get.fug.concs: get.fug.concs

In HumanExposure/SHEDSDevel: The SHEDS-HT model for estimating human exposure to chemicals.

Description

Performs fugacity calculations to evaluate time-dependent chemical flows.

Usage

get.fug.concs(sdata, chem.data, x, cfug)

Arguments

sdata	The chemical-scenario data specific to relevant combinations of chemical and scenario. Generated internally.
chem.data	The list of scenario-specific information for the chemicals being evaluated. Generated internally.
x	The output of the add.fugs function.
cfug	The output of the chem_fug function, a data set with the chemical specific parameters for each combination of chemical and simulated person. For each chemical, the chemical specific parameters assigned to a given person are randomly sampled from distributions on those parameters. These distributions are created from point estimates to reflect real-world uncertainty and variability.

Details

This is one of two functions that perform fugacity calculations. This one evaluates dynamic or time-dependent chemical First, a set of local variables are determined for use in later calculations. These are a mix of fixed and chemical-dependent variables (evaluated separately for each person). Some variables, like chemical mass and app.rates, vary with each source, so these calculations are repeated for each source-scenario. Second, the eigenvalues and eigenvectors of the jacobian matrix are calculated. Since the fugacity model has been reduced to just two compartments (air and surface), the solutions can be expressed analytically, and there is no explicit invocation of any linear algebra routines that would normally be required. Third, the variables composing the concs output are evaluated. The variables m.c.air and m.c.sur are the time-constant masses, while m.t0.air and m.t0.sur are the time-dependent masses at t=0. The time-constant parts are zero here because the permanent sources (i.e. c.src.air and c.src.sur) are assumed to be zero in these calculations. The time-dependent masses are multiplied exponentially as a function of time, and thus approach zero when enough time has passed.

Value

concs A data set containing calculated dynamic chemical flows for each unique combination of simulated person and chemical.

Author(s)

Kristin Isaacs, Graham Glen

See Also

chem_fugs, Fugacity, Run, run, get.y0.concs

HumanExposure/SHEDSDevel documentation built on Oct. 30, 2019, 6:49 p.m.