Description
Divide integratedConcentrationTime by occupiedTime when useOccupied is true, otherwise by totalTime, and return occupancyFraction = occupiedTime/totalTime.
Exposure arithmetic combines a concentration with time, intake or body mass on an explicit averaging basis. Integrated contact, average concentration, ingested mass and absorbed dose are different quantities and should not be substituted for each other.
Divide integratedConcentrationTime by occupiedTime when useOccupied is true, otherwise by totalTime, and return occupancyFraction = occupiedTime/totalTime.
When to use this tool
Use Indoor Exposure Occupied Time Base when checking a supplied exposure integration or averaging denominator.
How to use the tool and how it works
- Enter integratedConcentrationTime, occupiedTime, totalTime, useOccupied. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read timeAverage, occupancyFraction. Use the output convention below.
Require positive occupiedTime and totalTime with occupiedTime <= totalTime. Divide integratedConcentrationTime by occupiedTime when useOccupied is true, otherwise by totalTime, and return occupancyFraction = occupiedTime/totalTime. The integrated input must be concentration multiplied by time in the same time unit as both denominators.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| integratedConcentrationTime | Supplied concentration-time integral, using the same time unit as both averaging denominators. | Required. Finite number. |
| occupiedTime | Occupied Time | Required. Finite number; strictly above 0. |
| totalTime | Total Time | Required. Finite number; strictly above 0. |
| useOccupied | Use Occupied | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| timeAverage | Time Average | Required. Finite number. |
| occupancyFraction | Occupancy Fraction | Required. Finite number. |
{
"input": {
"integratedConcentrationTime": 100,
"occupiedTime": 5,
"totalTime": 10,
"useOccupied": true
},
"output": {
"timeAverage": 20,
"occupancyFraction": 0.5
}
}Limitations and assumptions
- The integral is supplied, not derived from measurements. Changing the denominator changes the averaging basis, not the recorded integral; signed integral inputs are accepted and no individual dose or health conclusion is inferred.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use a suitable exposure assessment with frequency, routes, variability and toxicological context when the question concerns health consequences.
References
Similar or alternative tools
- Radon Exposure Time Weighted One Room Term
Return integratedExposure = roomConcentration*roomHours*occupancyWeight+otherConcentration*otherHours and meanConcentration = integratedExposure/weightedHours.
- Household Exposure Unit Factor Tool
Apply an explicit compatible exposure-measurement unit factor without risk assessment.