Spills of liquid oxygen could also create significant local impacts, primarily on ecosystems. The extreme cold is the principal cause of damage. Although data are available on the results of transportation accidents, these have not been translated into actual health and safety effects, i.e., injury rates. To do so would require an analysis of accident probability and an evaluation of probable transport corridors to determine public exposure to these hazards. This analysis is planned as part of the research program on safety hazard. Launch and Recovery Air Quality. The launch activity results in air quality impacts from the exhaust products of the launch vehicle and from the formation and dispersion of a "ground cloud" at the launch platform made up of exhaust gases, cooling water, and some sand and dust. Because of launch trajectory and vehicle speed, the majority of the exhaust products are emitted in the troposphere (0—11 km) although a sizable quantity is also emitted in the stratosphere (11-50 km) (Ref. 2.8.3). The ground cloud, on the other hand, is developed at the launch pad and will rise to between 0. 7 and 3 km where its bouyancy is neutralized by a cooling of the gases. The ground cloud has been the subject of extensive research, particularly with regard to its generation by the space shuttle program (Ref. 2.8.9). The ground cloud has the potential for creating direct public exposure to air pollutants because of its low altitude. A mathematical model has been developed to estimate the maximum concentrations of various pollutants in the ground cloud as a result of space shuttle operations. These results are not directly applicable to SPS operations because of the probable use of liquid-fueled rockets (vs solid-fueled for the shuttle) and the significantly larger launch vehicle size. The model has not yet been exercised for the SPS launch vehicle configuration of Ref. 2.8.1. As a result of previous work, it is possible to identify ambient concentration limits for various launch-related air pollutants. Table 2.4 gives the standards used for the space shuttle program based on the National Ambient Air Quality Standards promulgated by the U.S. EPA and on exposure limits recommended by the Committee on Toxicology of the National Academy of Sciences (NAS)/National Research Council (NRC). The NAS/NRC recommendations include a short-term public limit (STPL) designed to avoid an irritation of
RkJQdWJsaXNoZXIy MTU5NjU0Mg==