Table 4 Summary of available uncertainties in various risk factors.

Air pollution:

10 μg m^-3 increase in PM_2.5

RR of mortality is 1.04 with 95% CI: 1.01–1.08 [3] but note unexamined confounding factors could increase uncertainty.

Passive smoking:

Long-term exposure compared to little or no exposure.

RR of lung cancer [32] is 1.24 with 95% CI: 1.13–1.36

RR of heart disease [33] is 1.23 with 95% CI: 1.14–1.33

Excess mortality risk [36] was based only on heart disease RR of 1.31 and 1.24 for males and females respectively, at the higher end of the range given by [33].

Obesity:

High BMI compared to "normal" BMI = 24

Uncertainty in YOLL not presently available. Ref. [26] states that "we were unable to provide confidence intervals for our YLL estimates. We are unaware of any developed analytic formula that would allow easy calculation of SEs and confidence intervals". Uncertainties in relative risks are illustrated in Figure 2.

Radiation:

Risk per unit dose equivalent.

Subjective 95% CI was given for NAS risk analysis [14] where it was stated that "estimates that are a factor of two or three larger or smaller cannot be excluded" (see also [54]). This uncertainty is expected to also apply to the ICRP [15] risk estimates presented here. In particular, it is uncertain whether a DDREF should be applied: if a DDREF was not applied, this would increase the ICRP risk estimates by a factor of 2.