Comparative HPHC Emission Profiles of Combustible and Alternative Nicotine Products in South Africa: Development of a Relative HPHC Emission Index

Abstract Alternative nicotine and tobacco products are increasingly available in South Africa, yet independent comparative data on their harmful and potentially harmful constituent (HPHC) emission profiles remain limited. The aim of this study was to compare mainstream emissions from an illicit combustible cigarette (Brand X), IQOS ILUMA heated tobacco products (TEREA Amber and TEREA Turquoise), a VEEV Now Ultra Mint disposable electronic nicotine delivery system, and ZYN modern oral nicotine pouches, with the 1R6F reference cigarette included as a combustible benchmark. Combustion-related markers CO, NO and NOx were evaluated in TEREA aerosols under synthetic-air and nitrogen atmospheres, while nine WHO-priority HPHCs were quantified using standardized analytical methods. Emissions were normalized to 100 cm3 of nominal puff volume where applicable. Brand X produced high emissions across the measured HPHC panel, including 4.91 ± 0.28 mg/100 cm3 CO, 248.67 ± 14.55 μg/100 cm3 acetaldehyde, 23.66 ± 2.27 μg/100 cm3 acrolein, 11.33 ± 1.43 μg/100 cm3 formaldehyde, 17.20 ± 0.75 μg/100 cm3 1,3-butadiene and 13.29 ± 1.01 μg/100 cm3 benzene. TEREA aerosols generated CO, NO and NOx concentrations below the BSI PAS 8850:2020 combustion-marker thresholds under both atmospheres, supporting the absence of combustion under the tested conditions. Across the WHO-9 panel, TEREA aerosols showed substantially lower emissions than combustible cigarette smoke, while VEEV showed quantifiable acetaldehyde and formaldehyde at low levels and most other target constituents below detection limits. Nicotine pouches showed a similarly restricted profile. Among TEREA variants, only NNN remained different after Holm adjustment. To integrate the multidimensional HPHC data, a Relative HPHC Emission Index (RHEI) was developed by normalizing each constituent to the highest emission among VEEV, TEREA Turquoise and Brand X and combining the nine constituent scores using equal weighting. The RHEI showed clear separation among the three products, with Brand X having the highest relative HPHC emission profile, TEREA Turquoise an intermediate profile, and VEEV the lowest. These findings provide an analytical basis for product-specific evaluation and surveillance of nicotine products in South Africa.