer. Using this technique, approximately 10 particles with a size greater than 0.3 ìm were counted per cigarette. This is comparable to a particle load in a clean room environment and representing approx. 0.05% of the particle load in ambient air.