Table 2.

Nomenclature terms of importance in this work for consideration of the risk due to toxicants in tobacco smoke

TermMeaningUnits
iA toxicant of interest (e.g., 1,3-butadiene, benzene, N-nitrosonornicotine, NNK, etc.)
AiPer cigarette smoke delivery (aka yield of toxicant i)μg/cigarette
zTotal smoking dose in pack-yearspack-years
Embedded ImageAverage (chronic) rate of daily intake of toxicant i by smoking when the total smoking dose is 1 pack-year and, in this work, when the dose is averaged over 70 ymg/kg d
Embedded ImageAverage (chronic) rate of daily intake of toxicant i by smoking when the total smoking dose is z pack-years and, in this work, when the dose is averaged over 70 ymg/kg-d
CSFiCancer slope factor for carcinogen i (also known as the cancer potency of i)(mg/kg-d)−1*
Embedded ImageIncremental calculated lifetime cancer risk for carcinogen i for a z = 1 pack-year smoking doserisk for 1 pack-year
Embedded ImageIncremental calculated lifetime cancer risk for carcinogen i for a smoking dose of z pack-yearsrisk for z pack-years
Embedded ImageAverage calculated value of the Embedded Image for a given group of cigarettes of a certain type (e.g., the average for all light cigarettes)risk for 1 pack-year
subΣA subtotal for a specific subset of carcinogens
subΣ-lungA subtotal for a specific subset of human lung carcinogens
Embedded ImageA subtotal of individual calculated Embedded Image for all carcinogens measured, with the smoking dose z = 1 pack-yearrisk for 1 pack-year
Embedded ImageAverage value of calculated Embedded Image for a given group of cigarette brands of a certain type (e.g., the average for light brands)risk for 1 pack-year
Embedded ImageSubΣ of individual calculated Embedded Image for all human lung carcinogens that have been measured (analytically), for a z = 1 pack-year smoking doserisk for 1 pack-year
Embedded ImageAverage value of calculated Embedded Image for a given group of cigarette brands of a certain type (e.g., the average for light brands)risk for 1 pack-year
Embedded ImageActual observed risk from smoking z pack-yearsrisk for z pack-years
MPercent match between Embedded Imagefor conventional cigarettes and Ω1lung%
RPREPAmount by which the calculatable per pack-year risk of lung cancer is reduced by switching from conventional cigarettes to a particular PREP%
Embedded ImageObserved total ILCRΣ−lung risk per pack-year for lung-cancer for z = 1 pack-year as averaged over all smokers and all smokers' doses in a particular real population (not a subΣ, but the full observed Σ)risk per pack-year
  • NOTE: For each ILCR value, a specific CDI is assumed. The units of each ILCR are “fractional risk.” For exposed individual, an ILCR = 0.001 indicates a 1 in 1,000 chance of cancer above the background risk.

  • * Because a CSF is a slope of cancer incidence versus CDI, a CSF may alternately be viewed as having units of risk/(mg/kg d).