Air exposures calculation details
Long-term (chronic) inhalation or dermal exposure can be estimated using a single value derived from single-value inputs. MCRA implements the same calculation method as the RSExpo tool for inhalation and dermal contact.
Air exposures are generated using properties age and sex of a simulated set of individuals or, as an alternative, an existing set of individuals (currently, the dietary individual population, see module dietary exposures). Specify the reference population with option Specify individuals for generating air exposures with settings Simulate individuals or Use dietary individuals.
Inhalation exposure
The calculation for inhalation exposure is:
Parameters used in the equation
\(\mathtt{E_{air-inhal}}\): average daily external exposure of an individual to substances by air inhalation (default in \(\mu g/kg \, bw /day\))
\(\mathtt{BW}\): body weight of the individual (default in \(kg\))
\(\mathtt{F_a}\): daily ventilatory flow (\(m^3/day\))
\(\mathtt{t_{in}}\): fraction of daily time spend indoors (\(/1\))
\(\mathtt{c_{in,a}}\): substance concentration in indoor air (default in \(\mu g/m^3\))
\(\mathtt{c_{out,a}}\): substance concentration in outdoor air (default in \(\mu g/m^3\))
Dermal exposure
The calculation for dermal exposure is:
Parameters used in the equation
\(\mathtt{E_{air-derm}}\): average daily external exposure of an individual to substances by air dermal contact (default in \(\mu g/kg \, bw /day\))
\(\mathtt{BW}\): body weight of the individual (default in \(kg\))
\(\mathtt{S}\): body surface (\(m^2\))
\(\mathtt{F_{s,a}}\): fraction of the body surface exposed to air (\(/1\)), default = 0.15
\(\mathtt{v_p}\): deposition velocity of airborne particles onto the skin’s surface (\(m/day\)), default = 2.15
\(\mathtt{t_{in}}\): fraction of daily time spend indoors (\(/1\))
\(\mathtt{c_{in,a}}\): substance concentration in indoor air (default in \(\mu g/m^3\))
\(\mathtt{c_{out,a}}\): substance concentration in outdoor air (default in \(\mu g/m^3\))