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Space-faring crews must have safe breathing air throughout their missions to ensure adequate performance and good health. Toxicological assessment of air quality depends on the standards that define acceptable air quality, measurements of pollutant levels during the flight, and reports from the crew on their in-flight perceptions of air quality. Air samples returned from ISS on flights 8A, UF2, 9A, and 11A were analyzed for trace pollutants. On average, the air during this period of operations was safe for human respiration. However, about 3 hours into the regeneration of 2 Metox canisters in the U.S. airlock on 20 February 2002 the crew reported an intolerable odor that caused them to stop the regeneration, take refuge in the Russian segment, and scrub air in the U.S. segment for 30 hours. Analytical data from grab samples taken during the incident showed that the pollutants released were characteristic of nominal air pollutants, but were present in much higher concentrations.

Space-faring crews must have safe breathing air throughout their missions to ensure adequate performance and good health. Toxicological assessment of air quality depends on the standards that define acceptable air quality, measurements of pollutant levels during the flight, and reports from the crew on their in-flight perceptions of air quality. Air samples from ISS flights 2A.2a, 2A.2b, 3A, and 4A were analyzed for trace pollutants. On average the air during each flight was safe for human respiration. However, there were reports from the crew that they experienced a headache when in certain areas, and strong odors were reported from specific locations of the ISS complex. Inspection of air samples in these locations suggested that several of the solvent-type pollutants (e.g. ethyl acetate, xylenes, and n-butanol) were present in concentrations that would cause a strong odor to be perceived by some individuals.

There are many sources of air pollution that can threaten air quality during space missions. The International Space Station (ISS) is an extremely complex platform that depends on a multi-tiered strategy to control the risk of excessive air pollution. During the seven missions surveyed by this report, the ISS atmosphere was in a safe, steady-state condition; however, there were minor loads added as new modules were attached. There was a series of leaks of octafluoropropane, which is not directly toxic to humans, but did cause changes in air purification operations that disrupted the steady state condition. In addition, off-nominal regeneration of metal oxide canisters used during extravehicular activity caused a serious pollution incident.

At last year’s International Conference on Environmental Systems, a technical paper was presented showing the loss of several compounds stored in dual sorbent tubes (DSTs) for long periods (>60 days). At the time, DSTs were virtually the only source available to the U.S. to assess trace contaminant concentrations in spacecraft air; therefore the compound losses were an important problem that needed to be addressed. This paper will update results from the DSTs returned on 9S and 10S Soyuz missions during the latter part of 2005. The data acquired from these DSTs will be compared to the 7S and 8S data presented last year. Discussion will focus on the reliability of correction factors and identification of any trends in the data. Additionally, test plans to investigate the cause of the problem and improve the DSTs will be detailed.

The primary means to assess spacecraft air quality during a mission, for crew health purposes, has been archival air samplers that are returned to the ground for analysis. One such sampler is the Dual Sorbent Tube (DST) developed in late 2003 by the Toxicology group at the Johnson Space Center. The DSTs provided a low mass, low-volume sampler that was compatible with the constraints of the Soyuz return vehicle. The first set of DSTs, including positive control tubes, flew to the International Space Station (ISS) aboard Soyuz in January 2004 and they were returned in May 2004. The analytical recovery of compounds from the positive controls provides an indication of the stability of contaminants in the sampler. Analysis of the first returned set of positive controls revealed poor recoveries for several of the compounds. The low recoveries from the positive controls led to a study of compound stability on DSTs for long storage periods.

The crew of flight 2A.1 that manned the International Space Station (ISS) assembly mission (STS-96) in May 1999 experienced symptoms that they attributed to poor air quality while working in the ISS modules. Some of these symptoms suggested that an accumulation of carbon dioxide (CO2) in the work area could have contributed to temporary health impacts on the crew. Currently, a fixed-position CO2 monitor in the FGB is the only means of measuring this air contaminant aboard ISS. As a result of this incident, NASA directed the Toxicology Laboratory at Johnson Space Center (JSC) to deliver a portable CO2 monitor for the next ISS assembly mission (STS-101). The Toxicology Laboratory developed performance requirements for a CO2 monitor and surveyed available CO2 monitoring technologies. The selected portable CO2 monitor uses nondispersive infrared spectroscopy for detection. This paper describes this instrument, its operation, and presents the results from ground-based performance testing.