SummaryBackgroundCombustion as well as pyrolysis of tobacco greatly affect the type and levels of toxicants in cigarette smoke. We previously developed an approach to combine simultaneous temperature and pressure measurements with fast in-situ microprobe chemical sampling inside a burning cigarette, producing a series of temperature and gas-flow velocity maps that characterize this dynamic system in response to externally applied air flow.AimTwo cigarette types differing only in diameter were puffed under ISO 3308 and Health Canada Intense (HCI) regimes to further understand the dynamic interaction of air flow and cigarette design parameters on tobacco combustion and pyrolysis by applying the thermophysical and thermo-chemical mapping approach.MethodsThree types of sampling probes were inserted, which are thermocouple arrays for gas-phase temperature, quartz tubes for pressure measurement, and a heated sampling microprobe coupled to a single-photon soft ionisation mass spectrometer for chemical analysis. Two kinds of similarly constructed cigarettes with the same blend were analysed: superslim (17 mm circumference) and king-size (24 mm circumference).Synchronization among the sampled signals was achieved by mapping two probes (e.g., temperature/chemistry or temperature/pressure) at a time. The physical and chemical events were visualised and compared between the cigarettes and puffing regimes.ResultsA series of temperature, pressure, and chemical maps were obtained for the superslim and king-size cigarettes under ISO and HCI conditions. The pressure in the burning cigarette was higher in the superslim cigarette, and the temperature distribution differed between the two cigarette formats. As expected, temperatures and pressures were higher under HCI puffing than under ISO puffing for both cigarette formats. Thermochemical maps for e.g., benzene and nitric oxide formation were qualitatively similar between the superslim and king-size cigarettes. For other substances the distribution was markedly different.ConclusionThe application of multi-probe in-situ chemical sampling is suitable to analyse highly dynamic combustion and pyrolysis processes occurring inside the two types of cigarettes. Ultimately, a direct comparison of cigarette circumferences on the complex combustion processes and formation of smoke constituents was achieved. [Beitr. Tabakforsch. Int. 29 (2020) 44–54]
Methodical approach to temperature and pressure measurements for in situ energy-recovery processes