Methodology of evaluating the toxic risks from chemical contamination of air on piloted orbital stations.
- Paper number
IAC-08.A1.5.6
- Author
Dr. Lana Moukhamedieva, Institute for Biomedical Problems, Russia
- Coauthor
Ms. Anna Pakhomova, Institute for Biomedical Problems, Russia
- Year
2008
- Abstract
Improvement and application of the methodology and criteria of evaluating the risks to human health constitute the outstanding area of research aimed at substantiation of approaches to providing crew toxicological and hygienic protection in the event of chemical pollution of atmosphere of orbital stations {OS}. The scientific substantiation of the toxic risks evaluation methodology is based on understanding of the process of building-up of the multicomponent contamination, and the hazard to human organism from simultaneous exposure to chemicals varying in character and intensity of toxic effect. It was shown that the permanent and main sources of many trace contaminants found in the OS atmosphere are man-caused; the main contributors to the overall air contamination, they are responsible for quantitative and qualitative variations in airborne chemicals, and episodic outbursts in concentrations of chemicals-markers. A particular role in rising the level of contamination and appearance of new pollutants is played by chemical transformations producing secondary, more toxic compounds. In the context of the above, during the development of risks evaluation methodology much attention was given to the assessment of toxic risks of:
- brief exposure to contaminated environment such as during the first ingress into modules of the station on the phase of construction, as well as arrival of cargo and transport vehicles;
- growing air contamination due to implementation of long-duration missions and acute exposure in the event of contingency and emergency conditions.
Methodology of toxic risk evaluation in the event of brief exposure {(first ingress into a module}) is defined by efficiency of actions towards reduction of the level of air modules contamination including:
- Sanitary-hygienic procedures in conjunction with the ground-based preparation of new modules, cargo and transport vehicles;
- Prediction of the level of air contamination after a period of autonomous flight and development of hygienic procedures to ensure safe first ingress in new module;
- Toxicological evaluation and choice of effective personal protection means.
Methodology of toxic risk evaluation in the event of long exposure in OS atmosphere containing a variety of contaminants {(long-duration missions}) is defined by calculating the contributions from:
- Internal and external sources of contaminants;
- Aging and biodestruction of nonmetal and metal materials used in the ISS systems and equipment, and payloads;
- Chemical reagents and biological materials delivered with payloads;
- Growing number of crew members;
- Chemical transformation producing secondary, more toxic compounds within the air purification and regeneration systems, and also under the influence of such microfactors of the space environment as ionization of atmosphere, ionizing and solar radiation, oxidants.
Methodology of toxic risk evaluation and crew protection in the event of acute exposure due to contingency consists of the next stages:
- Toxicological classification of situation;
- Gathering data about the level, character and nature {(volley or prolonged}) of contamination;
- Calculation of time for contamination equalization within the module where contingency has occurred;
- Calculation of probable concentrations of contaminants in each OS module;
- Control actions including the choice of personal protection means and calculation of crew reserve time.
- Abstract document
- Manuscript document
IAC-08.A1.5.6.pdf (🔒 authorized access only).
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