The Effect of Some Nitrogenous Blend Components on NO/NOx and HCN Levels in Mainstream and Sidestream Smoke

Vapour phase NO concentrations in mainstream and sidestream smoke correlated well with blend nitrate levels over the range from 0.07 to 3.70 %. Native and added nitrate fit the same correlation. No measurable amounts of NO₂ were detected in the vapour phase. When the mainstream and sidestream data were extrapolated to zero nitrate level, there remained a large residual amount of NO (approximately 100 µg /cig.) which could be attributed neither to nitrate nor to other nitrogenous blend components of the total volatile base type. Nitrogen-free cellulose cigarettes yielded of the order of 50 µg of NO per cigarette indicating that part of the residual NO probably arises from the oxidation of atmospheric nitrogen. The particulate phase contained small but measurable levels of nitrate which, with the exception of Mg(NO₃) × 6 H₂O added cigarettes, did not relate to blend nitrate levels. Mainstream vapour phase HCN level correlated weakly with blend nitrate levels but other nitrogenous materials whether native or added showed no clearly defined precursor-product relationship with smoke HCN yield. The partitioning of HCN between the vapour and particulate phases was not affected by any of the test variables.