Skip to main content

Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants Volume 5 (2008) / Chapter Skim
Currently Skimming:

Introduction
Pages 1-10

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 1...
... Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants Volume 5
Read the entire page →
From page 3...
... To protect space crews from air contaminants, NASA requested that the National Research Council (NRC) provide guidance for developing spacecraft maximum allowable concentrations (SMACs)
Read the entire page →
From page 4...
... SMACs are defined as the maximum concentrations of airborne substances that will not produce adverse health effects, cause significant discomfort, or degrade crew performance. SMACs are classified into 1- and 24-hour (h)
Read the entire page →
From page 5...
... Risk assessments for exposure to noncarcinogenic substances traditionally have been based on the premise that an adverse health effect will not occur below a specific threshold exposure. Given this assumption, an exposure guidance level can be established by dividing the no-observed-adverse-effect level (NOAEL)
Read the entire page →
From page 6...
... Special Considerations for NASA When deriving SMACs, by either the NOAEL/LOAEL or the BMD approach, it is necessary to use exposure conversions and uncertainty factors to adjust for weaknesses or uncertainties about the data. When adequate data are available, exposure conversions that NASA should use include those to adjust for target tissue dose, differences in exposure duration, species differences, and differences in routes of exposure.
Read the entire page →
From page 7...
... Some of the ways astronauts can be physically, physiologically, and psychologically compromised include decreased muscle mass, decreased bone mass, decreased red blood cell mass, depressed immune systems, altered nutritional requirements, behavioral changes, shift of body fluids, altered blood flow, altered hormonal status, altered enzyme concentrations, increased sensitization to cardiac arrhythmias, and altered drug metabolism. There is generally little information to permit a quantitative conversion that would reflect altered toxicity resulting from spaceflight environmental factors.
Read the entire page →
From page 8...
... Washington, D.C.: National Academy Press. NRC (National Research Council)
Read the entire page →
From page 9...
... Washington, DC: National Academy Press. NRC (National Research Council)
Read the entire page →

Key Terms

  • airborne contaminants
  • exposure guidelines
  • spacecraft maximum
  • selected airborne
  • maximum allowable

  • uncertainty factors
  • allowable concentrations
  • developing smacs
  • aliphatic saturated
  • carbon monoxide

  • target tissue
  • methylene chloride
  • saturated aldehydes
  • exposure duration
  • exposure conversions

  • exposure data
  • developing spacecraft
  • cancer risk
  • toxicity studies
  • toxicity data

  • guidelines set
  • assessment methods
  • smac reports
  • crew performance
  • propylene glycol

  • exposure durations
  • animal exposure
  • exposure guidance
  • chronic exposure
  • threshold exposure


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
    More information on Chapter Skim is available.