Is the 80th percentile the only breathing rate that should be included in a risk assessment?
No. The ARB, in consultation with OEHHA, is recommending the interim policy utilize the OEHHA HRA Guidance Manual’s range of exposure for determining potential cancer risk at the mean (65th percentile for the breathing pathway) and high-end (95th percentile) values. For the breathing pathway, this policy further recommends the use of the midpoint value of the percentile range (i.e., the 80th percentile) between the mean and high-end as the minimum exposure level for risk management decisions where a single cancer risk value must be used for a residential receptor.
