Documentation for ICRP Publication 66 Lung Deposition Model

ICRP Pub 66 Lung Deposition Model

Calculates the percentage deposition of aerosols to specific regions of the lungs:

Extrathoracic Region I (ET1)

Extrathoracic Region II (ET2)

Bronchial Region (BB)

Bronchiolar Region (bb)

Alveolar-Interstitial Region (AI)

The Lung Deposition Model was developed (in C++) by Stefanie Holmes as part of her ERULF project in the summer of 1999. This web implementation was developed by Lin Ahmad as part of her ORNL/NSF research project in the summer of 2002. This code is an implementation of the ICRP Human Respiratory Tract Model for Deposition in the Lung (ICRP Publication 66). This implementation has been validated against a previous FORTRAN version. The web CGI scripts are written in perl and the documentation uses Extensible Markup Language including structured vector graphics (SVG) and MATHML.

As input the Model uses 1) a file containing physiological parameters (such as tidal volume, breathing rates, etc.) and 2) a file containing environmental factors (aerosol size and shape) along with characteristics of the test subject (gender, height, etc.). To run the Model, the user enters the information in this second file. At the present time the user cannot change the information in the file containing physiological parameters. A perl script captures and validates the user's input. User's input is written to a file. This file together with physiological data (in a file) are used as inputs to the C++ Object Oriented implementation of the Lung Deposition Model. The results of the computation are displayed to the user's web browser.

The following tables explain the input parameters to the model, the physiological data, and the the C++ methods in the application (depmono2) developed by Stefanie Holmes.

Model Parameters

Description of Parameter	Units	Example of Input
Subject's gender	m or f	f
Subject's height	cm	176
Subject's breathing habit	n=nasal m=mouth	n
Wind speed	m/s	0
Mono or Poly disperse	m=mono p=poly	m
Particle shape factor	Unitless	1.5
Particle density	micron	3.5109
Standard deviation (if known) for polydisperse	Unitless	0
Sleep	Hours	8
Sitting	Hours	8
Light exercise	Hours	8
Heavy exercise	Hours	0

Documentation of C++ Object Oriented Code:

Class: Person

Variables associated with the class Units Comments Variables associated with the class Units Comments

double height cm Subject's height double SFt Unitless BB scale factor

double Vt mL Volume of tidal airflow double SFb Unitless bb scale factor

double Vdot mL/s Ventilatory airflow double SFa Unitless AI scale factor

double VdET mL Anatomical dead space double tB Transit Time

double VdBB mL Anatomical dead space - Bronchial double tb Transit Time

double Vdbb mL Anatomical dead space - bronchiolar double ta Units Transit Time

double Fn Units Fraction of total ventilatory airflow passing through nose char gender m=male f=female Subject's gender (m or f)

double FRC mL Functional residual capacity char breathe n=nasal m=mouth Nose or mouth breather

double B m^3/h Ventilation rate

Methods associated with the class Units Comments Methods associated with the class Units Comments

void calcTB(); Calculate transit time in the BB region void calcTb(); Calculate transit time in the bb region

void calcTa(); Calculate transit time in the AI region

Class: Environment

Variables associated with the class	Units	Comments	Variables associated with the class	Units	Comments
double U	m/s	environmental wind speed	Person *body		A reference to the class Person
Methods associated with the class	Units	Comments	Methods associated with the class	Units	Comments
double getU()		Get the wind speed

Class: Particle

Variables associated with the class	Units	Comments	Variables associated with the class	Units	Comments
char disp	m or p	Mono or poly disperse	double dae	micron	Aerodynamic diameter (mono) or AMTD (poly)
double dth	micron	Thermodynamic diameter (mono) or AMTD (poly)	double psith		Correction coefficient for thermodynamic deposition caused by nonlaimnar flow
double D		Diffusion coefficient	double rho	g cm^-3	Particle density
double chi		Particle shape factor	double fs		Slow-cleared fraction
Methods associated with the class	Units	Comments	Methods associated with the class	Units	Comments
double calcCd();			void calcD();		Calculate diffusion coefficient
void calcPsith();		Calculate correction coefficient for thermodynamic deposition caused by nonlaminar flow	double correctDth();		Calculate thermodynamic diameter
void calcDae();		Calculate aerodynamic diameter	void calcFs();

Class: Region

Variables associated with the class	Units	Comments	Variables associated with the class	Units	Comments
double eta	Unitless	Total filtration efficiency	double phi	Unitless	Fraction of tidal airflow volume
double xi	Unitless	Ratio of this region's phi to the previous region's phi	double DE	Unitless	Deposition fraction
double aeroA	Unitless	Parameter for calculating aerodynamic efficiency	double aeroR	Unitless	Parameter for calculating aerodynamic efficiency
double aeroP	Unitless	Parameter for calculating aerodynamic efficiency	double thermA	Unitless	Parameter for calculating aerodynamic efficiency
double thermR	Unitless	Parameter for calculating aerodynamic efficiency	double thermP	Unitless	Parameter for calculating aerodynamic efficiency
static char exertType[4][MAX_NAME]		Type of physical activity	static double exertTime[4]	Hours	Length of time spent doing each activity
Methods associated with the class	Units	Comments	Methods associated with the class	Units	Comments
calc_aRp(double _a, double _r, double _p)		Calculates a*(R^p)	calcEta()		Calculates filtration efficiency
calcXi(double prevPhi)		Ratio of this region's phi to the previous region's phi	calcDE(double prevDE, double prevEta)		Calculates deposition fraction

Class: FilterX

Variables associated with the class	Units	Comments	Variables associated with the class	Units	Comments
double aeroEta		Aerodynamic deposition efficiency	double thermaEta		Thermodynamic deposition efficiency
Methods associated with the class	Units	Comments	Methods associated with the class	Units	Comments
void FilterX::calcA()			void FilterX::calcR()
void FilterX::calcP()			double FilterX::calcEta()
double FilterX::calcPhi(double prevPhi)			double FilterX::calcDE(double prevEta)
doulbe FilterX::calcDE(double prevDE, double prevEta)

Main Function

Variables associated with the class	Units	Comments	Variables associated with the class	Units	Comments
double totalDE[h]	Unitless	Accumulated deposition in each of the compartments (ET1, ET2, BB, bb, and AI)	bxt	m^3	Breathing rate for the particular activity * duration
_prevEtaNO	Unitless		_prevEtaMO	Unitless
_prevPhiNO	Unitless		_prevPhiMO	Unitless
_prevEtaN	Unitless	At each filter stage, the previous value of eta	_currEtaN	Unitless	At each filter stage, the current value of eta
_prevPhiN	Unitless	At each filter stage, the previous value of phi	_currPhiN	Unitless	At each filter stage, the current value of phi
_prevDeN	Unitless	At each filter stage, the previous value of DE	_currDeN	Unitless	At each filter stage, the current value of DE
Methods associated with the class	Units	Comments	Methods associated with the class	Units	Comments
void calcFn(Person *person, int num)	unitless	Gives fraction of breathe going thourgh nasal passage	double combineN(double de, Person *person, int n)
double combineM(double de, Person *person, int n)			void compDep(Particle *dust, double dep[])
getData1(_body, fio, x)		_body is a pointer to the object, body, of the class Person. fio is the stream open for reading. double x[NUM_DATA}	getData2(_body, fio, x)