Philip Morris International is developing products with the potential to reduce the risk of smoking-related diseases by heating tobacco and avoiding combustion. The resulting aerosol has a less complex chemical composition and contains more water than conventional cigarette smoke.

It has been determined that the trapping and extraction procedure used for conventional cigarettes, defined in the International Standard ISO 4387, is not suitable for the high water content present in such heated tobacco aerosols. Errors occur because of water loss during the opening of the Cambridge filter pad holder to remove the filter as well as the manual handling of the filter, and because the plastic housing of the filter may absorb water. This results in inaccurate values for the water content, and erroneous and overestimated values for Nicotine Free Dry Particulate Matter (NFDPM).

A modified Cambridge filter holder and extraction equipment and methodology has been developed that involves the use of a metallic filter pad holder which supports in situ extraction from the Cambridge filter pad. Investigation has shown that this approach delivers more accurate water measurements for aerosols with high water content.

This equipment and methodology has also been used to collect the aerosol generated by conventional cigarettes and it was found that, for such aerosols, the water yield is larger than that generated by the ISO standard 4387, and that the difference in water yield between the two methods increases as the smoking regime intensity increases. However, for conventional cigarettes an impact on NFDPM values is only observed under intense smoking regimes.